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As the field of cell and gene therapy (CGT) continues to grow, so too must the infrastructure and regulatory guidance supporting the manufacture of these potentially life-saving products-especially early-phase products manufactured at an increasing number of academic or hospital-based facilities providing decentralized (or point of care) manufacturing. An important component of current good manufacturing practices, including those regulating cell and gene therapies, is the establishment of an effective environmental monitoring (EM) program. While several guidelines for establishing an EM program are available, these guidelines do not specifically address the unique aspects of manufacturing CGT products and they do not provide real-world evidence demonstrating the effectiveness of the program. Here, we describe the establishment and evolution of an EM program in a cell therapy manufacturing facility at an academic hospital. With 10 years of EM data, we analyze the effectiveness for identifying trends in environmental conditions and highlight important findings, with the aim of providing practical evidence and guidance for the development of future early-phase EM programs., Competing Interests: Declaration of Competing Interest PJH is an advisor or on the advisory board of Cellevolve, Cellenkos, March Biosciences, Autolomous and Microfluidx., (Copyright © 2024 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Reactivation or primary infection with double-stranded DNA viruses is common in recipients of solid organ transplants (SOTs) and is associated with significant morbidity and mortality. Treatment with conventional antiviral medications is limited by toxicities, resistance, and a lack of effective options for adenovirus (ADV) and BK polyomavirus (BKPyV). Virus-specific T cells (VSTs) have been shown to be an effective treatment for infections with ADV, BKPyV, cytomegalovirus (CMV), and Epstein-Barr virus (EBV). Most of these studies have been conducted in stem cell recipients, and no large studies have been published in the SOT population to date. In this study, we report on the outcome of quadrivalent third-party VST infusions in 98 recipients of SOTs in the context of an open-label phase 2 trial. The 98 patients received a total of 181 infusions, with a median of 2 infusions per patient. The overall response rate was 45% for BKPyV, 65% for cytomegalovirus, 68% for ADV, and 61% for Epstein-Barr virus. Twenty percent of patients with posttransplant lymphoproliferative disorder had a complete response and 40% of patients had a partial response. All the VST infusions were well tolerated. We conclude that VSTs are safe and effective in the treatment of viral infections in SOT recipients., (Copyright © 2024. Published by Elsevier Inc.)

Background: Significant advancements have been made in the field of cellular therapy as anti-cancer treatments, with the approval of chimeric antigen receptor (CAR)-T cell therapies and the development of other genetically engineered cellular therapies. CAR-T cell therapies have demonstrated remarkable clinical outcomes in various hematological malignancies, establishing their potential to change the current cancer treatment paradigm. Due to the increasing importance of genetically engineered cellular therapies in the oncology treatment landscape, implementing strategies to expedite development and evidence generation for the next generation of cellular therapy products can have a positive impact on patients., Methods: We outline a risk-based methodology and assessment aid for the data extrapolation approach across related genetically engineered cellular therapy products. This systematic data extrapolation approach has applicability beyond CAR-T cells and can influence clinical development strategies for a variety of immune therapies such as T cell receptor (TCR) or genetically engineered and other cell-based therapies (e.g., tumor infiltrating lymphocytes, natural killer cells and macrophages)., Results: By analyzing commonalities in manufacturing processes, clinical trial designs, and regulatory considerations, key learnings were identified. These insights support optimization of the development and regulatory approval of novel cellular therapies., Conclusions: The field of cellular therapy holds immense promise in safely and effectively treating cancer. The ability to extrapolate data across related products presents opportunities to streamline the development process and accelerate the delivery of novel therapies to patients., Competing Interests: Declaration of competing interest M.K. holds IP related to cell therapy, assigned to the University of Pennsylvania and licensed to Novartis, board memberships with IMVinc, Nanocell therapeutics, and is on scientific advisory boards for AdicetBio, Annoca AG, cTRL-therapeutics, Cue Biopharma, Lykan Bioscience, Senti Biosciences, Vittoria Therapeutics. J.J is an employee of Kite, A Gilead Company. J.Y. is an employee of Janssen R&D, LLC. M.F is an employee of Novartis. S.G. is an employee of Allogene Therapeutics. C.G. is an employee of GSK. P.J.H. is a Scientific Advisor or Advisory Board for Cellenkos, Cellevolve, Discovery Life Sciences, Microfluidx, Autolomous, Capsida and is co-founder, board of directors of Mana Therapeutics. J.H. is an employee of Merck & Co. Inc. W. L. is an employee of Lyell Immunopharma. L.P. is an employee of the Canadian Cancer Trials Group and past employee of GSK, and holds shares in GSK. S.P.T reports that Moffitt Cancer Center has licensed Intellectual Property (IP) related to the proliferation and expansion of tumor infiltrating lymphocytes (TILs) to Iovance Biotherapeutics. Moffitt has also licensed IP to Tuhura Biopharma. S.P.T. is an inventor on such Intellectual Property. SPT has received consulting fees from Seagen Inc., Morphogenesis Inc., and KSQ Therapeutics. M.V. is an employee of Genentech, Inc. J.V. is an employee of A2 Biotherapeutics, Inc. S.W. is an employee of Bristol Myers Squibb. All other authors report no potential conflicts., (Copyright © 2024 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Initially, the two members of class 18 myosins, Myo18A and Myo18B, appeared to exhibit highly divergent functions, complicating the assignment of class-specific functions. However, the identification of a striated muscle-specific isoform of Myo18A, Myo18Aγ, suggests that class 18 myosins may have evolved to complement the functions of conventional class 2 myosins in sarcomeres. Indeed, both genes, Myo18a and Myo18b , are predominantly expressed in the heart and somites, precursors of skeletal muscle, of developing mouse embryos. Genetic deletion of either gene in mice is embryonic lethal and is associated with the disorganization of cardiac sarcomeres. Moreover, Myo18Aγ and Myo18B localize to sarcomeric A-bands, albeit the motor (head) domains of these unconventional myosins have been both deduced and biochemically demonstrated to exhibit negligible ATPase activity, a hallmark of motor proteins. Instead, Myo18Aγ and Myo18B presumably coassemble with thick filaments and provide structural integrity and/or internal resistance through interactions with F-actin and/or other proteins. In addition, Myo18Aγ and Myo18B may play distinct roles in the assembly of myofibrils, which may arise from actin stress fibers containing the α-isoform of Myo18A, Myo18Aα. The β-isoform of Myo18A, Myo18Aβ, is similar to Myo18Aα, except that it lacks the N-terminal extension, and may serve as a negative regulator through heterodimerization with either Myo18Aα or Myo18Aγ. In this review, we contend that Myo18Aγ and Myo18B are essential for myofibril structure and function in striated muscle cells, while α- and β-isoforms of Myo18A play diverse roles in nonmuscle cells., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Horsthemke, Arnaud and Hanley.)

Viral infections remain a major risk in immunocompromised pediatric patients, and virus-specific T cell (VST) therapy has been successful for treatment of refractory viral infections in prior studies. We performed a phase II multicenter study (NCT03475212) for the treatment of pediatric patients with inborn errors of immunity and/or post allogeneic hematopoietic stem cell transplant with refractory viral infections using partially-HLA matched VSTs targeting cytomegalovirus, Epstein-Barr virus, or adenovirus. Primary endpoints were feasibility, safety, and clinical responses (>1 log reduction in viremia at 28 days). Secondary endpoints were reconstitution of antiviral immunity and persistence of the infused VSTs. Suitable VST products were identified for 75 of 77 clinical queries. Clinical responses were achieved in 29 of 47 (62%) of patients post-HSCT including 73% of patients evaluable at 1-month post-infusion, meeting the primary efficacy endpoint (>52%). Secondary graft rejection occurred in one child following VST infusion as described in a companion article. Corticosteroids, graft-versus-host disease, transplant-associated thrombotic microangiopathy, and eculizumab treatment correlated with poor response, while uptrending absolute lymphocyte and CD8 T cell counts correlated with good response. This study highlights key clinical factors that impact response to VSTs and demonstrates the feasibility and efficacy of this therapy in pediatric HSCT., (© 2024. The Author(s).)

Virus-specific T cells (VST) from partially-HLA matched donors have been effective for treatment of refractory viral infections in immunocompromised patients in prior studies with a good safety profile, but rare adverse events have been described. Here we describe a unique and severe adverse event of VST therapy in an infant with severe combined immunodeficiency, who receives, as part of a clinical trial (NCT03475212), third party VSTs for treating cytomegalovirus viremia following bone marrow transplantation. At one-month post-VST infusion, rejection of graft and reversal of chimerism is observed, as is an expansion of T cells exclusively from the VST donor. Single-cell gene expression and T cell receptor profiling demonstrate a narrow repertoire of predominantly activated CD4 + T cells in the recipient at the time of rejection, with the repertoire overlapping more with that of peripheral blood from VST donor than the infused VST product. This case thus demonstrates a rare but serious side effect of VST therapy., (© 2024. The Author(s).)

