Search

CD8+ T cells are essential for adaptive immunity against infection and tumors. Their ability to proliferate after stimulation is crucial to their functionality. Dendritic cells (DCs) are professional antigen‐presenting cells that induce their proliferation. Here, we show that thapsigargin‐induced LAD2 mast cell (MC) line‐released products can impair the ability of monocyte‐derived DCs to induce CD8+ T‐cell proliferation and the generation of Th1 cytokine‐producing T cells. We found that culture medium conditioned with LAD2 MCs previously stimulated with thapsigargin (thapsLAD2) induces maturation of DCs as determined by the maturation markers CD80, CD83, CD86, and HLA‐DR. However, thapsLAD2‐matured DCs produced no detectable TNFα or IL‐12 during the maturation. In addition, although their surface expression of PD‐L1 was comparable with the immature or TLR7/8‐agonist (R848)‐matured DCs, their TIM‐3 expression was significantly higher than in immature DCs and even much higher than in R848‐matured DCs. In addition, contrary to R848‐matured DCs, the thapsLAD2‐matured DCs only tended to induce enhanced proliferation of CD4+ T cells than immature DCs. For CD8+ T cells, this tendency was not even detected because thapsLAD2‐matured and immature DCs comparably induced their proliferation, which contrasted with the significantly enhanced proliferation induced by R848‐matured DCs. Furthermore, these differences were comparably recapitulated in the ability of the tested DCs to induce IFNγ‐ and IFNγ/TNFα‐producing T cells. These findings show a novel mechanism of MC‐mediated regulation of adaptive immune responses. [ABSTRACT FROM AUTHOR]

Ex vivo-produced dendritic cells (DCs) constitute the core of active cellular immunotherapy (ACI) for cancer treatment. After many disappointments in clinical trials, the current protocols for their preparation are attempting to boost their therapeutic efficacy by enhancing their functionality towards Th1 response and capability to induce the expansion of cytotoxic tumor-specific CD8+ T cells. LL-37 is an antimicrobial peptide with strong immunomodulatory potential. This potential was previously found to either enhance or suppress the desired anti-tumor DC functionality when used at different phases of their ex vivo production. In this work, we show that LL-37 can be implemented during the whole process of DC production in a way that allows LL-37 to enhance the anti-tumor functionality of produced DCs. We found that the supplementation of LL-37 during the differentiation of monocyte-derived DCs showed only a tendency to enhance their in vitro-induced lymphocyte enrichment with CD8+ T cells. The supplementation of LL-37 also during the process of DC antigen loading (pulsation) and maturation significantly enhanced the cell culture enrichment with CD8+ T cells. Moreover, this enrichment was also associated with the downregulated expression of PD-1 in CD8+ T cells, significantly higher frequency of tumor cell-reactive CD8+ T cells, and superior in vitro cytotoxicity against tumor cells. These data showed that LL-37 implementation into the whole process of the ex vivo production of DCs could significantly boost their anti-tumor performance in ACI. [ABSTRACT FROM AUTHOR]

Simple Summary: MiR-155 appears to be a significant regulator of immune responses against tumors. The aim of this review is to provide an overview of miR-155 function in distinct immune cell populations and describe how the miR-155-mediated regulation can impact the process of cancer immunoediting. Since miR-155 does not necessarily act only within a single cell, we also touch on the role of miR-155 in cellular communication. Finally, we discuss current developments in the specific targeting of this molecule in the tumor and immune cells and suggest its potential implications in developing novel therapeutic algorithms to increase the efficacy of cancer therapy. MicroRNAs belong to a group of short non-coding RNA molecules that are involved in the regulation of gene expression at multiple levels. Their function was described two decades ago, and, since then, microRNAs have become a rapidly developing field of research. Their participation in the regulation of cellular processes, such as proliferation, apoptosis, cell growth, and migration, made microRNAs attractive for cancer research. Moreover, as a single microRNA can simultaneously target multiple molecules, microRNAs offer a unique advantage in regulating multiple cellular processes in different cell types. Many of these cell types are tumor cells and the cells of the immune system. One of the most studied microRNAs in the context of cancer and the immune system is miR-155. MiR-155 plays a role in modulating innate and adaptive immune mechanisms in distinct immune cell types. As such, miR-155 can be part of the communication between the tumor and immune cells and thus impact the process of tumor immunoediting. Several studies have already revealed its effect on antitumor immune responses, and the targeting of this molecule is increasingly implemented in cancer immunotherapy. In this review, we discuss the current knowledge of miR-155 in the regulation of antitumor immunity and the shaping of the tumor microenvironment, and the plausible implementation of miR-155 targeting in cancer therapy. [ABSTRACT FROM AUTHOR]

