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The T cell response to cancer controls disease progression and response to immunotherapy 1-3 . Despite extensive knowledge regarding CD8 T cells, how CD4 T cells contribute to this process is less well understood. Here we identified a population of PD1 + TCF1 + CD4 T cells with stem-like properties that are capable of self-renewal and differentiation into canonical CD4 effector cells. Primarily residing in tumour-draining lymph nodes (TDLNs), these tumour-specific CD4 T cells are restricted by T regulatory (T reg ) cells to a stem-like fate that predominantly generated induced T reg (iT reg ) cells, limiting effector CD8 T cell responses to the tumour. By contrast, upon T reg depletion, stem-like CD4 T cells differentiated into T helper 1 (T H 1) cells, and via IFNγ production induced robust effector differentiation from TCF1 + CD8 T cells in TDLNs, a state we defined as 'active'. Notably, enforcing TBET expression in transferred stem-like CD4 T cells was sufficient to overcome the established restricted T cell state. Despite the presence of T reg cells, endogenous stem-like CD4 T cells actively generated T H 1 cells, which were required to restore TDLN effector CD8 T cell differentiation, enhance tumour control and rescue response to immunotherapy. In agreement, T H 1 differentiation in patients with kidney cancer predicted successful immunotherapy responses and improved progression-free survival. Together, these findings identify a stem-like CD4 T cell population that through alternative differentiation fates controls the switch between restricted and active T cell states with implications for cancer immunotherapies., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

The direct alloresponse, pivotal in transplant rejection, occurs when recipient T cells recognize intact allogeneic peptide-major histocompatibility complex (pMHC) complexes. Despite extensive research, our understanding of alloreactive CD8 + T cells against an individual MHC allele in humans remains limited, especially their precursor frequency, MHC specificity, and peptide specificity. By using K562 cell-based artificial antigen-presenting cells expressing human leukocyte antigen (HLA)-A∗01:01, HLA-A∗02:01, or HLA-A∗03:01, we determined that the precursor frequency of alloreactive CD8 + T cells against a single MHC allele ranges from 0.1% to 0.5%. Further, these cells exhibited MHC specificity regarding proliferation, activation, interferon gamma secretion, and cytolytic ability, with limited crossreactivity toward nontargeted MHC alleles. Focusing on anti-A2 alloreactive CD8 + T cells, we developed a peptide-exchangeable artificial antigen-presenting cell that displays selected peptides on HLA-A∗02:01. From a set of 95 computationally curated A2-restricted peptides most abundant in renal tubular cells, we identified 2 immunogenic kidney peptides across multiple donors. Overall, our findings significantly enhance the understanding of direct alloresponse and provide a toolkit for future mechanistic studies and reproducible patient monitoring., Competing Interests: Declaration of competing interest The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Human immunodeficiency virus (HIV) cure efforts are increasingly focused on harnessing CD8 + T cell functions, which requires a deeper understanding of CD8 + T cells promoting HIV control. Here we identifiy an antigen-responsive TOX hi TCF1 + CD39 + CD8 + T cell population with high expression of inhibitory receptors and low expression of canonical cytolytic molecules. Transcriptional analysis of simian immunodeficiency virus (SIV)-specific CD8 + T cells and proteomic analysis of purified CD8 + T cell subsets identified TOX hi TCF1 + CD39 + CD8 + T cells as intermediate effectors that retained stem-like features with a lineage relationship with terminal effector T cells. TOX hi TCF1 + CD39 + CD8 + T cells were found at higher frequency than TCF1 - CD39 + CD8 + T cells in follicular microenvironments and were preferentially located in proximity of SIV-RNA + cells. Their frequency was associated with reduced plasma viremia and lower SIV reservoir size. Highly similar TOX hi TCF1 + CD39 + CD8 + T cells were detected in lymph nodes from antiretroviral therapy-naive and antiretroviral therapy-suppressed people living with HIV, suggesting this population of CD8 + T cells contributes to limiting SIV and HIV persistence., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

T lymphocytes expressing CD57 and lacking costimulatory receptors CD27/CD28 have been reported to accumulate with aging, chronic infection, and cancer. These cells are described as senescent, with inability to proliferate but enhanced cytolytic and cytokine-producing capacity. However, robust functional studies on these cells taken directly from cancer patients are lacking. We isolated these T cells and their CD27/28+ counterparts from blood and tumor samples of 50 patients with previously untreated head and neck cancer. Functional studies confirmed that these cells have enhanced ability to degranulate and produce IFN-γ. They also retain the ability to proliferate, thus are not senescent. These data suggest that CD27/28-CD57+ CD8+ T cells are a subset of highly differentiated, CD45RA+ effector memory (T EMRA ) cells with retained proliferative capacity. Patients with > 34% of these cells among CD8+ T cells in the blood had a higher rate of locoregional disease relapse, suggesting these cells may have prognostic significance., Competing Interests: NCS discloses consulting fees from Sensorion, Regeneron, and GeoVax in addition to research funding from Astex Pharmaceuticals. The authors have no conflicting financial interests related to this work., (© 2024 The Author(s). Published with license by Taylor & Francis Group, LLC.)

CD8 T cells play an essential role in antitumor immunity and chronic viral infections. Recent findings have delineated the differentiation pathway of CD8 T cells in accordance with the progenitor-progeny relationship of TCF1 + stem-like and Tim-3 + TCF1 - more differentiated T cells. Here, we investigated the characteristics of stem-like and differentiated CD8 T cells isolated from several murine tumor models and human lung cancer samples in terms of phenotypic and transcriptional features as well as their location compared to virus-specific CD8 T cells in the chronically lymphocytic choriomeningitis virus (LCMV)-infected mice. We found that CD8 tumor-infiltrating lymphocytes (TILs) in both murine and human tumors exhibited overall similar phenotypic and transcriptional characteristics compared to corresponding subsets in the spleen of chronically infected mice. Moreover, stem-like CD8 TILs exclusively responded and produced effector-like progeny CD8 T cells in vivo after antigenic restimulation, confirming their lineage relationship and the proliferative potential of stem-like CD8 TILs. Most importantly, similar to the preferential localization of PD-1 + stem-like CD8 T cells in T cell zones of the spleen during chronic LCMV infection, we found that the PD-1 + stem-like CD8 TILs in lung cancer samples are preferentially located not in the tumor parenchyma but in tertiary lymphoid structures (TLSs). The stem-like CD8 T cells are present in TLSs located within and at the periphery of the tumor, as well as in TLSs closely adjacent to the tumor parenchyma. These findings suggest that TLSs provide a protective niche to support the quiescence and maintenance of stem-like CD8 T cells in the tumor.

Increased demand for novel, highly effective vaccination strategies necessitates a better understanding of long-lived memory CD8 T cell differentiation. To achieve this understanding, we used the mouse model of acute lymphocytic choriomeningitis virus (LCMV) infection. We reexamined classical memory CD8 T cell subsets and performed in-depth, longitudinal analysis of their phenotype, transcriptional programming, and anatomic location within the spleen. All analyses were performed at multiple time points from 8 days to 1 year postinfection. Memory subsets are conventionally defined by their expression of KLRG1 and IL-7Rα, as follows: KLRG1 + IL-7Rα - terminal effectors (TEs) and KLRG1 - IL-7Rα + memory precursors (MPs). But we also characterized a third KLRG1 + IL-7Rα + subset which we refer to as KLRG1 + MPs. In these analyses, we defined a comprehensive memory phenotype that is associated with higher levels of CD28 expression. We also demonstrated that MPs, KLRG1 + MPs, and TEs have distinct localization programs within the spleen. We found that MPs became preferentially enriched in the white pulp as early as 1 to 2 weeks postinfection, and their predominance in the white pulp was maintained throughout the course of a year. On the other hand, KLRG1 + MPs and TEs localized to the red pulp just as early, and they consistently localized to the red pulp thereafter. These findings indicate that location may be crucial for memory formation and that white pulp-derived signals may contribute to long-term memory survival. Achieving robust memory responses following vaccination may require more deliberate consideration of which memory phenotypes are induced, as well as where they traffic, as these factors could impact their longevity. IMPORTANCE CD8 T cells play a critical role in viral immunity and it is important to understand how memory cells are formed and what processes lead to their long-term maintenance. Here, we use a mouse model of acute infection to perform an in-depth, longitudinal analysis of memory CD8 T cell differentiation, examining the phenotype and location of memory cells out to 1 year postinfection.