Background: The histone deacetylase inhibitor vorinostat (VOR) can reverse human immunodeficiency virus type 1 (HIV-1) latency in vivo and allow T cells to clear infected cells in vitro. HIV-specific T cells (HXTCs) can be expanded ex vivo and have been safely administered to people with HIV (PWH) on antiretroviral therapy., Methods: Six PWH received infusions of 2 × 107 HXTCs/m² with VOR 400 mg, and 3 PWH received infusions of 10 × 107 HXTCs/m² with VOR. The frequency of persistent HIV by multiple assays including quantitative viral outgrowth assay (QVOA) of resting CD4+ T cells was measured before and after study therapy., Results: VOR and HXTCs were safe, and biomarkers of serial VOR effect were detected, but enhanced antiviral activity in circulating cells was not evident. After 2 × 107 HXTCs/m² with VOR, 1 of 6 PWH exhibited a decrease in QVOA, and all 3 PWH exhibited such declines after 10 × 107 HXTCs/m² and VOR. However, most declines did not exceed the 6-fold threshold needed to definitively attribute decline to the study intervention., Conclusions: These modest effects provide support for the strategy of HIV latency reversal and reservoir clearance, but more effective interventions are needed to yield the profound depletion of persistent HIV likely to yield clinical benefit. Clinical Trials Registration. NCT03212989., Competing Interests: Potential conflicts of interest. C. M. B. is a scientific co-founder and scientific advisory board member for Catamaran Bio and Mana Therapeutics; serves on the board of directors of Cabaletta Bio; has stock in Neximmune and Repertoire Immune Medicine; serves on the data and safety monitoring board for SOBI; and has served on advisory boards for BMS, Roche, and Pfizer. D. M. M. has provided consultancy to ViiV Healthcare outside of this work and owns common stock in Gilead Sciences. P. J. H. is a co-founder and serves on the board of directors of Mana Therapeutics and is an advisor to Cellenkos, Cellevolve, Discovery Life Sciences, Capsida, and MicroFluidX. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Quality control testing and analytics are critical for the development and manufacture of cell and gene therapies, and flow cytometry is a key quality control and analytical assay that is used extensively. However, the technical scope of characterization assays and safety assays must keep apace as the breadth of cell therapy products continues to expand beyond hematopoietic stem cell products into producing novel adoptive immune therapies and gene therapy products.  Flow cytometry services are uniquely positioned to support the evolving needs of cell therapy facilities, as access to flow cytometers, new antibody clones and improved fluorochrome reagents becomes more egalitarian. This report will outline the features, logistics, limitations and the current state of flow cytometry within the context of cellular therapy., Competing Interests: Declaration of Competing Interest PJH is a co-founder and on the board of directors of Mana Therapeutics. He is or was an advisor or on the scientific advisory board of: Cellenkos, Cellevolve, Discovery Life Sciences, Capsida, Autolomous, MicrofluidX and March Biosciences. CAL has no disclosures., (Copyright © 2023 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Prostatic acid phosphatase (PAP) exists as two splice variants, secreted PAP and transmembrane PAP, the latter of which is implicated in antinociceptive signaling in dorsal root ganglia. However, PAP is predominantly expressed in the prostate gland and the physiological role of seminal PAP, first identified in 1938, is largely unknown. Here, the author proposes that PAP, following ejaculation, functions to hydrolyze phosphocholine (PC) in seminal fluid and generate choline, which is imported by sperm via a choline transporter and converted to acetylcholine (ACh) by choline acetyltransferase. Auto- and paracrine cholinergic signaling, or choline directly, may subsequently stimulate sperm motility via α7 nicotinic ACh receptors (nAChRs) and contractility of the female reproductive tract through muscarinic ACh receptors (mAChRs). Consistent with a role of PAP in cholinergic signaling, 1) seminal vesicles secrete PC, 2) the prostate gland secretes PAP, 3) PAP specifically catalyzes the hydrolysis of PC into inorganic phosphate and choline, 4) seminal choline levels increase post-ejaculation, 5) pharmacological inhibition of choline acetyltransferase inhibits sperm motility, 6) inhibition or genetic deletion of α7 nAChRs impairs sperm motility, and 7) mAChRs are expressed in the uterus and oviduct (fallopian tube). Notably, PAP does not degrade glycerophosphocholine (GPC), the predominant choline source in the semen of rats and other mammals. Instead, uterine GPC phosphodiesterases may liberate choline from seminal GPC. In summary, the author deduces that PAP in humans, and uterine GPC phosphodiesterases in other mammals, function to generate choline for sperm cholinergic signaling, which promotes sperm motility and possibly contractility of the female reproductive tract., Competing Interests: The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Hanley.)