The immune checkpoint inhibitors have revolutionized cancer immunotherapy. These inhibitors are game changers in many cancers and for many patients, sometimes show unprecedented therapeutic efficacy. However, their therapeutic efficacy is largely limited in many solid tumors where the tumor-controlled immune microenvironment prevents the immune system from efficiently reaching, recognizing, and eliminating cancer cells. The tumor immune microenvironment is largely orchestrated by immune cells through which tumors gain resistance against the immune system. Among these cells are mast cells and dendritic cells. Both cell types possess enormous capabilities to shape the immune microenvironment. These capabilities stage these cells as cellular checkpoints in the immune microenvironment. Regaining control over these cells in the tumor microenvironment can open new avenues for breaking the resistance of solid tumors to immunotherapy. In this review, we will discuss mast cells and dendritic cells in the context of solid tumors and how these immune cells can, alone or in cooperation, modulate the solid tumor resistance to the immune system. We will also discuss how this modulation could be used in novel immunotherapeutic modalities to weaken the solid tumor resistance to the immune system. This weakening could then help other immunotherapeutic modalities engage against these tumors more efficiently. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (COVID-19) vaccines effectively elicit humoral and cellular immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in healthy populations. This immunity decreases several months after vaccination. However, the efficacy of vaccine-induced immunity and its durability in patients with severe asthma on biological therapy are unknown. In this study, we evaluated the effectiveness and durability of mRNA vaccine-induced SARS-CoV-2-specific humoral and cellular immunity in severe asthma patients on biological therapy. The study included 34 patients with severe asthma treated with anti-IgE (omalizumab, n=17), anti-IL5 (mepolizumab, n=13; reslizumab, n=3), or anti-IL5R (benralizumab, n=1) biological therapy. All patients were vaccinated with two doses of the BNT162b2 mRNA vaccine with a 6-week interval between the doses. We found that this COVID-19 vaccination regimen elicited SARS-CoV-2-specific humoral and cellular immunity, which had significantly declined 6 months after receipt of the second dose of the vaccine. The type of biological treatment did not affect vaccine-elicited immunity. However, patient age negatively impacted the vaccine-induced humoral response. On the other hand, no such age-related impact on vaccine-elicited cellular immunity was observed. Our findings show that treatment of patients with severe asthma with biological therapy does not compromise the effectiveness or durability of COVID-19 vaccine-induced immunity. [ABSTRACT FROM AUTHOR]

The adaptive immune response to severe acute respiratory coronavirus 2 (SARS-CoV-2) is important for vaccine development and in the recovery from coronavirus disease 2019 (COVID-19). Men and cancer patients have been reported to be at higher risks of contracting the virus and developing the more severe forms of COVID-19. Prostate cancer (PCa) may be associated with both of these risks. We show that CD4+ T cells of SARS-CoV-2-unexposed patients with hormone-refractory (HR) metastatic PCa had decreased CD4+ T cell immune responses to antigens from SARS-CoV-2 spike glycoprotein but not from the spiked glycoprotein of the 'common cold'-associated human coronavirus 229E (HCoV-229E) as compared with healthy male volunteers who responded comparably to both HCoV-229E- and SARS-CoV-2-derived antigens. Moreover, the HCoV-229E spike glycoprotein antigen-elicited CD4+ T cell immune responses cross-reacted with the SARS-CoV-2 spiked glycoprotein antigens. PCa patients may have impaired responses to the vaccination, and the cross-reactivity can mediate antibody-dependent enhancement (ADE) of COVID-19. These findings highlight the potential for increased vulnerability of PCa patients to COVID-19. [ABSTRACT FROM AUTHOR]