Invariant natural killer T cells (iNKT cells) express a semi-invariant T cell receptor that recognizes certain glycolipids (including α-galactosylceramide, αGC) bound to CD1d, and can induce potent antitumor responses. Here, we assessed whether αGC could enhance the efficacy of a GM-CSF-producing tumor cell vaccine in the transgenic SV40 T antigen-driven TRAMP prostate cancer model. In healthy mice, we initially found that optimal T cell responses were obtained with αGC-pulsed TRAMP-C2 cells secreting GM-CSF and milk fat globule epidermal growth factor protein-8 (MFG-E8) with an RGD to RGE mutation (GM-CSF/RGE TRAMP-C2), combined with systemic low dose IL-12. In a therapeutic model, transgenic TRAMP mice were then castrated at ~ 20 weeks, followed by treatment with the combination vaccine. Untreated mice succumbed to tumor by ~ 40 weeks, but survival was markedly prolonged by vaccine treatment, with most mice surviving past 80 weeks. Prostates in the treated mice were heavily infiltrated with T cells and iNKT cells, which both secreted IFNγ in response to tumor cells. The vaccine was not effective if the αGC, IL-12, or GM-CSF secretion was eliminated. Finally, immunized mice were fully resistant to challenge with TRAMP-C2 cells. Together these findings support further development of therapeutic vaccines that exploit iNKT cell activation., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Recent studies have defined a novel population of PD-1+ TCF-1+ stem-like CD8 T cells in chronic infections and cancer. These quiescent cells reside in lymphoid tissues, are critical for maintaining the CD8 T cell response under conditions of persistent antigen, and provide the proliferative burst after PD-1 blockade. Here we examined the role of TGF-β in regulating the differentiation of virus-specific CD8 T cells during chronic LCMV infection of mice. We found that TGF-β signaling was not essential for the generation of the stem-like CD8 T cells but was critical for maintaining the stem-like state and quiescence of these cells. TGF-β regulated the unique transcriptional program of the stem-like subset, including upregulation of inhibitory receptors specifically expressed on these cells. TGF-β also promoted the terminal differentiation of exhausted CD8 T cells by suppressing the effector-associated program. Together, the absence of TGF-β signaling resulted in significantly increased accumulation of effector-like CD8 T cells. These findings have implications for immunotherapies in general and especially for T cell therapy against chronic infections and cancer., (© 2022 Hu et al.)

Expansion and differentiation of antigen-experienced PD-1 + TCF-1 + stem-like CD8 + T cells into effector cells is critical for the success of immunotherapies based on PD-1 blockade 1-4 . Hashimoto et al. have shown that, in chronic infections, administration of the cytokine interleukin (IL)-2 triggers an alternative differentiation path of stem-like T cells towards a distinct population of 'better effector' CD8 + T cells similar to those generated in an acute infection 5 . IL-2 binding to the IL-2 receptor α-chain (CD25) was essential in triggering this alternative differentiation path and expanding better effectors with distinct transcriptional and epigenetic profiles. However, constitutive expression of CD25 on regulatory T cells and some endothelial cells also contributes to unwanted systemic effects from IL-2 therapy. Therefore, engineered IL-2 receptor β- and γ-chain (IL-2Rβγ)-biased agonists are currently being developed 6-10 . Here we show that IL-2Rβγ-biased agonists are unable to preferentially expand better effector T cells in cancer models and describe PD1-IL2v, a new immunocytokine that overcomes the need for CD25 binding by docking in cis to PD-1. Cis binding of PD1-IL2v to PD-1 and IL-2Rβγ on the same cell recovers the ability to differentiate stem-like CD8 + T cells into better effectors in the absence of CD25 binding in both chronic infection and cancer models and provides superior efficacy. By contrast, PD-1- or PD-L1-blocking antibodies alone, or their combination with clinically relevant doses of non-PD-1-targeted IL2v, cannot expand this unique subset of better effector T cells and instead lead to the accumulation of terminally differentiated, exhausted T cells. These findings provide the basis for the development of a new generation of PD-1 cis-targeted IL-2R agonists with enhanced therapeutic potential for the treatment of cancer and chronic infections., (© 2022. The Author(s).)

Combination therapy with PD-1 blockade and IL-2 is highly effective during chronic lymphocytic choriomeningitis virus infection 1 . Here we examine the underlying basis for this synergy. We show that PD-1 + IL-2 combination therapy, in contrast to PD-1 monotherapy, substantially changes the differentiation program of the PD-1 + TCF1 + stem-like CD8 +  T cells and results in the generation of transcriptionally and epigenetically distinct effector CD8 +  T cells that resemble highly functional effector CD8 +  T cells seen after an acute viral infection. The generation of these qualitatively superior CD8 + T cells that mediate viral control underlies the synergy between PD-1 and IL-2. Our results show that the PD-1 + TCF1 + stem-like CD8 + T cells, also referred to as precursors of exhausted CD8 + T cells, are not fate-locked into the exhaustion program and their differentiation trajectory can be changed by IL-2 signals. These virus-specific effector CD8 + T cells emerging from the stem-like CD8 + T cells after combination therapy expressed increased levels of the high-affinity IL-2 trimeric (CD25-CD122-CD132) receptor. This was not seen after PD-1 blockade alone. Finally, we show that CD25 engagement with IL-2 has an important role in the observed synergy between IL-2 cytokine and PD-1 blockade. Either blocking CD25 with an antibody or using a mutated version of IL-2 that does not bind to CD25 but still binds to CD122 and CD132 almost completely abrogated the synergistic effects observed after PD-1 + IL-2 combination therapy. There is considerable interest in PD-1 + IL-2 combination therapy for patients with cancer 2,3 , and our fundamental studies defining the underlying mechanisms of how IL-2 synergizes with PD-1 blockade should inform these human translational studies., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: This study was aimed at assessing the associations of sarcopenia, muscle density, adiposity, and inflammation with overall survival (OS) after cytoreductive nephrectomy (CN) for metastatic renal cell carcinoma., Methods: In all, 158 patients undergoing CN from 2001 to 2014 had digitized preoperative imaging for tissue segmentation via Slice-O-Matic software (version 5.0) at the mid-L3 level. The skeletal muscle index was calculated with the skeletal muscle area (cm 2 ) normalized for height (m 2 ), and the skeletal muscle density (SMD) was calculated with average Hounsfield units. Adiposity was measured with the cross-sectional area (cm 2 ) of visceral, subcutaneous, and intramuscular adiposity compartments and was similarly normalized for height. The average fat density was obtained in Hounsfield units. OS was estimated with the Kaplan-Meier method. Associations between body composition, inflammation metrics, and relevant clinicopathology and OS were assessed with univariable and multivariate Cox analyses., Results: Seventy-six of the 158 patients (48%) were sarcopenic. Sarcopenia was associated with elevated neutrophil to lymphocyte ratios (NLRs; P = .02), increased age (P = .001), lower body mass indices (P = .009), greater modified Motzer scores (P = .019), and lower SMD (P = .006). The median OS was 15.0 and 29.4 months for sarcopenic and nonsarcopenic patients, respectively (P = .04). Elevated inflammation (NLR or C-reactive protein), in addition to sarcopenia, was independently associated with OS, with an elevated NLR ≥ 3.5 and sarcopenia associated with the poorest OS at 10.2 months. No associations were observed between measurements of muscle density or adiposity and OS., Conclusions: Sarcopenia and measures of high systemic inflammation are additively associated with inferior OS after CN and may be of use in preoperative risk stratification., Lay Summary: Body composition and sarcopenia (a deficiency in skeletal musculature) have been shown to affect outcomes in cancer. We found that sarcopenic patients had poor survival in comparison with nonsarcopenic patients in the setting of metastatic renal cell carcinoma (mRCC). Patients with both elevated inflammation and sarcopenia had the poorest survival. Sarcopenia is an objective measure of nutrition that can assist in therapeutic counseling and decision-making for individualized treatment in mRCC., (© 2022 American Cancer Society.)