Background: Neurologic impairments are a significant concern for survivors after pediatric cardiac surgery with cardiopulmonary bypass (CPB). We have previously shown that mesenchymal stromal cell (MSC) delivery through CPB has the potential to mitigate the effects of CPB on neural stem/progenitor cells. This study assessed the dose effects of MSCs., Methods: Piglets (n = 20) were randomly assigned to 1 of 4 groups: control, CPB, or CPB followed by MSC administration with low and high doses (10 × 10 6 and 100 × 10 6 cells per kilogram). We assessed acute dose effect on cell distribution, multiorgan functions, systemic inflammation, microglia activation, and neural stem/progenitor cell activities., Results: By magnetic resonance imaging, approximately 10 times more MSCs were detected within the entire brain after high-dose delivery than after low-dose delivery. No adverse events affecting hemodynamics, various biomarkers, and neuroimaging were detected after high-dose MSC delivery. High-dose MSCs significantly increased circulating levels of interleukin 4 after CPB. Both MSC groups normalized microglia activation after CPB, demonstrating MSC-induced reduction in cerebral inflammation. There was a significant increase in neuroblasts in the subventricular zone in both treatment groups. The thickness of the most active neurogenic area within the subventricular zone was significantly increased after high-dose treatment compared with CPB and low-dose MSCs, suggesting dose-dependent effects on the neurogenic niche., Conclusions: MSC delivery through CPB is feasible up to 100 × 10 6 cells per kilogram. MSC treatment during cardiac surgery has the potential to reduce systemic and cerebral inflammation and to modulate responses of an active neurogenic niche to CPB. Further investigation is necessary to assess the long-term effects and to develop a more complete dose-response curve., (Copyright © 2023 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Oxidative/inflammatory stresses due to cardiopulmonary bypass (CPB) cause prolonged microglia activation and cortical dysmaturation, thereby contributing to neurodevelopmental impairments in children with congenital heart disease (CHD). This study found that delivery of mesenchymal stromal cells (MSCs) via CPB minimizes microglial activation and neuronal apoptosis, with subsequent improvement of cortical dysmaturation and behavioral alteration after neonatal cardiac surgery. Furthermore, transcriptomic analyses suggest that exosome-derived miRNAs may be the key drivers of suppressed apoptosis and STAT3-mediated microglial activation. Our findings demonstrate that MSC treatment during cardiac surgery has significant translational potential for improving cortical dysmaturation and neurological impairment in children with CHD., Competing Interests: This work was supported by National Institutes of Health (NIH) grants R01HL139712 (Dr Ishibashi), R01HL146670 (Dr Ishibashi), R21NS127051 (Dr Ishibashi) and NIMHHD U54MD007597 (Dr Wang) and by the Office of the Assistant Secretary of Defense for Health Affairs through the Peer Reviewed Medical Research Program under award no. W81XWH2010199 (Dr Ishibashi). The Clinical and Translational Science Institute was supported through NIH UL1TR001876 and KL2TR001877. District of Columbia Intellectual and Developmental Disabilities Research Center (DC-IDDRC) cores were supported by NIH U54HD090257. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH, U.S. Department of Defense, or DC-IDDRC. Dr Hanley is a cofounder and on the Board of Directors of Mana Therapeutics, is on the Scientific Advisory Board of Cellevolve, and is an advisor to Maxcyte. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Hematopoietic stem cell transplantation (HSCT) is being increasingly used as a curative approach for sickle cell disease (SCD). With the risk of graft-versus-host disease (GVHD), especially in the human leukocyte antigen-mismatched donors, intense immunosuppression is required leading to an increased risk of viral infection. Post-HSCT, adoptive transfer of virus-specific T-cell (VST) therapies have not been well-studied in patients with SCD. Here, we report the outcomes of patients with SCD at a single-center who received VSTs after transplant to prevent or treat viral infections. Thirteen patients who received HSCT from human leukocyte antigen-matched (n = 9) or -mismatched (n = 4) donors for SCD were treated with a total of 15 VST products for the treatment or prophylaxis of multiple viruses (cytomegalovirus, Epstein-Barr virus, adenovirus, BK virus, human herpes virus 6 +/- human parainfluenza virus 3). Of the patients evaluated, 46.2% (n = 6)) received VSTs as treatment for viral infection. Eighty percent of patients with active viremia (n = 4/5) achieved remission of at least 1 target virus. Seven additional patients (53.8%) received VSTs prophylactically and 6 of 7 (85.7%) remained virus-free after infusion. No immediate infusion-related toxicities occurred, and severe de novo acute GVHD occurred in only 2 (15.4%) patients. Given the good safety profile, high-rate of clinical responses and sustained remissions when administered with standard antiviral treatments, the routine use of VSTs after HSCT as prophylaxis or treatment may improve the overall safety of transplant for patients with SCD., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Infections with double-stranded DNA viruses are a common complication after hematopoietic stem cell transplantation (HSCT) and cause significant morbidity and mortality in the post-transplantation period. Both donor-derived (DD) and third-party (TP) virus-specific T cells (VSTs) have shown efficacy and safety in viral management following HSCT in children and young adults. Owing to a greater degree of HLA matching between the recipient and stem cell donor, DD VSTs potentially persist longer in circulation compared to TP VSTs, because they are collected from a well-matched donor. However, TP VSTs are more easily accessible, particularly for smaller transplantation centers that do not have VST manufacturing capabilities, and more economical than creating a customized product for each transplant recipient. We conducted the present study to compare clinical efficacy and safety outcomes for DD VSTs and TP VSTs in a large cohort of pediatric and young adult HSCT recipients and to determine whether DD VSTs are associated with improved outcomes owing to potentially longer persistence in the recipient's circulation. This retrospective cohort study included 145 patients who received VSTs at Cincinnati Children's Hospital Medical Center (CCHMC) between 2017 and 2021 for the treatment of adenovirus, BK virus, cytomegalovirus, and/or Epstein-Barr virus. Viruses were detected using quantitative polymerase chain reaction. Patients received VSTs on a DD (NCT02048332) or TP (NCT02532452) protocol, and VST products for both protocols were manufactured in an identical fashion. The primary study outcome was clinical response to VSTs, evaluated 4 weeks after VST administration, defined as decrease in viral load to under the inclusion thresholds, or resolution of symptoms of invasive viral infection, without the need for additional conventional antiviral medication following VST administration. Secondary outcomes included graft-versus-host-disease, transplant-associated thrombotic microangiopathy, renal function, hospital length of stay, and overall survival at 30 days and 100 days after VST administration and 1 year after HSCT. Statistical analysis was performed using the Fisher exact test or chi-square test. An unpaired t test was used to compare continuous variables. The study group comprised 77 patients in the DD cohort and 68 patients in the TP cohort. Eighteen patients in the TP cohort underwent HSCT at CCHMC, and the other 50 underwent HSCT at other institutions and presented to CCHMC solely for VST administration. There was no statistically significant difference in clinical response rates between DD and TP cohorts (65.6% versus 62.7%; odds ratio [OR], 1.162; 95% confidence interval [CI], .619 to 2.164; P = .747). There were no significant differences in secondary outcomes between the 2 cohorts. The percentage of patients requiring multiple infusions for a clinical response did not differ significantly between the DD and TP cohorts (38.2% versus 32.5%; OR, .780; 95% CI, .345 to 1.805; P = .666). We found no significant difference in clinical response rate between DD VSTs and TP VSTs and a similar safety profile. Our data suggest that TP VSTs may be sufficient to control viral infection until immune reconstitution occurs despite the potential for more rapid VST clearance compared to DD VSTs. The lack of significant differences between DD VSTs and TP VSTs is an important finding, indicating that it is not necessary for every transplant center to manufacture customized DD VSTs, and that TP VSTs are a satisfactory substitute., (Copyright © 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Background Aims: The field of cell and gene therapy in oncology has moved rapidly since 2017 when the first cell and gene therapies, Kymriah followed by Yescarta, were approved by the Food and Drug Administration in the United States, followed by multiple other countries. Since those approvals, several new products have gone on to receive approval for additional indications. Meanwhile, efforts have been made to target different cancers, improve the logistics of delivery and reduce the cost associated with novel cell and gene therapies. Here, we highlight various cell and gene therapy-related technologies and advances that provide insight into how these new technologies will speed the translation of these therapies into the clinic., Conclusions: In this review, we provide a broad overview of the current state of cell and gene therapy-based approaches for cancer treatment - discussing various effector cell types and their sources, recent advances in both CAR and non-CAR genetic modifications, and highlighting a few promising approaches for increasing in vivo efficacy and persistence of therapeutic drug products., Competing Interests: Declaration of Competing Interest P.J.H. is a co-founder, consultant and serves on the board of directors of Mana Therapeutics. He is on the scientific advisory boards of Cellevolve, Cellenkos, Discovery Life Sciences and MicroFluidx and has consulted for Maxcyte., (Copyright © 2022 International Society for Cell & Gene Therapy. All rights reserved.)

Mechanisms keeping leukocytes distant of local inflammatory processes in a resting state despite systemic release of inflammatory triggers are a pivotal requirement for avoidance of overwhelming inflammation but are ill defined. Dimers of the alarmin S100A8/S100A9 activate Toll-like receptor-4 (TLR4) but extracellular calcium concentrations induce S100A8/S100A9-tetramers preventing TLR4-binding and limiting their inflammatory activity. So far, only antimicrobial functions of released S100A8/S100A9-tetramers (calprotectin) are described. It is demonstrated that extracellular S100A8/S100A9 tetramers significantly dampen monocyte dynamics as adhesion, migration, and traction force generation in vitro and immigration of monocytes in a cutaneous granuloma model and inflammatory activity in a model of irritant contact dermatitis in vivo. Interestingly, these effects are not mediated by the well-known binding of S100A8/S100A9-dimers to TLR-4 but specifically mediated by S100A8/S100A9-tetramer interaction with CD69. Thus, the quaternary structure of these S100-proteins determines distinct and even antagonistic effects mediated by different receptors. As S100A8/S100A9 are released primarily as dimers and subsequently associate to tetramers in the high extracellular calcium milieu, the same molecules promote inflammation locally (S100-dimer/TLR4) but simultaneously protect the wider environment from overwhelming inflammation (S100-tetramer/CD69)., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Adoptive T cell immunotherapy has been used to restore immunity against multiple viral targets in immunocompromised patients after bone-marrow transplantation and has been proposed as a strategy for preventing coronavirus 2019 (COVID-19) in this population. Ideally, expanded severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-virus-specific T cells (CSTs) should demonstrate marked cell expansion, T cell specificity, and CD8+ T cell skewing prior to adoptive transfer. However, current methodologies using IL-4 + IL-7 result in suboptimal specificity, especially in CD8 + cells. Using a microexpansion platform, we screened various cytokine cocktails (IL-4 + IL-7, IL-15, IL-15 + IL-4, IL-15 + IL-6, and IL-15 + IL-7) for the most favorable culture conditions. IL-15 + IL-7 optimally balanced T cell expansion, polyfunctionality, and CD8+ T cell skewing of a final therapeutic T cell product. Additionally, the transcriptomes of CD4 + and CD8 + T cells cultured with IL-15 + IL-7 displayed the strongest induction of antiviral type I interferon (IFN) response genes. Subsequently, microexpansion results were successfully translated to a Good Manufacturing Practice (GMP)-applicable format where IL-15 + IL-7 outperformed IL-4 + IL-7 in specificity and expansion, especially in the desirable CD8 + T cell compartment. These results demonstrate the functional implications of IL-15-, IL-4-, and IL-7-containing cocktails for therapeutic T cell expansion, which could have broad implication for cellular therapy, and pioneer the use of RNA sequencing (RNA-seq) to guide viral-specific T cell (VST) product manufacturing., Competing Interests: P.J.H. is a cofounder and is on the board of directors of Mana Therapeutics. P.J.H. is on a scientific advisory board for Cellevolve. M.D.K. is on a scientific advisory panel for Gilead Sciences. The remaining authors declare no competing financial interests., (© 2022 The Authors.)