Objectives: Renal cell carcinoma (RCC) is the most lethal urologic malignancy with increasing incidence worldwide. The conventional treatment strategies for advanced or recurrent RCC are not efficient and show considerable toxicities. Adoptive cell transfer (ACT) has become a promising treatment option for multiple cancers, particularly in combination with other therapeutic approaches. ACT often utilizes extensively in vitro expanded tumor-infiltrating lymphocytes (TILs). However, TILs are a very heterogeneous mix of cell populations and only those populations that have a cytotoxic and migratory potential are thought to deliver a therapeutic impact in ACT. The identification and localization of these therapeutically potent populations are therefore needed.Methods and Materials: A total number of 57 tissue samples from 19 RCC patients who underwent radical nephrectomy was analyzed. The tissue samples were obtained from the tumor, peritumoral tissue, and the adjacent healthy renal tissue. The tissues were sliced, enzymatically dissociated into single cell suspensions and the obtained cells further analyzed by flow cytometry for the expression of markers of lymphocyte cytotoxicity - TRAIL and FasL, and a surrogate marker of lymphocyte migratory activity - PECAM-1. The analyzed data were next correlated with the clinical and histopathological data.Results: Non-clear cell RCC (non-ccRCC) tumors showed a significantly decreased tumor infiltration with TRAIL+FasL+ NK cells but elevated infiltration with FasL+PECAM-1+ T cells as compared with clear cell RCC (ccRCC) tumors. Further analyses revealed that the peritumoral tissue of ccRCC patients is a reservoir of TRAIL+FasL+, TRAIL+PECAM-1+, or FasL+PECAM-1+ NK and T cells.Conclusions: The cytotoxic/migratory lymphocytes were identified in tumors of ccRCC patients. These lymphocytes became excluded from the tumor and accumulated in the patient's peritumoral tissue. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) and mast cells (MCs) are key players of the immune system, often coming in close proximity in peripheral tissues. The interplay of these cells is, however, still poorly understood, especially with regards to human cells. The reason for that is the absence of a well established in vitro human cell-based study system that would allow a simultaneous preparation of both cell types. In this study, we show a method for simultaneous generation of DCs and MCs from CD34 + stem cell progenitors that were isolated from the non-adherent fraction of non-mobilized peripheral blood mononuclear cells of healthy donors. We observed that combining stem cells factor (SCF), IL-3 and GM-CSF in serum-free StemPro-34 medium allowed CD34 + cells isolated from an equivalent of 450 ml of peripheral blood to expand to 10–92 × 10 6 cells after 7 weeks of culturing. These cultures comprised of 6–53% of DCs and 1–21% of MCs as determined by the expression of, respectively, CD11c/HLA-DR or CD117/FcεRI. The DCs were CD1a − CD14 − , did not express co-stimulatory molecules CD80 and CD83 and chemokine receptor CCR7. However, the DCs expressed co-stimulatory molecule CD86, and had a capacity to uptake dextran, phagocyte latex particles and induce alloreactivity. MCs, on the other hand, degranulated after crosslinking of FcεRI-bound IgE as determined by the externalization of CD107b. Collectively, our data show that CD34 + -derived human DCs and MCs can be generated in a single culture using CD34 + cells isolated from non-mobilized human peripheral blood and that this method may allow ex vivo studies on DC-MC interplay in human system. [ABSTRACT FROM AUTHOR]

The preparation of dendritic cells (DCs) for adoptive cellular immunotherapy (ACI) requires the maturation of ex vivo-produced immature(i) DCs. This maturation ensures that the antigen presentation triggers an immune response towards the antigen-expressing cells. Although there is a large number of maturation agents capable of inducing strong DC maturation, there is still only a very limited number of these agents approved for use in the production of DCs for ACI. In seeking novel DC maturation agents, we used differentially activated human mast cell (MC) line LAD2 as a cellular adjuvant to elicit or modulate the maturation of ex vivo-produced monocyte-derived iDCs. We found that co-culture of iDCs with differentially activated LAD2 MCs in serum-containing media significantly modulated polyinosinic:polycytidylic acid (poly I:C)-elicited DC maturation as determined through the surface expression of the maturation markers CD80, CD83, CD86, and human leukocyte antigen(HLA)-DR. Once iDCs were generated in serum-free conditions, they became refractory to the maturation with poly I:C, and the LAD2 MC modulatory potential was minimized. However, the maturation-refractory phenotype of the serum-free generated iDCs was largely overcome by co-culture with thapsigargin-stimulated LAD2 MCs. Our data suggest that differentially stimulated mast cells could be novel and highly potent cellular adjuvants for the maturation of DCs for ACI. [ABSTRACT FROM AUTHOR]