The pool of memory CD8 T cells is comprised of highly specialized subpopulations of cells with both shared and distinct functions. The ongoing study of T-cell memory is focused on how these different subpopulations arise, how the cells are maintained over the life of the host, and how the cells protect a host against reinfection. As a field we have used the convenience of a narrow range of surface markers to define and study these memory T-cell subsets. However, as we learn more about these cells, it is becoming clear that these broad definitions are insufficient to capture the complexity of the CD8 memory T-cell pool, and an updated definition of these cellular states are needed. Here, we discuss data that have recently arisen that highlight the difficulty in using surface markers to functionally characterize CD8 T-cell populations, and the possibility of using the epigenetic state of cells to more clearly define the functional capacity of CD8 memory T-cell subsets., (Copyright © 2022 Cold Spring Harbor Laboratory Press; all rights reserved.)

Background: Several immune checkpoint inhibitors (ICIs) are approved for the treatment of advanced urothelial carcinoma (UC). There are limited biomarkers for ICI-treated patients with UC. We investigated the association between body composition and clinical outcomes in ICI-treated UC patients., Materials and Methods: We conducted a retrospective analysis of 70 ICI-treated patients with advanced UC at Winship Cancer Institute from 2015 to 2020. Baseline computed tomography images within 2 months of ICI initiation were collected at mid-L3 and muscle and fat compartments (subcutaneous, intermuscular, and visceral) were segmented using SliceOMatic v5.0 (TomoVision, Magog, Canada). A prognostic body composition risk score (high: 0-1, intermediate: 2-3, or low-risk: 4) was created based on the β coefficient from the multivariate Cox model (MVA) following best-subset variable selection. Our body composition risk score was skeletal muscle index (SMI) + 2 × attenuated skeletal muscle (SM) mean + visceral fat index (VFI). Concordance statistics (C-statistics) were used to quantify the discriminatory magnitude of the predictive model., Results: Most patients (70%) were men and the majority received ICIs in the second- (46%) or third-line (21%) setting. High-risk patients had significantly shorter overall survival (OS; hazard ratio [HR], 6.72; p < .001), progression-free survival (HR, 5.82; p < .001), and lower chance of clinical benefit (odds ratio [OR], 0.02; p = .003) compared with the low-risk group in MVA. The C-statistics for our body composition risk group and myosteatosis analyses were higher than body mass index for all clinical outcomes., Conclusion: Body composition variables such as SMI, SM mean, and VFI may be prognostic and predictive of clinical outcomes in ICI-treated patients with UC. Larger, prospective studies are warranted to validate this hypothesis-generating data., Implications for Practice: This study developed a prognostic body composition risk scoring system using radiographic biomarkers for patients with bladder cancer treated with immunotherapy. The study found that the high-risk patients had significantly worse clinical outcomes. Notably, the study's model was better at predicting outcomes than body mass index. Importantly, these results suggest that radiographic measures of body composition should be considered for inclusion in updated prognostic models for patients with urothelial carcinoma treated with immunotherapy. These findings are useful for practicing oncologists in the academic or community setting, particularly given that baseline imaging is routine for patients starting on treatment with immunotherapy., (© 2021 AlphaMed Press.)

Plasmablasts represent a specialized class of antibody-secreting effector B cells that transiently appear in blood circulation following infection or vaccination. The expansion of these cells generally tends to be massive in patients with systemic infections such as dengue or Ebola that cause hemorrhagic fever. To gain a detailed understanding of human plasmablast responses beyond antibody expression, here, we performed immunophenotyping and RNA sequencing (RNA-seq) analysis of the plasmablasts from dengue febrile children in India. We found that plasmablasts expressed several adhesion molecules and chemokines or chemokine receptors that are involved in endothelial interactions or homing to inflamed tissues, including skin, mucosa, and intestine, and upregulated the expression of several cytokine genes that are involved in leukocyte extravasation and angiogenesis. These plasmablasts also upregulated the expression of receptors for several B-cell prosurvival cytokines that are known to be induced robustly in systemic viral infections such as dengue, some of which generally tend to be relatively higher in patients manifesting hemorrhage and/or shock than in patients with mild febrile infection. These findings improve our understanding of human plasmablast responses during the acute febrile phase of systemic dengue infection. IMPORTANCE Dengue is globally spreading, with over 100 million clinical cases annually, with symptoms ranging from mild self-limiting febrile illness to more severe and sometimes life-threatening dengue hemorrhagic fever or shock, especially among children. The pathophysiology of dengue is complex and remains poorly understood despite many advances indicating a key role for antibody-dependent enhancement of infection. While serum antibodies have been extensively studied, the characteristics of the early cellular factories responsible for antibody production, i.e., plasmablasts, are only beginning to emerge. This study provides a comprehensive understanding of the transcriptional profiles of human plasmablasts from dengue patients.

Background: Immune checkpoint inhibitors (ICIs) are an important treatment for metastatic renal cell carcinoma (mRCC). These agents may cause immune-related adverse events (irAEs), and the relationship between irAEs and outcomes is poorly understood. We investigated the association between irAEs and clinical outcomes in patients with mRCC treated with ICIs., Methods: We performed a retrospective study of 200 patients with mRCC treated with ICIs at Winship Cancer Institute from 2015 to 2020. Data on irAEs were collected from clinic notes and laboratory values and grades were determined using Common Terminology Criteria in Adverse Events version 5.0. The association with overall survival (OS) and progression-free survival (PFS) was modeled by Cox proportional hazards model. Logistic regression models were used to define odds ratios (ORs) for clinical benefit (CB). Landmark analysis and extended Cox models were used to mitigate lead-time bias by treating irAEs as a time-varying covariate., Results: Most patients (71.0%) were male, and one-third of patients (33.0%) experienced at least one irAE, most commonly involving the endocrine glands (13.0%), gastrointestinal tract (10.5%), or skin (10.0%). Patients who experienced irAEs had significantly longer OS (hazard ratio [HR], 0.52; p = .013), higher chance of CB (OR, 2.10; p = .023) and showed a trend toward longer PFS (HR, 0.71; p = .065) in multivariate analysis. Patients who had endocrine irAEs, particularly thyroid irAEs, had significantly longer OS and PFS and higher chance of CB. In a 14-week landmark analysis, irAEs were significantly associated with prolonged OS (p = .045). Patients who experienced irAEs had significantly longer median OS (44.5 vs. 18.2 months, p = .005) and PFS (7.5 vs. 3.6 months, p = .003) without landmark compared with patients who did not., Conclusion: We found that patients with mRCC treated with ICIs who experienced irAEs, particularly thyroid irAEs, had significantly improved clinical outcomes compared with patients who did not have irAEs. This suggests that irAEs may be effective clinical biomarkers in patients with mRCC treated with ICIs. Future prospective studies are warranted to validate these findings., Implications for Practice: This study found that early onset immune-related adverse events (irAEs) are associated with significantly improved clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with immune checkpoint inhibitors (ICIs). In this site-specific irAE analysis, endocrine irAEs, particularly thyroid irAEs, were significantly associated with improved clinical outcomes. These results have implications for practicing medical oncologists given the increasing use of ICIs for the treatment of mRCC. Importantly, these results suggest that early irAEs and thyroid irAEs at any time on treatment with ICIs may be clinical biomarkers of clinical outcomes in patients with mRCC treated with ICIs., (© 2021 AlphaMed Press.)