Infections with double-stranded DNA viruses are a significant cause of morbidity and mortality in pediatric patients following allogeneic hematopoietic stem cell transplantation (HSCT). Virus-specific T-cell therapies (VSTs) have been shown to be an effective treatment for infections with adenovirus, BK virus, cytomegalovirus (CMV), and Epstein-Barr virus (EBV). To date, prophylactic regimens to prevent or mitigate these infections using conventional antiviral medications provide suboptimal response rates. Here we report on a clinical trial (NCT03883906) performed to assess the feasibility of rapid manufacturing and early infusion of quadrivalent VSTs generated from stem cell donors ("donor-derived VSTs") into allogeneic HSCT recipients with minimal or absent viremia. Patients were eligible to receive scheduled VSTs as early as 21 days after stem cell infusion. Twenty-three patients received scheduled VSTs. Twenty of 23 patients had no viremia at the time of infusion, while 3 patients had very low-level BK viremia. Two developed clinically significant graft-versus-host disease (GVHD), although this incidence was not outside of expected incidence early after HSCT, and both were successfully treated with systemic corticosteroids (n = 2). Five patients were deemed treatment failures. Three developed subsequent significant viremia/viral disease (n = 3). Eighteen patients did not fail treatment, 7 of whom did not develop any viremia, while 11 developed low-level, self-limited viremia that resolved without further intervention. No infusion reactions occurred. In conclusion, scheduled VSTs appear to be safe and potentially effective at limiting serious complications from viral infections after allogeneic transplantation. A randomized study comparing this scheduled approach to the use of VSTs to treat active viremia is ongoing., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Patients with hematologic malignancies relapsing after allogeneic blood or marrow transplantation (BMT) have limited response to conventional salvage therapies, with an expected 1-year overall survival (OS) of <20%. We evaluated the safety and clinical outcomes following administration of a novel T-cell therapeutic targeting 3 tumor-associated antigens (TAA-T) in patients with acute leukemia who relapsed or were at high risk of relapse after allogeneic BMT. Lymphocytes obtained from the BMT donor were manufactured to target TAAs WT1, PRAME, and survivin, which are over-expressed and immunogenic in most hematologic malignancies. Patients received TAA-T infusions at doses of 0.5 to 4 × 107/m2. Twenty-three BMT recipients with relapsed/refractory (n = 11) and/or high-risk (n = 12) acute myeloid leukemia (n = 20) and acute lymphoblastic leukemia (n = 3) were infused posttransplant. No patient developed cytokine-release syndrome or neurotoxicity, and only 1 patient developed grade 3 graft-versus-host disease. Of the patients who relapsed post-BMT and received bridging therapy, the majority (n = 9/11) achieved complete hematologic remission before receiving TAA-T. Relapsed patients exhibited a 1-year OS of 36% and 1-year leukemia-free survival of 27.3% post-TAA-T. The poorest prognosis patients (relapsed <6 months after transplant) exhibited a 1-year OS of 42.8% postrelapse (n = 7). Median survival was not reached for high-risk patients who received preemptive TAA-T posttransplant (n = 12). Although as a phase 1 study, concomitant antileukemic therapy was allowed, TAA-T were safe and well tolerated, and sustained remissions in high-risk and relapsed patients were observed. Moreover, adoptively transferred TAA-T detected by T-cell receptor V-β sequencing persisted up to at least 1 year postinfusion. This trial was registered at clinicaltrials.gov as #NCT02203903., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Progressive multifocal leukoencephalopathy (PML) is a progressive and generally fatal demyelinating neurologic disease that occurs in profoundly immunocompromised patients due to infection with the human polyomavirus JC virus (JCPyV). Treatment options are limited and are largely focused on restoring T cell immunity, and outcomes are historically poor. Control of JCPyV in the setting of an immunocompromised patient by adoptive transfer of third-party virus specific T cells (VSTs) has been described in a small number of cases. To investigate treatment response and outcomes in recipients of hematopoietic stem cell transplantation (HSCT) with PML treated with third-party VSTs directed against the BK virus, a highly homologous polyoma virus that shares immunogenic epitopes with JCPyV. A retrospective chart review was performed on 4 patients who received VSTs for the treatment of PML at Cincinnati Children's Hospital Medical Center since 2019. VSTs were administered safely, with no cases of graft-versus-host disease and no infusion reactions. One patient who was treated almost immediately after diagnosis was able to clear JCPyV from blood and cerebrospinal fluid, with resultant stabilization of neurologic decline. IFN-γ enzyme-linked immunospot (ELISpot) analysis demonstrated VSTs in the peripheral blood following infusion. Response was maintained through repeat infusions. Three other patients, all of whom had a longer delay between diagnosis and infusion, exhibited progressive neurologic decline despite varying degrees of improvement in viral load. PML is a rare but often fatal complication following HSCT for which few treatment options are available. BK-directed, JCPyV cross-reactive VSTs are a safe and viable therapeutic option, and prompt administration should be considered once PML is diagnosed. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc., (Copyright © 2021 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Hodgkin lymphoma (HL) Reed Sternberg cells express tumor-associated antigens (TAA) that are potential targets for cellular therapies. We recently demonstrated that TAA-specific T cells (TAA-Ts) targeting WT1, PRAME, and Survivin were safe and associated with prolonged time to progression in solid tumors. Hence, we evaluated whether TAA-Ts when given alone or with nivolumab were safe and could elicit antitumor effects in vivo in patients with relapsed/refractory (r/r) HL. Ten patients were infused with TAA-Ts (8 autologous and 2 allogeneic) for active HL (n = 8) or as adjuvant therapy after hematopoietic stem cell transplant (n = 2). Six patients received nivolumab priming before TAA-Ts and continued until disease progression or unacceptable toxicity. All 10 products recognized 1 or more TAAs and were polyfunctional. Patients were monitored for safety for 6 weeks after the TAA-Ts and for response until disease progression. The infusions were safe with no clear dose-limiting toxicities. Patients receiving TAA-Ts as adjuvant therapy remain in continued remission at 3+ years. Of the 8 patients with active disease, 1 patient had a complete response and 7 had stable disease at 3 months, 3 of whom remain with stable disease at 1 year. Antigen spreading and long-term persistence of TAA-Ts in vivo were observed in responding patients. Nivolumab priming impacted TAA-T recognition and persistence. In conclusion, treatment of patients with r/r HL with TAA-Ts alone or in combination with nivolumab was safe and produced promising results. This trial was registered at www.clinicaltrials.gov as #NCT022039303 and #NCT03843294., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

There is considerable interest in the next generation of personalized medicine, especially cell and gene therapy products such as chimeric antigen receptor T cells (CAR-Ts). Unlike other small molecules or pharmacologic drugs, most existing cell or cell-based gene therapy products (CGTs) require apheresis collection of the patient or donor, subsequent manufacture of the product, and final shipment of the product to the clinical site for infusion. Whereas traditional pharmaceutical drugs have involved the drug sponsor and the clinical site and clinical pharmacy, this new manufacturing paradigm has evolved, in many cases, to include an apheresis center, a cell processing lab, the sponsor's manufacturing facility, and a clinical site with or without a pharmacy. Here we report the results of a survey of current practices handling investigational CGTs conducted by the Immuno-Gene Therapy committee of the International Society of Cell and Gene Therapy., Competing Interests: Conflict of Interest P.J. Hanley is a co-founder and on the board of directors of Mana Therapeutics and serves as an advisor to Cellevolve and Maxcyte. A. Bersenev is a co-founder of Cell Trials Data and co-founder and Managing Director of CellBioEngines., (Copyright © 2021 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Background: Leukoreduction to eliminate mononuclear cells within blood products is necessary to prevent graft-versus-host disease after transfusion. Published reports document low concentrations of mononuclear cells leftover in fresh-frozen plasma products, however the phenotype and the proliferative potential of these cells has not been tested., Materials and Methods: We investigated residual cellular components contained within fresh and fresh-frozen plasma products and characterised their proliferative potential in co-cultures with unrelated allogeneic cells. We designed a flow-based assay to phenotype cells and quantify cell division by measuring the dilution of fluorescently labeled protein as cells divide. Leukocytes from consenting donors were purified from fresh liquid or fresh-frozen plasma units and cultured for three to seven days with unrelated irradiated allogeneic targets., Results: We discovered a median of 1.6×10 7 viable lymphocytes were detectable in fresh plasma units after collection (n=8), comprised of a mixture of CD3+ CD8+ and CD3+ CD4+ cells. Furthermore, we identified a median of 8.4% of live CD3+ plasma lymphocytes divided as early as Day 4 when co-cultured with unrelated allogeneic cells, expanding to a median 88.8% by Day 7 (n=3). Although freezing the plasma product reduced the total number of viable leukocyte cells down to 2.3×10 5 (n=10), residual naive CD3+ cells were viable and demonstrated division through Day 7 of co-culture., Discussion: The evidence of viable proliferative lymphocytes in fresh and fresh-frozen plasma products derived from centrifugation suggests that additional leukoreduction measures should be investigated to fully eradicate reactive lymphocytes from centrifuged plasma products.

Infection with adenoviruses is a common and significant complication in pediatric patients after allogeneic hematopoietic stem cell transplantation. Treatment options with traditional antivirals are limited by poor efficacy and significant toxicities. T-cell reconstitution is critical for the management of adenoviral infections, but it generally takes place months after transplantation. Ex vivo-generated virus-specific T cells (VSTs) are an alternative approach for viral control and can be rapidly generated from either a stem cell donor or a healthy third-party donor. In the context of a single-center phase 1/2 clinical trial, we treated 30 patients with a total of 43 infusions of VSTs for adenoviremia and/or adenoviral disease. Seven patients received donor-derived VSTs, 21 patients received third-party VSTs, and 2 received VSTs from both donor sources. Clinical responses were observed in 81% of patients, with a complete response in 58%. Epitope prediction and potential epitope identification for common HLA molecules helped elucidate HLA restriction in a subset of patients receiving third-party products. Intracellular interferon-γ expression in T cells in response to single peptides and response to cell lines stably transfected with a single HLA molecule demonstrated HLA-restricted CD4+ T-cell response, and these results correlated with clinical outcomes. Taken together, these data suggest that VSTs are a highly safe and effective therapy for the management of adenoviral infection in immunocompromised hosts. The trials were registered at www.clinicaltrials.gov as #NCT02048332 and #NCT02532452., (© 2021 by The American Society of Hematology.)