Simple Summary: Expanded, antigen-experienced CD8+ T cells are utilized in immunotherapy to treat infections and cancers. Antigen rechallenge of these cells leads to their re-expansion. The effector functions of re-expanded CD8+ T cells are critical for their therapeutic efficacy. We found that acute conditioning of the cells, before antigen rechallenge, impacts their effector function after re-expansion. Our data showed that acute pharmacological modulation of the GSK3β-mTORC axis with TWS119 or rapamycin, but not Torin1, before antigen rechallenge promotes the effector functions of re-expanded CD8+ T cells. These findings suggest that acute conditioning of the GSK3β-mTORC axis in expanded CD8+ T cells, before antigen rechallenge, can promote the therapeutic performance of re-expanded CD8+ T cells. CD8+ T cells protect against tumors and intracellular pathogens. The inflammatory cytokines IL-2, IL-15, and IL-7 are necessary for their expansion. However, elevated serum levels of these cytokines are often associated with cancer, poorer prognosis of cancer patients, and exhaustion of antigen-expanded CD8+ T cells. The impact of acute conditioning of antigen-expanded CD8+ T cells with these cytokines is unknown. Here, we generated antigen-expanded CD8+ T cells using dendritic cells and PC-3 cells. The cells were acutely (18–24 h) conditioned with IL-2 and either the GSK3β inhibitor TWS119, the mTORC1 inhibitor rapamycin, or the mTORC1/2 inhibitor Torin1, then their immediate and post-re-expansion (distal) cytokine responses after antigen rechallenge were evaluated. We found that acute IL-2 conditioning upregulated the immediate antigen-induced cytokine response of the tested cells. Following their re-expansion, however, the cells showed a decreased cytokine response. These IL-2 conditioning-mediated impacts were counteracted with TWS119 or rapamycin but not with Torin1. Our data revealed that the acute conditioning of antigen-expanded CD8+ T cells with IL-2 modulates the GSK3β-mTORC signaling axis. This modulation differentially affected the immediate and distal cytokine responses of the cells. The acute targeting of this signaling axis could, therefore, represent a novel strategy for the modulation of antigen-expanded CD8+ T cells. [ABSTRACT FROM AUTHOR]

CD8 + T cells are essential for adaptive immunity against infection and tumors. Their ability to proliferate after stimulation is crucial to their functionality. Dendritic cells (DCs) are professional antigen-presenting cells that induce their proliferation. Here, we show that thapsigargin-induced LAD2 mast cell (MC) line-released products can impair the ability of monocyte-derived DCs to induce CD8 + T-cell proliferation and the generation of Th1 cytokine-producing T cells. We found that culture medium conditioned with LAD2 MCs previously stimulated with thapsigargin (thapsLAD2) induces maturation of DCs as determined by the maturation markers CD80, CD83, CD86, and HLA-DR. However, thapsLAD2-matured DCs produced no detectable TNF α or IL-12 during the maturation. In addition, although their surface expression of PD-L1 was comparable with the immature or TLR7/8-agonist (R848)-matured DCs, their TIM-3 expression was significantly higher than in immature DCs and even much higher than in R848-matured DCs. In addition, contrary to R848-matured DCs, the thapsLAD2-matured DCs only tended to induce enhanced proliferation of CD4 + T cells than immature DCs. For CD8 + T cells, this tendency was not even detected because thapsLAD2-matured and immature DCs comparably induced their proliferation, which contrasted with the significantly enhanced proliferation induced by R848-matured DCs. Furthermore, these differences were comparably recapitulated in the ability of the tested DCs to induce IFN γ - and IFN γ /TNF α -producing T cells. These findings show a novel mechanism of MC-mediated regulation of adaptive immune responses., Competing Interests: Jirina Bartunkova is a part-time employee and a minority shareholder of Sotio, a.s., a biotech company that is developing novel immunotherapies. Katerina Kalkusova, Pavla Taborska, Dmitry Stakheev, Michal Rataj, Sindija Smite, Elea Darras, Julia Albo, Luca Vannucci, and Daniel Smrz declare no conflicts of interest., (Copyright © 2024 Katerina Kalkusova et al.)

The adaptive immune response to severe acute respiratory coronavirus 2 (SARS-CoV-2) is important for vaccine development and in the recovery from coronavirus disease 2019 (COVID-19). Men and cancer patients have been reported to be at higher risks of contracting the virus and developing the more severe forms of COVID-19. Prostate cancer (PCa) may be associated with both of these risks. We show that CD4 + T cells of SARS-CoV-2-unexposed patients with hormone-refractory (HR) metastatic PCa had decreased CD4 + T cell immune responses to antigens from SARS-CoV-2 spike glycoprotein but not from the spiked glycoprotein of the 'common cold'-associated human coronavirus 229E (HCoV-229E) as compared with healthy male volunteers who responded comparably to both HCoV-229E- and SARS-CoV-2-derived antigens. Moreover, the HCoV-229E spike glycoprotein antigen-elicited CD4 + T cell immune responses cross-reacted with the SARS-CoV-2 spiked glycoprotein antigens. PCa patients may have impaired responses to the vaccination, and the cross-reactivity can mediate antibody-dependent enhancement (ADE) of COVID-19. These findings highlight the potential for increased vulnerability of PCa patients to COVID-19., Competing Interests: LS is a part-time employee of SOTIO, a.s., a biotech company developing cell-based immunotherapy. JB is a part-time employee and a minority shareholder of SOTIO, a.s. 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 Taborska, Strizova, Stakheev, Sojka, Bartunkova and Smrz.)