Tumours often contain B cells and plasma cells but the antigen specificity of these intratumoral B cells is not well understood 1-8 . Here we show that human papillomavirus (HPV)-specific B cell responses are detectable in samples from patients with HPV-positive head and neck cancers, with active production of HPV-specific IgG antibodies in situ. HPV-specific antibody secreting cells (ASCs) were present in the tumour microenvironment, with minimal bystander recruitment of influenza-specific cells, suggesting a localized and antigen-specific ASC response. HPV-specific ASC responses correlated with titres of plasma IgG and were directed against the HPV proteins E2, E6 and E7, with the most dominant response against E2. Using intratumoral B cells and plasma cells, we generated several HPV-specific human monoclonal antibodies, which exhibited a high degree of somatic hypermutation, consistent with chronic antigen exposure. Single-cell RNA sequencing analyses detected activated B cells, germinal centre B cells and ASCs within the tumour microenvironment. Compared with the tumour parenchyma, B cells and ASCs were preferentially localized in the tumour stroma, with well-formed clusters of activated B cells indicating ongoing germinal centre reactions. Overall, we show that antigen-specific activated and germinal centre B cells as well as plasma cells can be found in the tumour microenvironment. Our findings provide a better understanding of humoral immune responses in human cancer and suggest that tumour-infiltrating B cells could be harnessed for the development of therapeutic agents., (© 2020. The Author(s), under exclusive licence to Springer Nature Limited.)

T cells are important in tumour immunity but a better understanding is needed of the differentiation of antigen-specific T cells in human cancer 1,2 . Here we studied CD8 T cells in patients with human papillomavirus (HPV)-positive head and neck cancer and identified several epitopes derived from HPV E2, E5 and E6 proteins that allowed us to analyse virus-specific CD8 T cells using major histocompatibility complex (MHC) class I tetramers. HPV-specific CD8 T cells expressed PD-1 and were detectable in the tumour at levels that ranged from 0.1% to 10% of tumour-infiltrating CD8 T lymphocytes (TILs) for a given epitope. Single-cell RNA-sequencing analyses of tetramer-sorted HPV-specific PD-1 + CD8 TILs revealed three transcriptionally distinct subsets. One subset expressed TCF7 and other genes associated with PD-1 + stem-like CD8 T cells that are critical for maintaining T cell responses in conditions of antigen persistence. The second subset expressed more effector molecules, representing a transitory cell population, and the third subset was characterized by a terminally differentiated gene signature. T cell receptor clonotypes were shared between the three subsets and pseudotime analysis suggested a hypothetical differentiation trajectory from stem-like to transitory to terminally differentiated cells. More notably, HPV-specific PD-1 + TCF-1 + stem-like TILs proliferated and differentiated into more effector-like cells after in vitro stimulation with the cognate HPV peptide, whereas the more terminally differentiated cells did not proliferate. The presence of functional HPV-specific PD-1 + TCF-1 + CD45RO + stem-like CD8 T cells with proliferative capacity shows that the cellular machinery to respond to PD-1 blockade exists in HPV-positive head and neck cancer, supporting the further investigation of PD-1 targeted therapies in this malignancy. Furthermore, HPV therapeutic vaccination efforts have focused on E6 and E7 proteins; our results suggest that E2 and E5 should also be considered for inclusion as vaccine antigens to elicit tumour-reactive CD8 T cell responses of maximal breadth., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Immune checkpoint inhibitors (ICI) have revolutionized the treatment of metastatic renal cell carcinoma (mRCC). Biomarkers for mRCC patients treated with ICI are limited, and body composition is underutilized in mRCC. We investigated the association between body composition and clinical outcomes in ICI-treated mRCC patients., Methods: We performed a retrospective analysis of 79 ICI-treated mRCC patients at Winship Cancer Institute from 2015-2020. Baseline CT images were collected at mid-L3 and segmented using SliceOMatic v5.0 (TomoVision). Density of skeletal muscle (SM), subcutaneous fat, inter-muscular fat, and visceral fat were measured and converted to indices by dividing by height(m) 2 (SMI, SFI, IFI, and VFI, respectively). Total fat index (TFI) was defined as the sum of SFI, IFI, and VFI. Patients were characterized as high versus low for each variable at gender-specific optimal cuts using overall survival (OS) as the primary outcome. A prognostic risk score was created based on the beta coefficient from the multivariable Cox model after best subset variable selection. Body composition risk score was calculated as IFI + 2*SM mean + SFI and patients were classified as poor (0-1), intermediate (2), or favorable risk (3-4). Kaplan-Meier method and Log-rank test were used to estimate OS and PFS and compare the risk groups. Concordance statistics (C-statistics) were used to measure the discriminatory magnitude of the model., Results: Most patients were male (73%) and most received ICI as first (35%) or second-line (51%) therapy. The body composition poor-risk patients had significantly shorter OS (HR: 6.37, p<0.001), PFS (HR: 4.19, p<0.001), and lower chance of CB (OR: 0.23, p=0.044) compared to favorable risk patients in multivariable analysis. Patients with low TFI had significantly shorter OS (HR: 2.72, p=0.002), PFS (HR: 1.91, p=0.025), and lower chance of CB (OR: 0.25, p=0.008) compared to high TFI patients in multivariable analysis. The C-statistics were higher for body composition risk groups and TFI (all C-statistics ≥ 0.598) compared to IMDC and BMI., Conclusions: Risk stratification using the body composition variables IFI, SM mean, SFI, and TFI may be prognostic and predictive of clinical outcomes in mRCC patients treated with ICI. Larger, prospective studies are warranted to validate this hypothesis-generating data., Competing Interests: BN has served as a member of the advisory board for Exelixis. BC has a consulting/advisory role with Astellas Medivation, Pfizer, and Blue Earth Diagnostics and receives travel accommodations from Bristol-Myers Squibb. MB has acted as a paid consultant for and/or as a member of the advisory boards of Exelixis, Bayer, BMS, Eisai, Pfizer, AstraZeneca, Janssen, Calithera Biosciences, Genomic Health, Nektar, and Sanofi and has received grants to his institution from Xencor, Bayer, Bristol-Myers Squibb, Genentech/Roche, Seattle Genetics, Incyte, Nektar, AstraZeneca, Tricon Pharmaceuticals, Genome & Company, AAA, Peloton Therapeutics, and Pfizer for work performed as outside of the current study. The remaining 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 © 2021 Martini, Olsen, Goyal, Liu, Evans, Magod, Brown, Yantorni, Russler, Caulfield, Goldman, Nazha, Kissick, Harris, Kucuk, Carthon, Master and Bilen.)

Cytomegalovirus (CMV) is one of the most commonly recognized opportunistic pathogens and remains the most influential known parameter in shaping an individual's immune system. As such, T cells induced by CMV infection could have a long-term impact on subsequent immune responses. Accumulating evidence indicates that memory T cells developed during past bacterial and viral infection can cross-react with unrelated pathogens, including transplant antigens, and can alter responses to de novo infections, vaccines, cancers, or rejection. Therefore, careful examination of T cell responses elicited by CMV is warranted to understand their potentially beneficial or harmful roles in future major immune events. Our detailed exploration of the distribution, phenotype, TCR repertoire and transcriptome of CD4+ T cells within CMV seropositive healthy individuals using high-dimensional flow cytometry and single cell multi-omics sequencing reveals that CMV seropositivity has highly significant age-independent effects, leading to a reduction in CD4+ naïve T cells and an expansion of CD4+ effector memory T cells and CD45RA+ effector memory T cells. These induced CD4+ effector memory T cells undergo a specific differentiation trajectory resulting in a subpopulation of CD57+CD27-CD28-CD244+ CD4+ T cells with cytotoxic function and TCR oligoclonality for optimal controlled coexistence with cytomegalovirus. Through gene set enrichment analysis, we found that this subpopulation is similar to virus-specific CD8+ T cells and T cells that mediate acute rejection in patients using tacrolimus and belatacept, a selective costimulation blocker. Together, these data suggest that memory CD4+ T cells induced by cytomegalovirus are formed via a distinct differentiation program to acquire cytotoxic function and can be potentially detrimental to transplant patients adopting costimulation blockade immunosuppressive regimen., 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 © 2021 Zhang, Morris, Peek, Karadkhele, Robertson, Kissick and Larsen.)