Background Aims: Preferentially expressed antigen in melanoma (PRAME) is a cancer/testis antigen that is overexpressed in many human malignancies and poorly expressed or absent in healthy tissues, making it a good target for anti-cancer immunotherapy. Development of an effective off-the-shelf adoptive T-cell therapy for patients with relapsed or refractory solid tumors and hematological malignancies expressing PRAME antigen requires the identification of major histocompatibility complex (MHC) class I and II PRAME antigens recognized by the tumor-associated antigen (TAA) T-cell product. The authors therefore set out to extend the repertoire of HLA-restricted PRAME peptide epitopes beyond the few already characterized., Methods: Peptide libraries of 125 overlapping 15-mer peptides spanning the entire PRAME protein sequence were used to identify HLA class I- and II-restricted epitopes. The authors also determined the HLA restriction of the identified epitopes., Results: PRAME-specific T-cell products were successfully generated from peripheral blood mononuclear cells of 12 healthy donors. Ex vivo-expanded T cells were polyclonal, consisting of both CD4+ and CD8+ T cells, which elicited anti-tumor activity in vitro. Nine MHC class I-restricted PRAME epitopes were identified (seven novel and two previously described). The authors also characterized 16 individual 15-mer peptide sequences confirmed as CD4-restricted epitopes., Conclusions: TAA T cells derived from healthy donors recognize a broad range of CD4+ and CD8+ HLA-restricted PRAME epitopes, which could be used to select suitable donors for generating off-the-shelf TAA-specific T cells., Competing Interests: Declaration of Competing Interest CMB is on the advisory board of Cellectis and the scientific advisory boards of Catamaran Bio and Mana Therapeutics, with stock and/or ownership. CMB is also on the board of directors of Cabaletta Bio, with stock options, and has stock in Neximmune and Torque Therapeutics. PJH and CRYC are co-founders of Mana Therapeutics, and PJH is on the board of directors of Mana Therapeutics. PJH is also on the scientific advisory board of Cellevolve. MDK is on the scientific advisory panel of Gilead Sciences. CMB, CRYC, PJH and MS have filed a patent application based on the findings in this article., (Copyright © 2021 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Objective: Mesenchymal stromal cells have important immunomodulatory and neuroprotective properties. The aim of this study was to evaluate the feasibility of mesenchymal stromal cell administration into a cardiopulmonary bypass (CPB) circuit, including a pediatric oxygenator, and to assess the immunomodulatory response of the circulating blood prime., Methods: A bypass circuit with a pediatric oxygenator, including integral filter was primed with bank whole blood. Normal saline (control) or 120 × 10 6 mesenchymal stromal cells were injected into the venous reservoir after 80 minutes of perfusion. To assess oxygenator function, immune reaction, and cytokine/chemokine levels, the ex vivo circulation was maintained for 300 minutes after administration., Results: There were no differences in flow rate, trans-oxygenator pressure gradient, blood oxygen, and carbon dioxide levels between control and cell delivery groups. No adhesion of mesenchymal stromal cells was observed on the filter mesh by scanning electron microscopy. Lymphocyte surface marker assay found no difference in the number of B cells, T cells, or natural killer cells between the 2 groups, indicating no immunogenicity of allogeneic mesenchymal stromal cells under ex vivo CPB conditions. CPB significantly changed the level of interleukin (IL) 4, IL-6, IL-8, IP-10, macrophage colony stimulating factor, macrophage inflammatory protein-1 β , monocyte chemoattractant protein-1, and IL-1 α over time. IL-6 level was significantly increased after cell administration., Conclusions: The administration of mesenchymal stromal cells does not interfere with oxygenator function. Allogeneic mesenchymal stromal cells show no immunogenicity, and increase plasma IL-6 level during ex vivo circulation. Further investigation is necessary to determine the effect of mesenchymal stromal cell delivery through CPB during pediatric cardiac surgery., Competing Interests: Conflict of Interest Statement Dr Hanley is a cofounder and on the board of directors of Mana Therapeutics and serves on the scientific advisory board of Cellevolve. All other authors reported no conflicts of interest.

``Cellular therapies first emerged as specialized therapies only available at a few "boutique" centers worldwide. To ensure broad access to these investigational therapies-regardless of geography, demographics and other factors-more and more academic clinical trials are becoming multi-center. Such trials are typically performed with a centralized manufacturing facility receiving the starting material and shipping the final product, either fresh or cryopreserved, to the patient's institution for infusion. As these academic multi-center trials increase in number, it is critical to have procedures and training programs in place to allow these sites that are remote from the production facility to successfully participate in these trials and satisfy regulatory compliance and patient safety best practices. Based on the collective experience of the Consortium for Pediatric Cellular Immunotherapy, the authors summarize the challenges encountered by institutions in shipping and receiving the starting material and final product as well as preparing the final product for infusion. The authors also discuss best practices implemented by each of the consortia institutions to overcome these challenges., (Copyright © 2020 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

A long-standing hypothesis is that complement receptors (CRs), especially CR3, mediate sinking phagocytosis, but evidence is lacking. Alternatively, CRs have been reported to induce membrane ruffles or phagocytic cups, akin to those induced by Fcγ receptors (FcγRs), but the details of these events are unclear. Here we used real-time 3D imaging and knockout mouse models to clarify how particles (human red blood cells) are internalized by resident peritoneal F4/80 + cells (macrophages) via CRs and/or FcγRs. We first show that FcγRs mediate highly efficient, rapid (2-3 min) phagocytic cup formation, which is completely abolished by deletion or mutation of the FcR γ-chain or conditional deletion of the signal transducer Syk. FcγR-mediated phagocytic cups robustly arise from any point of cell-particle contact, including filopodia. In the absence of CR3, FcγR-mediated phagocytic cups exhibit delayed closure and become aberrantly elongated. Independent of FcgRs, CR3 mediates sporadic ingestion of complement-opsonized particles by rapid phagocytic cup-like structures, typically emanating from membrane ruffles and largely prevented by deletion of the immunoreceptor tyrosine-based activation motif (ITAM) adaptors FcR γ-chain and DAP12 or Syk. Deletion of ITAM adaptors or Syk clearly revealed that there is a slow (10-25 min) sinking mode of phagocytosis via a restricted orifice. In summary, we show that (1) CR3 indeed mediates a slow sinking mode of phagocytosis, which is accentuated by deletion of ITAM adaptors or Syk, (2) CR3 induces phagocytic cup-like structures, driven by ITAM adaptors and Syk, and (3) CR3 is involved in forming and closing FcγR-mediated phagocytic cups., (Published under license by The American Society for Biochemistry and Molecular Biology, Inc.)