Tumor-infiltrating CD8 T cells are associated with improved patient survival and response to immunotherapy in various cancers. Persistent antigen leads to CD8 T-cell exhaustion, where proliferation/self-renewal and killing are divided within distinct subsets of CD8 T cells in the tumor. CD8 T-cell responses in chronic antigen settings must be maintained for long periods of time, suggesting that mechanisms that regulate chronic CD8 T-cell responses may differ from those in acute settings. Currently, factors that regulate the maintenance of stem-like CD8 T cells in the tumor or their differentiation into terminally differentiated cells are unknown. In this review, we discuss the role of dendritic cells in the activation and differentiation of CD8 T-cell subsets within secondary lymphoid tissue and tumors. In addition, we examine changes in CD4 T-cell differentiation in response to chronic antigens and consider how subset-specific mechanisms could assist the stem-like and terminally differentiated CD8 T-cell subsets. Finally, we highlight how tumor-infiltrating CD4 T cells and dendritic cells interact with CD8 T cells within organized lymphoid-like areas in the tumor and propose a CD8 T-cell differentiation model that requires the collaboration of CD4 T cells and dendritic cells. These organized interactions coordinate the anti-tumor response and control disease progression by mechanisms that regulate CD8 T-cell differentiation, which permit the maintenance of an effective balance of stem-like and terminally differentiated CD8 T cells., (© The Japanese Society for Immunology. 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Revealing the mechanisms that underlie the expansion of antitumor CD8 + T cells that are associated with improved clinical outcomes is critical to improving immunotherapeutic management of melanoma. How the lymphatic system, which orchestrates the complex sensing of antigen by lymphocytes to mount an adaptive immune response, facilitates this response in the context of malignancy is incompletely understood. To delineate the effects of lymphatic transport and tumor-induced lymphatic and lymph node (LN) remodeling on the elicitation of CD8 + T cell immunity within LNs, we designed a suite of nanoscale biomaterial tools enabling the quantification of antigen access and presentation within the LN and resulting influence on T cell functions. The expansion of antigen-specific stem-like and cytotoxic CD8 + T cell pools was revealed to be sensitive to the mechanism of lymphatic transport to LNs, demonstrating the potential for nanoengineering strategies targeting LNs to optimize cancer immunotherapy in eliciting antitumor CD8 + T cell immunity., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Systemic administration of immune checkpoint blockade (ICB) monoclonal antibodies (mAbs) can unleash antitumor functions of T cells but is associated with variable response rates and off-target toxicities. We hypothesized that antitumor efficacy of ICB is limited by the minimal accumulation of mAb within tissues where antitumor immunity is elicited and regulated, which include the tumor microenvironment (TME) and secondary lymphoid tissues. In contrast to systemic administration, intratumoral and intradermal routes of administration resulted in higher mAb accumulation within both the TME and its draining lymph nodes (LNs) or LNs alone, respectively. The use of either locoregional administration route resulted in pronounced T cell responses from the ICB therapy, which developed in the secondary lymphoid tissues and TME of treated mice. Targeted delivery of mAb to tumor-draining lymph nodes (TdLNs) alone was associated with enhanced antitumor immunity and improved therapeutic effects compared to conventional systemic ICB therapy, and these effects were sustained at reduced mAb doses and comparable to those achieved by intratumoral administration. These data suggest that locoregional routes of administration of ICB mAb can augment ICB therapy by improving immunomodulation within TdLNs., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Recent studies on chronic viral infections have defined a novel programmed cell death 1-positive (PD-1 + ) T cell factor 1-positive (TCF1 + ) stem-like CD8 T cell subset that gives rise to the terminally differentiated exhausted CD8 T cells. In this study, we performed T cell receptor beta (TCRβ) sequencing of virus-specific CD8 T cells during chronic lymphocytic choriomeningitis virus (LCMV) infection to examine the TCR diversity and lineage relationship of these two functionally distinct subsets. We found that >95% of the TCR repertoire of the exhausted CD8 T cell subset was shared with the stem-like CD8 T cells. The TCR repertoires of both CD8 T cell subsets were composed mostly of a few dominant clonotypes, but there was slightly more breadth and diversity in the stem-like CD8 T cells than their exhausted counterpart (∼40 versus ∼15 GP33 + clonotypes; ∼20 versus ∼7 GP276 + clonotypes). Interestingly, the breadth of the TCR repertoire was broader during the early stages (day 8) of the chronic infection than the later stages (days 45 to 60), showing that there was a narrowing of the TCR repertoire during chronic infection (∼2-fold GP33 + and GP276 + stem-like subset; ∼10-fold GP33 + and ∼5-fold GP276 + exhausted subset). In contrast, during acute LCMV infection, the TCR repertoire was much broader in both GP33-specific effector (∼160 clonotypes) and memory CD8 T cells (∼160 clonotypes). Overall, our data demonstrate that the virus-specific CD8 T cell TCR repertoire is broad and remains stable after acute LCMV infection, but it contracts and is narrower during chronic infection. Our study also shows that the repertoire of the exhausted CD8 T cell subset is almost completely derived from the stem-like CD8 T cell subset during established chronic LCMV infection. IMPORTANCE CD8 TCR repertoires responding to chronic viral infections (HIV, hepatitis C virus [HCV], Epstein-Barr virus [EBV], and cytomegalovirus [CMV]) have limited breadth and diversity. How these repertoires change and are maintained throughout the chronic infection are unknown. We thus characterized the LCMV-specific CD8 TCR repertoires of stem-like and terminally exhausted subsets generated during chronic LCMV infections. During chronic LCMV infections, the repertoires started as diverse but became more clonal at the late time point. Further, the exhausted subset was composed of dominant clonotypes that were shared with the stem-like subset. Together, we demonstrate that the TCR repertoire contracts over time and is almost exclusively derived from the stem-like subset late during the persistent viral infection. Our data suggest that dominant clonotypes in the exhausted subset are derived from a diverse pool of stem-like clonotypes, which may be contributing to the clonality observed during chronic viral infections., (Copyright © 2020 American Society for Microbiology.)

Background: The International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) criteria are the gold standard for risk-stratifying patients with metastatic renal cell cancer (mRCC). We developed a novel risk scoring system for patients with mRCC treated with immune checkpoint inhibitors (ICIs)., Methods: We performed a retrospective analysis of 100 ICI-treated patients with mRCC at Winship Cancer Institute from 2015 to 2018. Several baseline variables were collected, including markers of inflammation, body mass index (BMI), and sites of metastatic disease, and all were considered for inclusion in our risk scoring system. Upon variable selection in multivariable model, monocyte-to-lymphocyte ratio (MLR), BMI, and number and sites of metastases at baseline were used for risk score calculation. Patients were categorized using four-level risk groups as good (risk score = 0), intermediate (risk score = 1), poor (risk score = 2), or very poor (risk score = 3-4). Cox's proportional hazard model and the Kaplan-Meier method were implemented for survival outcomes., Results: Most patients were male (66%) with clear cell renal cell carcinoma (72%). The majority (71%) received anti-programmed cell death protein-1 monotherapy. Our risk scoring criteria had higher Uno's concordance statistics than IMDC in predicting overall survival (OS; 0.71 vs. 0.57) and progression-free survival (0.61 vs. 0.58). Setting good risk (MLR <0.93, BMI ≥24, and D&#95;Met = 0) as the reference, the OS hazard ratios were 29.5 (95% confidence interval [CI], 3.64-238.9), 6.58 (95% CI, 0.84-51.68), and 3.75 (95% CI, 0.49-28.57) for very poor, poor, and intermediate risk groups, respectively., Conclusion: Risk scoring using MLR, BMI, and number and sites of metastases may be an effective way to predict survival in patients with mRCC receiving ICI. These results should be validated in a larger, prospective study., Implications for Practice: A risk scoring system was created for patients with metastatic renal cell carcinoma treated with immune checkpoint inhibitors. The results of this study have significant implications for practicing oncologists in the community and academic setting. Importantly, these results identify readily available risk factors that can be used clinically to risk-stratify patients with metastatic renal cell carcinoma who are treated with immune checkpoint inhibitors., (© 2019 The Authors. The Oncologist published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