A long-standing hypothesis is that complement receptors (CRs), especially CR3, mediate sinking phagocytosis, but evidence is lacking. Alternatively, CRs have been reported to induce membrane ruffles or phagocytic cups, akin to those induced by Fcγ receptors (FcγRs), but the details of these events are unclear. Here we used real-time 3D imaging and KO mouse models to clarify how particles (human red blood cells) are internalized by resident peritoneal F4/80 + cells (macrophages) via CRs and/or FcγRs. We first show that FcγRs mediate highly efficient, rapid (2-3 min) phagocytic cup formation, which is completely abolished by deletion or mutation of the FcR γ chain or conditional deletion of the signal transducer Syk. FcγR-mediated phagocytic cups robustly arise from any point of cell-particle contact, including filopodia. In the absence of CR3, FcγR-mediated phagocytic cups exhibit delayed closure and become aberrantly elongated. Independent of FcγRs, CR3 mediates sporadic ingestion of complement-opsonized particles by rapid phagocytic cup-like structures, typically emanating from membrane ruffles and largely prevented by deletion of the immunoreceptor tyrosine-based activation motif (ITAM) adaptors FcR γ chain and DAP12 or Syk. Deletion of ITAM adaptors or Syk clearly revealed that there is a slow (10-25 min) sinking mode of phagocytosis via a restricted orifice. In summary, we show that (1) CR3 indeed mediates a slow sinking mode of phagocytosis, which is accentuated by deletion of ITAM adaptors or Syk, (2) CR3 induces phagocytic cup-like structures, driven by ITAM adaptors and Syk, and (3) CR3 is involved in forming and closing FcγR-mediated phagocytic cups., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Infusion of viral-specific T cells (VSTs) is an effective treatment for viral infection after stem cell transplant. Current manufacturing approaches are rapid, but growth conditions can still be further improved. To optimize VST cell products, the authors designed a high-throughput flow cytometry-based assay using 40 cytokine combinations in a 96-well plate to fully characterize T-cell viability, function, growth and differentiation. Peripheral blood mononuclear cells (PBMCs) from six consenting donors were seeded at 100 000 cells per well with pools of cytomegalovirus peptides from IE1 and pp65 and combinations of IL-15, IL-6, IL-21, interferon alpha, IL-12, IL-18, IL-4 and IL-7. Ten-day cultures were tested by 13-color flow cytometry to evaluate viable cell count, lymphocyte phenotype, memory markers and interferon gamma (IFNγ) and tumor necrosis factor alpha (TNFα) expression. Combinations of IL-15/IL-6 and IL-4/IL-7 were optimal for the expansion of viral-specific CD3+ T cells, (18-fold and 14-fold, respectively, compared with unstimulated controls). CD8+ T cells expanded 24-fold in IL-15/IL-6 and 9-fold in IL-4/IL-7 cultures (P < 0.0001). CD4+ T cells expanded 27-fold in IL-4/IL-7 and 15-fold in IL-15/IL-6 (P < 0.0001). CD45RO+ CCR7- effector memory (CD45RO+ CCR7- CD3+), central memory (CD45RO+ CCR7+ CD3+), terminal effector (CD45RO- CCR7- CD3+), and naive (CD45RO- CCR7+ CD3+). T cells were the preponderant cells (76.8% and 72.3% in IL-15/IL-6 and IL-15/IL-7 cultures, respectively). Cells cultured in both cytokine conditions were potent, with 19.4% of CD3+ cells cultured in IL-15/IL-6 producing IFNγ (7.6% producing both TNFα and IFNγ) and 18.5% of CD3+ cells grown in IL-4/IL-7 producing IFNγ (9% producing both TNFα and IFNγ). This study shows the utility of this single-plate assay to rapidly identify optimal growth conditions for VST manufacture using only 10 7 PBMCs., (Copyright © 2020 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

T-cell responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been described in recovered patients, and may be important for immunity following infection and vaccination as well as for the development of an adoptive immunotherapy for the treatment of immunocompromised individuals. In this report, we demonstrate that SARS-CoV-2-specific T cells can be expanded from convalescent donors and recognize immunodominant viral epitopes in conserved regions of membrane, spike, and nucleocapsid. Following in vitro expansion using a good manufacturing practice-compliant methodology (designed to allow the rapid translation of this novel SARS-CoV-2 T-cell therapy to the clinic), membrane, spike, and nucleocapsid peptides elicited interferon-γ production, in 27 (59%), 12 (26%), and 10 (22%) convalescent donors (respectively), as well as in 2 of 15 unexposed controls. We identified multiple polyfunctional CD4-restricted T-cell epitopes within a highly conserved region of membrane protein, which induced polyfunctional T-cell responses, which may be critical for the development of effective vaccine and T-cell therapies. Hence, our study shows that SARS-CoV-2 directed T-cell immunotherapy targeting structural proteins, most importantly membrane protein, should be feasible for the prevention or early treatment of SARS-CoV-2 infection in immunocompromised patients with blood disorders or after bone marrow transplantation to achieve antiviral control while mitigating uncontrolled inflammation.

BK polyomavirus (BKPyV) infection is a major complication of hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT). Treatment options are limited, poorly effective, and have significant toxicities. Cellular therapy using T cells directed against BKPyV is an emerging therapy, and we report efficacy in controlling BKPyV-associated disease in highly immunocompromised patients. Virus-specific T cells (VSTs) against BKPyV were manufactured using either blood from the patient's stem cell donor (donor-derived VSTs) or from unrelated donors (third-party VSTs). VSTs were used to treat BKPyV in 38 HSCT recipients and 3 SOT recipients between June 2017 and December 2019. Overall response rate was 86% in patients treated for BK viremia, 100% in patients treated for hemorrhagic cystitis, and 87% in patients treated for both BK viremia and hemorrhagic cystitis. No infusional toxicity, de novo graft-versus-host disease, or rejection of the organ occurred attributable to the VST infusion. BKPyV-specific immune responses were demonstrated by interferon-γ production by peripheral blood mononuclear cells postinfusion in response to BKPyV antigens. VSTs are a safe and potentially effective strategy to treat BKPyV and associated symptoms in recipients of HSCT and SOT. Cellular therapy should be considered for all patients with BKPyV and underlying immune suppression at risk of complications. This trial was registered at www.clinicaltrials.gov as #NCT02532452., (© 2020 by The American Society of Hematology.)

Coronavirus disease 2019 (SARS-CoV2) is an active global health threat for which treatments are desperately being sought. Even though most people infected experience mild to moderate respiratory symptoms and recover with supportive care, certain vulnerable hosts develop severe clinical deterioration. While several drugs are currently being investigated in clinical trials, there are currently no approved treatments or vaccines for COVID-19 and hence there is an unmet need to explore additional therapeutic options. At least three inflammatory disorders or syndromes associated with immune dysfunction have been described in the context of cellular therapy. Specifically, Cytokine Release Syndrome (CRS), Immune Reconstitution Inflammatory Syndrome (IRIS), and Secondary Hemophagocytic Lymphohistiocytosis (sHLH) all have clinical and laboratory characteristics in common with COVID19 and associated therapies that could be worth testing in the context of clinical trials. Here we discuss these diseases, their management, and potential applications of these treatment in the context of COVID-19. We also discuss current cellular therapies that are being evaluated for the treatment of COVID-19 and/or its associated symptoms., (Copyright © 2020 International Society for Cell and Gene Therapy. Published by Elsevier Inc. All rights reserved.)

While antiretroviral therapy (ART) can completely suppress viremia, it is not a cure for HIV. HIV persists as a latent reservoir of infected cells, able to evade host immunity and re-seed infection following cessation of ART. Two promising immunotherapeutic strategies to eliminate both productively infected cells and reactivated cells of the reservoir are the adoptive transfer of potent HIV-specific T cells and the passive administration of HIV-specific broadly neutralizing antibodies also capable of mediating antibody-dependent cellular cytotoxicity (ADCC). The simultaneous use of both as the basis of a single therapeutic has never been explored. We therefore sought to modify HIV-specific T cells from HIV-naive donors (to allow their use in the context of allotransplant, a promising platform for sterilizing cures) so they are able to secrete a broadly neutralizing antibody (bNAb) directed against the HIV envelope to elicit ADCC. We designed an antibody construct comprising bNAb 10-1074 heavy and light chains, fused to IgG3 Fc to elicit ADCC, with truncated cluster of differentiation 19 (CD19) as a selectable marker. HIV-specific T cells were expanded from HIV-naive donors by priming with antigen-presenting cells expressing overlapping HIV antigens in the presence of cytokines. T cells retained specificity against Gag, Nef, and Pol peptides (218.55 ± 300.14 interferon γ [IFNγ] spot-forming cells [SFC]/1 × 10 5 ) following transduction (38.92 ± 25.30) with the 10-1074 antibody constructs. These cells secreted 10-1074 antibodies (139.04 ± 114.42 ng/mL). The HIV-specific T cells maintained T cell function following transduction, and the secreted 10-1074 antibody bound HIV envelope (28.13% ± 19.42%) and displayed ADCC activity (10.47% ± 4.11%). Most critically, the 10-1074 antibody-secreting HIV-specific T cells displayed superior in vitro suppression of HIV replication. In summary, HIV-specific T cells can be engineered to produce antibodies mediating ADCC against HIV envelope-expressing cells. This combined innate/adaptive approach allows for synergy between the two immune arms, broadens the target range of the immune therapy, and provides further insight into what defines an effective anti-HIV response., (© 2020 The Authors.)

Human immunodeficiency virus (HIV) has caused millions of deaths and continues to threaten the health of millions of people worldwide. Despite anti-retroviral therapy (ART) substantially alleviating severity and limiting transmission, HIV has not been eradicated and its persistence can lead to other health concerns such as cancer. The only two cases of HIV cure to date are HIV + cancer patients receiving an allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a donor with the CCR5 Δ32 mutation. While this approach has not led to such success in other patients and is not applicable to HIV + individuals without cancer, the encouraging results may point toward a breakthrough in developing a cure strategy for HIV. Adoptive transfer of virus-specific T cells (VSTs) post HSCT has been effectively used to treat and prevent reactivation of latent viral infections such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), making VSTs an attractive therapeutic to control HIV rebound. Here we will discuss the potential of using adoptive T cell therapies in combination with other treatments such as HSCT and latency reversing agents (LRAs) to achieve a functional cure for HIV., (Copyright © 2020 Lee, Keller, Hanley and Bollard.)