Background: Sarcopenia and inflammation have been associated with poor survival in patients with cancer. We explored the combined effects of these variables on survival in patients with cancer treated with immunotherapy., Methods: We performed a retrospective review of 90 patients enrolled on immunotherapy-based phase I clinical trials at Emory University from 2009 to 2017. Baseline neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and platelet-to-lymphocyte ratio (PLR) were used as surrogates of inflammation. The skeletal muscle index (SMI) was derived from the skeletal muscle density calculated from baseline abdominal computed tomography images. Optimal cutoffs for continuous inflammation biomarkers and SMI were determined by bias-adjusted log-rank test. A four-level risk stratification was used to create low-risk (PLR <242 and nonsarcopenic), intermediate-risk (PLR <242 and sarcopenic), high-risk (PLR ≥242 and nonsarcopenic), and very-high-risk (PLR ≥242 and sarcopenic) groups with subsequent association with survival., Results: Most patients (59%) were male, and the most common cancers were melanoma (33%) and gastrointestinal (22%). Very high-risk, high-risk, and intermediate-risk patients had significantly shorter overall survival (hazard ratio [HR], 8.46; 95% confidence interval [CI], 2.65-27.01; p < .001; HR, 5.32; CI, 1.96-14.43; p = .001; and HR, 4.01; CI, 1.66-9.68; p = .002, respectively) and progression-free survival (HR, 12.29; CI, 5.15-29.32; p < .001; HR, 3.51; CI, 1.37-9.02; p = .009; and HR, 2.14; CI, 1.12-4.10; p = .022, respectively) compared with low-risk patients., Conclusion: Baseline sarcopenia and elevated inflammatory biomarkers may have a combined effect on decreasing survival in immunotherapy-treated patients in phase I trials. These data may be immediately applicable for medical oncologists for the risk stratification of patients beginning immunotherapeutic agents., Implications for Practice: Sarcopenia and inflammation have been associated with poor survival in patients with cancer, but it is unclear how to apply this information to patient care. The authors created a risk-stratification system that combined sarcopenia and platelet-to-lymphocyte ratio as a marker of systemic inflammation. The presence of sarcopenia and systemic inflammation decreased progression-free survival and overall survival in our cohort of 90 patients who received immunotherapy in phase I clinical trials. The data presented in this study may be immediately applicable for medical oncologists as a way to risk-stratify patients who are beginning treatment with immunotherapy., (© 2019 The Authors. The Oncologist published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

The identity of CD45 isoforms on the T cell surface changes following the activation of naive T cells and impacts intracellular signaling. In this study, we find that the anti-viral memory CD8 + T pool is unexpectedly comprised of both CD45RB hi and CD45RB lo populations. Relative to CD45RB lo memory T cells, CD45RB hi memory T cells have lower affinity and display greater clonal diversity, as well as a persistent CD27 hi phenotype. The CD45RB hi memory population displays a homeostatic survival advantage in vivo relative to CD45RB lo memory, and long-lived high-affinity cells that persisted long term convert from CD45RB lo to CD45RB hi . Human CD45RO + memory is comprised of both CD45RB hi and CD45RB lo populations with distinct phenotypes, and antigen-specific memory to two viruses is predominantly CD45RB hi . These data demonstrate that CD45RB status is distinct from the conventional central/effector T cell memory classification and has potential utility for monitoring and characterizing pathogen-specific CD8 + T cell responses., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Body mass index (BMI) is used to define obesity, but it is an imperfect measure of body composition. In the current study, the authors explored the association between types of fat and survival in patients treated with immunotherapy., Methods: A retrospective analysis of 90 patients who were treated with immunotherapy on phase 1 clinical trials at the Winship Cancer Institute in Atlanta, Georgia, from 2009 through 2017 was performed. Overall survival (OS) and progression-free survival (PFS) were used to measure clinical outcomes. Baseline BMI and radiographic images at the middle of the third lumbar vertebrae were obtained. Fat densities were calculated and converted to indices (subcutaneous fat index [SFI], intermuscular fat index [IFI], and visceral fat index [VFI]) after dividing by height in meters squared. Risk groups were created using recursive partitioning and the regression trees method for SFI and IFI, which were selected by stepwise variable selection among all fat-related variables. The Cox proportional hazards model and Kaplan-Meier method were used for the association with OS and PFS., Results: The majority of patients (59%) were male and diagnosed with melanoma (33%) or gastrointestinal cancers (22%). The median BMI was 27.4 kg/m 2 , the median SFI was 62.78, the median IFI was 4.06, and the median VFI was 40.53. Low-risk patients (those with an SFI ≥73) had a significantly longer OS (hazard ratio, 0.20; 95% CI, 0.09-0.46 [P < .001]) and PFS (hazard ratio, 0.38; 95% CI, 0.20-0.72 [P = .003]) compared with patients at intermediate risk (those with an SFI <73 and IFI <3.4) and poor risk (those with an SFI <73 and IFI ≥3.4). The Uno concordance statistics were found to be higher for fat risk groups than BMI in predicting OS (0.603 vs 0.574; P = .581) and PFS (0.602 vs 0.586; P = .71)., Conclusions: Increased BMI, increased SFI, and decreased IFI may be associated with prolonged survival in patients with cancer who are treated with immunotherapy. Further studies are needed to elucidate the effect of adiposity on the host immune response to immunotherapy., (© 2019 American Cancer Society.)

T cell dysfunction is a characteristic feature of chronic viral infection and cancer. Recent studies in chronic lymphocytic choriomeningitis virus (LCMV) infection have defined a PD-1 + Tcf-1 + CD8 + T cell subset capable of self-renewal and differentiation into more terminally differentiated cells that downregulate Tcf-1 and express additional inhibitory molecules such as Tim3. Here, we demonstrated that expression of the glycoprotein CD101 divides this terminally differentiated population into two subsets. Stem-like Tcf-1 + CD8 + T cells initially differentiated into a transitory population of CD101 - Tim3 + cells that later converted into CD101 + Tim3 + cells. Recently generated CD101 - Tim3 + cells proliferated in vivo, contributed to viral control, and were marked by an effector-like transcriptional signature including expression of the chemokine receptor CX3CR1, pro-inflammatory cytokines, and granzyme B. PD-1 pathway blockade increased the numbers of CD101 - Tim3 + CD8 + T cells, suggesting that these newly generated transitional cells play a critical role in PD-1-based immunotherapy., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background Given the increasing number of available immunotherapeutic agents, more patients are presenting after failing immunotherapy in need of new treatment options. In this study, we investigated the clinical outcomes of patients treated with sequential immunotherapy. Methods We performed a retrospective review of 90 advanced stage cancer patients treated on immunotherapy-based phase 1 clinical trials at Winship Cancer Institute from 2009 to 2017. We included 49 patients with an immune checkpoint inhibitor (ICI)-indicated histology. Patients were analyzed based on whether they had received prior ICI. Clinical outcomes were overall survival (OS), progression-free survival (PFS), and clinical benefit (best response of complete response, partial response, or stable disease). Univariate analysis (UVA) and multivariate analysis (MVA) were performed using Cox proportional hazard or logistic regression model. Covariates included age, liver metastases, number of prior lines of therapy, histology, and Royal Marsden Hospital (RMH) risk group. Results The most common histologies were melanoma (61%) and lung/head and neck cancers (37%). More than half of patients (n = 27, 55%) received at least one ICI prior to trial enrollment: ten received anti-PD-1, two received anti-CTLA-4, five received anti-PD-1/CTLA-4 combination, and ten received multiple ICI. In MVA, ICI-naïve patients had significantly longer OS (HR: 0.22, CI: 0.07-0.70, p = 0.010) and trended towards higher chance of CB (HR: 2.52, CI: 0.49-12.97, p = 0.268). Patients who received prior ICI had substantially shorter median OS (10.9 vs 24.3 months, p = 0.046) and PFS (2.8 vs. 5.1 months, p = 0.380) than ICI-naïve patients per Kaplan-Meier estimation. Within the ICI-naïve group, 78% (7 of 9) of patients who received prior interleukin (IL-2) or interferon gamma (IFNγ) experienced disease control for at least 6 months, compared to a disease control rate of 15% (2 of 13) in patients who had received chemotherapy, targeted therapy, or no prior treatment. Conclusions ICI-naïve patients may experience improved clinical outcomes on immunotherapy-based phase 1 clinical trials than patients who have received prior ICI. This may be particularly true for patients who received prior IL-2 or IFNγ. Further development of immunotherapy combination therapies is needed to improve clinical outcomes of these patients. These results should be validated in a larger study.