G protein-coupled receptor signaling is required for the navigation of immune cells along chemoattractant gradients. However, chemoattractant receptors may couple to more than one type of heterotrimeric G protein, each of which consists of a Gα, Gβ, and Gγ subunit, making it difficult to delineate the critical signaling pathways. Here, we used knockout mouse models and time-lapse microscopy to elucidate Gα and Gβ subunits contributing to complement C5a receptor-mediated chemotaxis. Complement C5a-mediated chemokinesis and chemotaxis were almost completely abolished in macrophages lacking Gnai2 (encoding Gα i2 ), consistent with a reduced leukocyte recruitment previously observed in Gnai2 -/- mice, whereas cells lacking Gnai3 (Gα i3 ) exhibited only a slight decrease in cell velocity. Surprisingly, C5a-induced Ca 2+ transients and lamellipodial membrane spreading were persistent in Gnai2 -/- macrophages. Macrophages lacking both Gnaq (Gα q ) and Gna11 (Gα 11 ) or both Gna12 (Gα 12 ) and Gna13 (Gα 13 ) had essentially normal chemotaxis, Ca 2+ signaling, and cell spreading, except Gna12 / Gna13 -deficient macrophages had increased cell velocity and elongated trailing ends. Moreover, Gnaq / Gna11 -deficient cells did not respond to purinergic receptor P2Y 2 stimulation. Genetic deletion of Gna15 (Gα 15 ) virtually abolished C5a-induced Ca 2+ transients, but chemotaxis and cell spreading were preserved. Homozygous Gnb1 (Gβ 1 ) deletion was lethal, but mice lacking Gnb2 (Gβ 2 ) were viable. Gnb2 -/- macrophages exhibited robust Ca 2+ transients and cell spreading, albeit decreased cell velocity and impaired chemotaxis. In summary, complement C5a-mediated chemotaxis requires Gα i2 and Gβ 2 , but not Ca 2+ signaling, and membrane protrusive activity is promoted by G proteins that deplete phosphatidylinositol 4,5-bisphosphate., Competing Interests: Conflict of interest—The authors declare that they have no conflicts of interest with the contents of this article., (© 2020 van den Bos et al.)

Chemotaxis is receptor-mediated guidance of cells along a chemical gradient, whereas chemokinesis is the stimulation of random cell motility by a chemical. Chemokinesis and chemotaxis are fundamental for the mobilization and deployment of immune cells. For example, chemokines (chemotactic cytokines) can rapidly recruit circulating neutrophils and monocytes to extravascular sites of inflammation. Chemoattractant receptors belong to the large family of G protein-coupled receptors. How chemoattractant (i.e., ligand) gradients direct cell migration via G protein-coupled receptor signaling is not yet fully understood. In the field of immunology, neutrophils are popular model cells for studying chemotaxis in vitro. Here we describe a real-time two-dimensional (2D) chemotaxis assay tailored for mouse resident macrophages, which have traditionally been more difficult to study. Macrophages move at a slow pace of ~1 µm/min on a 2D surface and are less well suited for point-source migration assays (e.g., migration towards the tip of a micropipette filled with chemoattractant) than neutrophils or Dictyostelium discoideum, which move an order of magnitude faster. Widely used Transwell assays are useful for studying the chemotactic activity of different substances, but do not provide information on cell morphology, velocity, or chemotactic navigation. Here we describe a time-lapse microscopy-based macrophage chemotaxis assay that allows quantification of cell velocity and chemotactic efficiency and provides a platform to delineate the transducers, signal pathways, and effectors of chemotaxis.

Background: Neurodevelopmental impairment is an important challenge for survivors after neonatal surgery with cardiopulmonary bypass (CPB). The subventricular zone, where most neural stem/progenitors originate, plays a critical role in cortical maturation of the frontal lobe. Promoting neurogenesis in the subventricular zone is therefore a potential therapeutic target for preserving cortical growth. Mesenchymal stromal cells (MSCs) promote endogenous regeneration in the rodent brain. We investigated the impact of MSC delivery through CPB on neural stem/progenitor cells and neuroblasts (ie, young neurons) in the piglet subventricular zone., Methods: Two-week-old piglets (n = 12) were randomly assigned to one of three groups: (1) control, (2) deep hypothermic circulatory arrest, and (3) circulatory arrest, followed by MSC administration. MSCs (10 × 10 6 per kg) were delivered through CPB during the rewarming period. Neural stem/progenitors, proliferating cells, and neuroblasts were identified with immunohistochemistry at 3 hours after CPB., Results: CPB-induced insults caused an increased proliferation of neural stem/progenitors (P < .05). MSC delivery reduced the acute proliferation. MSC treatment increased the number of neuroblasts in the outer region of the subventricular zone (P < .05) where they form migrating chains toward the frontal lobe. Conversely, the thickness of the neuroblast-dense band along the lateral ventricle was reduced after treatment (P < .05). These findings suggest that MSC treatment changes neuroblast distribution within the subventricular zone., Conclusions: MSC delivery through CPB has the potential to mitigate effects of CPB on neural stem/progenitor cells and to promote migration of neuroblasts. Further investigation is necessary to determine the long-term effect of MSC treatment during CPB on postnatal neurogenesis., (Copyright © 2020 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Children with ataxia telangiectasia (AT), a primary immunodeficiency caused by mutations in ATM, which is critical for repairing DNA defects, are at risk for the development of hematologic malignancy, frequently driven by infection with Epstein-Barr virus (EBV). Conventional chemotherapy is poorly tolerated by patients with AT, with excessive toxicity even when doses are reduced. Here, we report on two patients with AT and EBV-positive neoplasms who were treated with EBV-targeted viral-specific T cells (VST). One patient had a prolonged complete response to VSTs while the other had a partial response. Therapy was well tolerated without infusion toxicity or graft-versus-host disease., (© 2019 Wiley Periodicals, Inc.)

Background: Chronic norovirus infection in immunocompromised patients can be severe, and presently there is no effective treatment. Adoptive transfer of virus-specific T cells has proven to be safe and effective for the treatment of many viral infections, and this could represent a novel treatment approach for chronic norovirus infection. Hence, we sought to generate human norovirus-specific T cells (NSTs) that can recognize different viral sequences., Methods: Norovirus-specific T cells were generated from peripheral blood of healthy donors by stimulation with overlapping peptide libraries spanning the entire coding sequence of the norovirus genome., Results: We successfully generated T cells targeting multiple norovirus antigens with a mean 4.2 ± 0.5-fold expansion after 10 days. Norovirus-specific T cells comprised both CD4+ and CD8+ T cells that expressed markers for central memory and effector memory phenotype with minimal expression of coinhibitory molecules, and they were polyfunctional based on cytokine production. We identified novel CD4- and CD8-restricted immunodominant epitopes within NS6 and VP1 antigens. Furthermore, NSTs showed a high degree of cross-reactivity to multiple variant epitopes from clinical isolates., Conclusions: Our findings identify immunodominant human norovirus T-cell epitopes and demonstrate that it is feasible to generate potent NSTs from third-party donors for use in antiviral immunotherapy., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Virus-specific T cells allow targeting of multiple pathogens in patients after hematopoietic stem cell transplantation and have demonstrated potential efficacy for cytomegalovirus, Epstein-Barr Virus, and adenovirus. Novel targets may include BK virus, JC virus, varicella zoster virus, human herpesvirus 6, Aspergillus, human parainfluenza virus-3, herpes simplex virus Type I, Zika virus, and mycobacteria. Generation of patient-specific products and third-party products may expand feasibility of therapy., (© 2019 AABB.)

Class IX myosins are simultaneously motor and signaling molecules. In addition to myosin class-specific functions of the tail region, they feature unique motor properties. Within their motor region they contain a long insertion with a calmodulin- and a F-actin-binding site. The rate-limiting step in the ATPase cycle is ATP hydrolysis rather than, typical for other myosins, the release of either product. This means that class IX myosins spend a large fraction of their cycle time in the ATP-bound state, which is typically a low F-actin affinity state. Nevertheless, class IX myosins in the ATP-bound state stochastically switch between a low and a high F-actin affinity state. Single motor domains even show characteristics of processive movement towards the plus end of actin filaments. The insertion thereby acts as an actin tether. The motor domain transports as intramolecular cargo a signaling Rho GTPase-activating protein domain located in the tail region. Rho GTPase-activating proteins catalyze the conversion of active GTP-bound Rho to inactive GDP-bound Rho by stimulating GTP hydrolysis. In cells, Rho activity regulates actin cytoskeleton organization and actomyosin II contractility. Thus, class IX myosins regulate cell morphology, cell migration, cell-cell junctions and membrane trafficking. These cellular functions affect embryonic development, adult organ homeostasis and immune responses. Human diseases associated with mutations in the two class IX myosins, Myo9a and Myo9b, have been identified, including hydrocephalus and congenital myasthenic syndrome in connection with Myo9a and autoimmune diseases in connection with Myo9b.

Purpose of Review: The US Food and Drug Administration (FDA) approved two commercially available chimeric antigen receptor (CAR) T cell therapies for the treatment of relapsed B cell acute lymphoblastic leukemia (B-ALL) children and young adults less than 25 years of age and non-Hodgkin lymphoma in adults after promising results from early-phase single and multi-institutional clinical trials. In this review, we provide an overview of the practical aspects of a chimeric antigen T cell receptor (CAR-T) program development and the steps necessary for its successful implementation., Recent Findings: CAR-T therapy is a complex process and poses significant challenges as institutions prepare to deliver this therapy as a standard of care for the eligible patients. It requires a rigorous infrastructure with specific clinical, administrative, and regulatory demands. Institutions that led the clinical trials for CAR-T have adopted various approaches to integrate commercial CAR-T products into their program. Delivering commercial CAR-T cells outside the scope of clinical trials requires careful planning, allocation of resources, and utilization of existing infrastructure. Institutions may need to adapt the existing recommendations and guidelines and tailor them to meet the needs of their program and ensure appropriate financial reimbursement for this expensive but promising immunotherapy.

Although anti-retroviral therapy (ART) is successful in suppressing HIV-1 replication, HIV latently infected reservoirs are not eliminated, representing a major hurdle in efforts to eradicate the virus. Current strategies to eradicate HIV involve two steps: (1) the reactivation of latently infected cells with latency reversing agents (LRAs) to expose persisting HIV, and (2) the elimination of these cells with immune effectors while continuing ART to prevent reinfection. HIV-specific T cells (HSTs) can kill reactivated HIV-infected cells and are currently being evaluated in early-stage immunotherapy trials. HIV can mutate sequences in T cell epitopes and evade T cell-mediated killing of HIV-infected cells. However, by directing T cells to target multiple conserved, non-escaped HIV epitopes, the opportunity for viral escape can be reduced. Using a good manufacturing practice (GMP)-compliant platform, we manufactured HSTs against non-escape epitope targets (HST-NEETs) from HIV + and HIV-seronegative donors. HST-NEETs expanded to clinically relevant numbers, lysed autologous antigen-pulsed targets, and showed a polyfunctional pro-inflammatory cytokine response. Notably, HST-NEETs recognized multiple conserved, non-escaped HIV epitopes and their common variants. We propose that HST-NEETs could be used to eliminate reactivated virus from latently infected cells in HIV + individuals following LRA treatment. Additionally, HST-NEETs derived from HIV-negative individuals could be used post-transplant for HIV + individuals with hematologic malignancies to augment anti-viral immunity and destroy residual infected cells., (© 2019 The Author(s).)

Viral infections are a serious cause of morbidity and mortality following haematopoietic stem cell transplantation (HSCT). Adoptive cellular therapy with virus-specific T cells (VSTs) has been successful in preventing or treating targeted viruses in prior studies, but the composition of ex vivo expanded VST and the critical cell populations that mediate antiviral activity in vivo are not well defined. We utilized deep sequencing of the T-cell receptor beta chain (TCRB) in order to classify and track VST populations in 12 patients who received VSTs following HSCT to prevent or treat viral infections. TCRB sequencing was performed on sorted VST products and patient peripheral blood mononuclear cells samples. TCRB diversity was gauged using the Shannon entropy index, and repertoire similarity determined using the Morisita-Horn index. Similarity indices reflected an early change in TCRB diversity in eight patients, and TCRB clonotypes corresponding to targeted viral epitopes expanded in eight patients. TCRB repertoire diversity increased in nine patients, and correlated with cytomegalovirus (CMV) viral load following VST infusion (P = 0·0071). These findings demonstrate that allogeneic VSTs can be tracked via TCRB sequencing, and suggests that T-cell receptor repertoire diversity may be critical for the control of CMV reactivation after HSCT., (© 2019 British Society for Haematology and John Wiley & Sons Ltd.)

Background: Medulloblastoma (MB), the most common pediatric brain cancer, presents with a poor prognosis in a subset of patients with high risk disease, or at recurrence, where current therapies are ineffective. Cord blood (CB) natural killer (NK) cells may be promising off-the-shelf effector cells for immunotherapy due to their recognition of malignant cells without the need for a known target, ready availability from multiple banks, and their potential to expand exponentially. However, they are currently limited by immune suppressive cytokines secreted in the MB tumor microenvironment including Transforming Growth Factor β (TGF-β). Here, we address this challenge in in vitro models of MB., Methods: CB-derived NK cells were modified to express a dominant negative TGF-β receptor II (DNRII) using retroviral transduction. The ability of transduced CB cells to maintain function in the presence of medulloblastoma-conditioned media was then assessed., Results: We observed that the cytotoxic ability of nontransduced CB-NK cells was reduced in the presence of TGF-β-rich, medulloblastoma-conditioned media (21.21 ± 1.19% killing at E:T 5:1 in the absence vs. 14.98 ± 2.11% in the presence of medulloblastoma-conditioned media, n = 8, p = 0.02), but was unaffected in CB-derived DNRII-transduced NK cells (21.11 ± 1.84% killing at E:T 5:1 in the absence vs. 21.81 ± 3.37 in the presence of medulloblastoma-conditioned media, n = 8, p = 0.85. We also observed decreased expression of CCR2 in untransduced NK cells (mean CCR2 MFI 826 ± 117 in untransduced NK + MB supernatant from mean CCR2 MFI 1639.29 ± 215 in no MB supernatant, n = 7, p = 0.0156), but not in the transduced cells. Finally, we observed that CB-derived DNRII-transduced NK cells may protect surrounding immune cells by providing a cytokine sink for TGF-β (decreased TGF-β levels of 610 ± 265 pg/mL in CB-derived DNRII-transduced NK cells vs. 1817 ± 342 pg/mL in untransduced cells; p = 0.008)., Conclusions: CB NK cells expressing a TGF-β DNRII may have a functional advantage over unmodified NK cells in the presence of TGF-β-rich MB, warranting further investigation on its potential applications for patients with medulloblastoma.

Purpose: Tumor-associated antigen cytotoxic T cells (TAA-Ts) represent a new, potentially effective and nontoxic therapeutic approach for patients with relapsed or refractory solid tumors. In this first-in-human trial, we investigated the safety of administering TAA-Ts that target Wilms tumor gene 1, preferentially expressed antigen of melanoma, and survivin to patients with relapsed/refractory solid tumors., Materials and Methods: TAA-T products were generated from autologous peripheral blood and infused over three dose levels: 1, 2, and 4 × 10 7 cells/m 2 . Patients were eligible for up to eight infusions administered 4 to 7 weeks apart. We assessed dose limiting toxicity during the first 45 days after infusion. Disease response was determined within the context of a phase I trial., Results: There were no dose-limiting toxicities. Of 15 evaluable patients, 11 (73%) with stable disease or better at day 45 postinfusion were defined as responders. Six responders remain without progression at a median of 13.9 months (range, 4.1 to 19.9 months) after initial TAA-Ts. Patients who were treated at the highest dose level showed the best clinical outcomes, with a 6-month progression-free survival of 73% after TAA-T infusion compared with a 38% 6-month progression-free survival with prior therapy. Antigen spreading and a reduction in circulating tumor-associated antigens using digital droplet polymerase chain reaction was observed in patients after TAA-T infusion., Conclusion: TAA-Ts safely induced disease stabilization, prolonged time to progression, and were associated with antigen spreading and a reduction in circulating tumor-associated antigen DNA levels in patients with relapsed/refractory solid tumors without lymphodepleting chemotherapy before infusion. TAA-Ts are a promising new treatment approach for patients with solid tumors.

Background: Zika virus (ZIKV) infection can cause severe birth defects in newborns with no effective currently available treatment. Adoptive transfer of virus-specific T cells has proven to be safe and effective for the prevention or treatment of many viral infections, and could represent a novel treatment approach for patients with ZIKV infection. However, extending this strategy to the ZIKV setting has been hampered by limited data on immunogenic T-cell antigens within ZIKV. Hence, we have generated ZIKV-specific T cells and characterized the cellular immune responses against ZIKV antigens., Methods: T-cell products were generated from peripheral blood of ZIKV-exposed donors, ZIKV-naive adult donors and umbilical cord blood by stimulation with pentadecamer (15mer) overlapping peptide libraries spanning four ZIKV polyproteins (C, M, E and NS1) using a Good Manufacturing Practice-compliant protocol., Results: We successfully generated T cells targeting ZIKV antigens with clinically relevant numbers. The ex vivo-expanded T cells comprised both CD4 + and CD8 + T cells that were able to produce Th1-polarized effector cytokines and kill ZIKV-infected HLA-matched monocytes, confirming functionality of this unique T-cell product as a potential "off-the-shelf" therapeutic. Epitope mapping using peptide arrays identified several novel HLA class I and class II-restricted epitopes within NS1 antigen, which is essential for viral replication and immune evasion., Discussion: Our findings demonstrate that it is feasible to generate potent ZIKV-specific T cells from a variety of cell sources including virus naïve donors for future clinical use in an "off-the-shelf" setting., (Copyright © 2019 International Society for Cell and Gene Therapy. Published by Elsevier Inc. All rights reserved.)