Molecular events activating the PI3K pathway are frequently detected in human tumors and the activation of PI3K signaling alters numerous cellular processes including tumor cell proliferation, survival, and motility. More recent studies have highlighted the impact of PI3K signaling on the cellular response to interferons and other immunologic processes relevant to antitumor immunity. Given the ability of IFNγ to regulate antigen processing and presentation and the pivotal role of MHC class I (MHCI) and II (MHCII) expression in T-cell-mediated antitumor immunity, we sought to determine the impact of PI3K signaling on MHCI and MHCII induction by IFNγ. We found that the induction of cell surface MHCI and MHCII molecules by IFNγ is enhanced by the clinical grade PI3K inhibitors dactolisib and pictilisib. We also found that PI3K inhibition increases STAT1 protein levels following IFNγ treatment and increases accessibility at genomic STAT1-binding motifs. Conversely, we found that pharmacologic activation of PI3K signaling can repress the induction of MHCI and MHCII molecules by IFNγ, and likewise, the loss of PTEN attenuates the induction of MHCI, MHCII, and STAT1 by IFNγ. Consistent with these in vitro studies, we found that within human head and neck squamous cell carcinomas, intratumoral regions with high phospho-AKT IHC staining had reduced MHCI IHC staining. IMPLICATIONS: Collectively, these findings demonstrate that MHC expression can be modulated by PI3K signaling and suggest that activation of PI3K signaling may promote immune escape via effects on antigen presentation., (©2019 American Association for Cancer Research.)

Immunotherapy-particularly immune checkpoint blockade-has seen great success in many tumor types. However, checkpoint-based therapies have not demonstrated high levels of success in prostate cancer, and there is much to be learned from both the successes and failures of these treatments. Here we review the evidence that composition of infiltrating immune cells in the tumor microenvironment is fundamental to the response to immunotherapy. Additionally, we discuss the emerging idea that the organization of these immune cells may also be crucial to this response. In prostate cancer, the composition and organization of the tumor immune microenvironment are preeminent topics of discussion and areas of important future investigation., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In response to viral infection, CD8 + T cells undergo expansion and differentiate into distinct classes of effector cells. After clearance of the virus, a small population of long-lived memory cells persists. Comprehensive studies have defined the protein-coding transcriptional changes associated with this process. Here we expand on this prior work by performing RNA-sequencing to identify changes in long noncoding RNA (lncRNA) expression in human and mouse CD8 + T cells responding to viral infection. We identify hundreds of unannotated lncRNAs and show that expression profiles of both known and novel lncRNAs are sufficient to define naive, effector, and memory CD8 + T cell subsets, implying that they may be involved in fate decisions during antigen-driven differentiation. Additionally, in comparing mouse and human lncRNA expression, we find that lncRNAs with conserved sequence undergo similar changes in expression in the two species, suggesting an evolutionarily conserved role for lncRNAs during CD8 + T cell differentiation.

Prostate cancer is one of the most common cancers in men and a leading cause of cancer-related death. Recent advances in the treatment of advanced prostate cancer, including the use of more potent and selective inhibitors of the androgen signaling pathway, have provided significant clinical benefit for men with metastatic castration-resistant prostate cancer (mCRPC). However, most patients develop progressive lethal disease, highlighting the need for more effective treatments. One such approach is immunotherapy, which harness the power of the patient's immune system to identify and destroy cancer cells through the activation of cytotoxic CD8 T cells specific for tumor antigens. Although immunotherapy, particularly checkpoint blockade, can induce significant clinical responses in patients with solid tumors or hematological malignancies, minimal efficacy has been observed in men with mCRPC. In the current review, we discuss our current understanding of the immunological complexity of the immunosuppressive prostate cancer microenvironment, preclinical models of prostate cancer, and recent advances in immunotherapy clinical trials to improve outcomes for men with mCRPC.

Background: Optimal prognostic and predictive biomarkers for patients with advanced-stage cancer patients who received immunotherapy (IO) are lacking. Inflammatory markers, such as the neutrophil-to-lymphocyte ratio (NLR), the monocyte-to-lymphocyte ratio (MLR), and the platelet-to-lymphocyte ratio (PLR), are readily available. The authors investigated the association between these markers and clinical outcomes of patients with advanced-stage cancer who received IO., Methods: A retrospective review was conducted of 90 patients with advanced cancer who received treatment on phase 1 clinical trials of IO-based treatment regimens. NLR, MLR, and PLR values were log-transformed and treated as continuous variables for each patient. Overall survival (OS), progression-free survival (PFS), and clinical benefit were used to measure clinical outcomes. For univariate associations and multivariable analyses, Cox proportional-hazards models or logistic regression models were used., Results: The median patient age was 63 years, and most were men (59%). The most common histologies were melanoma (33%) and gastrointestinal cancers (22%). High baseline NLR, MLR, and PLR values were associated significantly with worse OS and PFS (P < .05) and a lower chance of benefit (NLR and PLR; P < .05). Increased NLR, MLR, and PLR values 6 weeks after baseline were associated with shorter OS and PFS (P ≤ .052)., Conclusions: Baseline and early changes in NLR, MLR, and PLR values were strongly associated with clinical outcomes in patients who received IO-based treatment regimens on phase 1 trials. Confirmation in a homogenous patient population treated on late-stage trials or outside of trial settings is warranted. These values may warrant consideration for inclusion when risk stratifying patients enrolled onto phase 1 clinical trials of IO agents., (© 2018 American Cancer Society.)

Recent work by several groups has undoubtedly shown that we can produce cancer vaccines targeting neoantigens. However, each vaccine is essentially a single-use, patient-specific product, making this approach resource-intensive. For this reason, it is important to ask whether this approach will be any more successful than what has been attempted during the last 30 years using vaccines targeting self-epitopes. Here, we discuss what might be expected from neoantigen vaccines based on our experience in chronic viral infections, and how this new approach may be applied to cancer immunotherapy., (Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.)

Background: Biomarkers to guide treatment in metastatic renal-cell carcinoma (mRCC) are lacking. We aimed to investigate the association between pretreatment neutrophil-to-lymphocyte ratio (NLR) and outcome of patients with mRCC receiving nivolumab., Patients and Methods: Through retrospective chart review, we identified 38 patients with mRCC treated with standard-of-care nivolumab between 2015 and 2016 at Winship Cancer Institute of Emory University. NLR was determined from complete blood count collected before starting treatment, and imaging was performed to assess progression. The NLR cutoff value of 5.5 was determined by log-rank test, and the univariate association with overall survival (OS) or progression-free survival (PFS) was assessed by the Cox proportional hazard model and Kaplan-Meier method., Results: The 38 patients had a median age of 69 years. The PFS and OS for all patients at 12 months was 54% and 69%, respectively. The median PFS was 2.6 months in the high NLR group but not reached in the low NLR group. Low NLR was strongly associated with increased PFS with hazard ratio of 0.20 (95% confidence interval, 0.07-0.64; P = .006). The median OS was 2.7 months in the high NLR group but not reached in the low NLR group. Low NLR was significantly associated with a prolonged OS with hazard ratio of 0.06 (95% confidence interval, 0.01-0.55; P = .012)., Conclusion: Pretreatment NLR < 5.5 is associated with superior PFS and OS. NLR is a biomarker that can inform prognosis for patients with mRCC and should be further validated in larger cohorts and in prospective studies., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Extracellular vesicles (EVs) from bone marrow (BM)-derived mesenchymal stromal cells (BM-MSC) are novel mechanisms of cell-cell communication over short and long distances. BM-MSC have been shown to support human antibody secreting cells (ASC) survival ex vivo , but whether the crosstalk between the MSC-ASC interaction can occur via EVs is not known. Thus, we evaluated the role of EVs in ASC survival and IgG secretion. EVs were isolated from irradiated and non-irradiated primary BM-MSC and were quantified. They were further characterized by electron microscopy (EM) and CD63 and CD81 immuno-gold EM staining. Human ASC were isolated via fluorescence-activated cell sorting (FACS) and cultured ex vivo with the EV fractions, the EV-reduced fractions, or conventional media. IgG Elispots were used to measure the survival and functionality of the ASC. Contents of the EV fractions were evaluated by proteomics. We saw that both irradiated and non-irradiated MSC secretome preparations afforded vesicles of a size consistent with EVs. Both preparations appeared comparable in EM morphology and CD63 and CD81 immuno-gold EM. Both irradiated and non-irradiated EV fractions supported ASC function, at 88% and 90%, respectively, by day 3. In contrast, conventional media maintained only 4% ASC survival by day 3. To identify the specific factors that provided in vitro ASC support, we compared proteomes of the irradiated and non-irradiated EV fractions with conventional media. Pathway analysis of these proteins identified factors involved in the vesicle-mediated delivery of integrin signalling proteins. These findings indicate that BM-MSC EVs provide an effective support system for ASC survival and IgG secretion.

Antigen-specific CD8 T cells are central to the control of chronic infections and cancer, but persistent antigen stimulation results in T cell exhaustion. Exhausted CD8 T cells have decreased effector function and proliferative capacity, partly caused by overexpression of inhibitory receptors such as programmed cell death (PD)-1. Blockade of the PD-1 pathway has opened a new therapeutic avenue for reinvigorating T cell responses, with positive outcomes especially for patients with cancer. Other strategies to restore function in exhausted CD8 T cells are currently under evaluation-many in combination with PD-1-targeted therapy. Exhausted CD8 T cells comprise heterogeneous cell populations with unique differentiation and functional states. A subset of stem cell-like PD-1 + CD8 T cells responsible for the proliferative burst after PD-1 therapy has been recently described. A greater understanding of T cell exhaustion is imperative to establish rational immunotherapeutic interventions.

Programmed cell death protein 1 (PD-1) immune checkpoint inhibitors have shown activity in patients with advanced renal cell carcinoma (RCC). However, the role of PD-1 expression in tumor-infiltrating lymphocytes (TILs) as a biomarker for poor outcome is not clear. In this study, we evaluated the prognostic value of TIL PD-1 expression in patients with clear cell RCC (ccRCC). 82 patients who underwent nephrectomy for localized or metastatic ccRCC and followed up for at least four years were searched from our database and retrospectively enrolled. Their fixed primary tumor specimens were stained with anti-PD-1 (NAT105). The specimens were classified as negative or positive for PD-1 expression, and the positive specimens were further scored in 10% increments. 37 (45.12%) patients were negative (<1% stained), 26 (31.71%) patients were low (<10 and 10%), and 19 (23.17%) patients were high (20-50%) for PD-1 expression. The prognostic value of TIL PD-1 expression was evaluated by univariate Cox proportional hazards regression on overall and recurrence-free survivals. Higher TIL PD-1 expression was not associated with increased risk of death (P = 0.336) or with increased risk of recurrence (P = 0.572). Higher primary tumor stage was associated with increased risk of recurrence (P = 0.003), and higher Fuhrman nuclear grade was associated with increased risk of death (P <0.001) and with increased risk of recurrence (P <0.001). Our study shows that TIL PD-1 expression by immunohistochemistry (IHC) does not correlate with poor clinical outcome in patients with ccRCC and is inferior to established prognosticating tools.

Two pharmacologic approaches that are currently at the forefront of treating advanced cancer are those that center on disrupting critical growth/survival signaling pathways within tumor cells (commonly referred to as "targeted therapies") and those that center on enhancing the capacity of a patient's immune system to mount an antitumor response (immunotherapy). Maximizing responses to both of these approaches requires an understanding of the oncogenic events present in a given patient's tumor and the nature of the tumor-immune microenvironment. Although these 2 modalities were developed and initially used independently, combination regimens are now being tested in clinical trials, underscoring the need to understand how targeted therapies influence immunologic events. Translational studies and preclinical models have demonstrated that targeted therapies can influence immune cell trafficking, the production of and response to chemokines and cytokines, antigen presentation, and other processes relevant to antitumor immunity and immune homeostasis. Moreover, because these and other effects of targeted therapies occur in nonmalignant cells, targeted therapies are being evaluated for use in applications outside of oncology., (© 2017, The American College of Clinical Pharmacology.)

The differentiation of human memory CD8 T cells is not well understood. Here we address this issue using the live yellow fever virus (YFV) vaccine, which induces long-term immunity in humans. We used in vivo deuterium labelling to mark CD8 T cells that proliferated in response to the virus and then assessed cellular turnover and longevity by quantifying deuterium dilution kinetics in YFV-specific CD8 T cells using mass spectrometry. This longitudinal analysis showed that the memory pool originates from CD8 T cells that divided extensively during the first two weeks after infection and is maintained by quiescent cells that divide less than once every year (doubling time of over 450 days). Although these long-lived YFV-specific memory CD8 T cells did not express effector molecules, their epigenetic landscape resembled that of effector CD8 T cells. This open chromatin profile at effector genes was maintained in memory CD8 T cells isolated even a decade after vaccination, indicating that these cells retain an epigenetic fingerprint of their effector history and remain poised to respond rapidly upon re-exposure to the pathogen.

Memory CD8 T cells that circulate in the blood and are present in lymphoid organs are an essential component of long-lived T cell immunity. These memory CD8 T cells remain poised to rapidly elaborate effector functions upon re-exposure to pathogens, but also have many properties in common with naive cells, including pluripotency and the ability to migrate to the lymph nodes and spleen. Thus, memory cells embody features of both naive and effector cells, fuelling a long-standing debate centred on whether memory T cells develop from effector cells or directly from naive cells. Here we show that long-lived memory CD8 T cells are derived from a subset of effector T cells through a process of dedifferentiation. To assess the developmental origin of memory CD8 T cells, we investigated changes in DNA methylation programming at naive and effector cell-associated genes in virus-specific CD8 T cells during acute lymphocytic choriomeningitis virus infection in mice. Methylation profiling of terminal effector versus memory-precursor CD8 T cell subsets showed that, rather than retaining a naive epigenetic state, the subset of cells that gives rise to memory cells acquired de novo DNA methylation programs at naive-associated genes and became demethylated at the loci of classically defined effector molecules. Conditional deletion of the de novo methyltransferase Dnmt3a at an early stage of effector differentiation resulted in reduced methylation and faster re-expression of naive-associated genes, thereby accelerating the development of memory cells. Longitudinal phenotypic and epigenetic characterization of the memory-precursor effector subset of virus-specific CD8 T cells transferred into antigen-free mice revealed that differentiation to memory cells was coupled to erasure of de novo methylation programs and re-expression of naive-associated genes. Thus, epigenetic repression of naive-associated genes in effector CD8 T cells can be reversed in cells that develop into long-lived memory CD8 T cells while key effector genes remain demethylated, demonstrating that memory T cells arise from a subset of fate-permissive effector T cells.

Translation is a critical process in protein synthesis, but translational regulation in antigen-specific T cells in vivo has not been well defined. Here we have characterized the translatome of virus-specific CD8 + effector T cells (T eff cells) during acute infection of mice with lymphocytic choriomeningitis virus (LCMV). Antigen-specific T cells exerted dynamic translational control of gene expression that correlated with cell proliferation and stimulation via the T cell antigen receptor (TCR). The translation of mRNAs that encode translation machinery, including ribosomal proteins, was upregulated during the T cell clonal-expansion phase, followed by inhibition of the translation of those transcripts when the CD8 + T eff cells stopped dividing just before the contraction phase. That translational suppression was more pronounced in terminal effector cells than in memory precursor cells and was regulated by antigenic stimulation and signals from the kinase mTOR. Our studies show that translation of transcripts encoding ribosomal proteins is regulated during the differentiation of CD8 + T eff cells and might have a role in fate 'decisions' involved in the formation of memory cells.