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Introduction: The transcription factor HELIOS is primarily known for its expression in CD4 regulatory T cells, both in humans and mice. In mice, HELIOS is found in exhausted CD8 T cells. However, information on human HELIO+ CD8 T cells is limited and conflicting. Methods: In this study, we characterized by flow cytometry and transcriptomic analyses human HELIOS+ CD8 T cells. Results: These T cells primarily consist of memory cells and constitute approximately 21% of blood CD8 T cells. In comparison with memory HELIOST-BEThigh CD8 T cells that displayed robust effector functions, the memory HELIOS+ T-BEThigh CD8 T cells produce lower amounts of IFN-g and TNF-a and have a lower cytotoxic potential. We wondered if these cells participate in the immune response against viral antigens, but did not find HELIOS+ cells among CD8 T cells recognizing CMV peptides presented by HLA-A2 and HLA-B7. However, we found HELIOS+ CD8 T cells that recognize a CMV peptide presented by MHC class Ib molecule HLA-E. Additionally, a portion of HELIOS+ CD8 T cells is characterized by the expression of CD161, often used as a surface marker for identifying TC17 cells. These CD8 T cells express TH17/TC17-related genes encoding RORgt, RORa, PLZF, and CCL20. Discussion: Our findings emphasize that HELIOS is expressed across various CD8 T cell populations, highlighting its significance beyond its role as a transcription factor for Treg or exhausted murine CD8 T cells. The significance of the connection between HELIOS and HLA-E restriction is yet to be understood. [ABSTRACT FROM AUTHOR]

IntroductionThe transcription factor HELIOS is primarily known for its expression in CD4 regulatory T cells, both in humans and mice. In mice, HELIOS is found in exhausted CD8 T cells. However, information on human HELIOS+ CD8 T cells is limited and conflicting. MethodsIn this study, we characterized by flow cytometry and transcriptomic analyses human HELIOS+ CD8 T cells.ResultsThese T cells primarily consist of memory cells and constitute approximately 21% of blood CD8 T cells. In comparison with memory HELIOS- T-BEThigh CD8 T cells that displayed robust effector functions, the memory HELIOS+ T-BEThigh CD8 T cells produce lower amounts of IFN-γ and TNF-α and have a lower cytotoxic potential. We wondered if these cells participate in the immune response against viral antigens, but did not find HELIOS+ cells among CD8 T cells recognizing CMV peptides presented by HLA-A2 and HLA-B7. However, we found HELIOS+ CD8 T cells that recognize a CMV peptide presented by MHC class Ib molecule HLA-E. Additionally, a portion of HELIOS+ CD8 T cells is characterized by the expression of CD161, often used as a surface marker for identifying TC17 cells. These CD8 T cells express TH17/TC17-related genes encoding RORgt, RORa, PLZF, and CCL20. DiscussionOur findings emphasize that HELIOS is expressed across various CD8 T cell populations, highlighting its significance beyond its role as a transcription factor for Treg or exhausted murine CD8 T cells. The significance of the connection between HELIOS and HLA-E restriction is yet to be understood.

Background: C‐C chemokine receptor 5 (CCR5) is a major coreceptor for Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) cell entry; however, its role in brain pathogenesis is largely understudied. Thus, we sought to examine cell type‐specific protein expression of CCR5 during SIV infection of the brain. Methods: We examined occipital cortical tissue from uninfected rhesus macaques and SIV‐infected animals with or without encephalitis using immunohistochemistry and immunofluorescence microscopy to determine the number and distribution of CCR5‐positive cells. Results: An increase in the number of CCR5+ cells in the brain of SIV‐infected animals with encephalitis was accounted for by increased CD3+CD8+ cells expressing CCR5, but not by increased CCR5+ microglia or perivascular macrophages (PVMs), and a concurrent decrease in the percentage of CCR5+ PVMs was observed. Levels of CCR5 and SIV Gag p28 protein expression were examined on a per‐cell basis, and a significant, negative relationship was established indicating decreased CCR5 expression in productively infected cells. While investigating the endocytosis‐mediated CCR5 internalization as a mechanism for CCR5 downregulation, we found that phospho‐ERK1/2, an indicator of clathrin‐mediated endocytosis, was colocalized with infected PVMs and that macrophages from infected animals showed significantly increased expression of clathrin heavy chain 1. Conclusions: These findings show a shift in CCR5‐positive cell types in the brain during SIV pathogenesis with an increase in the number of CCR5+ CD8 T cells, and downregulated CCR5 expression on infected PVMs, likely through ERK1/2‐driven, clathrin‐mediated endocytosis. [ABSTRACT FROM AUTHOR]

Tissue-resident memory CD8 T cells are responsible for local immune surveillance in different tissues, including the brain. They constitute the first line of defense against pathogens and cancer cells and play a role in autoimmunity. A recently published study demonstrated that CD8 T cells with markers of residency containing distinct granzymes and interferon-γ infiltrate the parenchyma of the substantia nigra and contact dopaminergic neurons in an early premotor stage of Parkinson’s disease. This infiltration precedes α-synuclein aggregation and neuronal loss in the substantia nigra, suggesting a relevant role for CD8 T cells in the onset of the disease. To date, the nature of the antigen that initiates the adaptive immune response remains unknown. This review will discuss the role of tissue-resident memory CD8 T cells in brain immune homeostasis and in the onset of Parkinson’s disease and other neurological diseases. We also discuss how aging and genetic factors can affect the CD8 T cell immune response and how animal models can be misleading when studying human-related immune response. Finally, we speculate about a possible infectious or autoimmune origin of Parkinson’s disease.

BACKGROUND: The exact immunopathological mechanisms in the progression of breast cancer are not clearly understood, but various factors including CD8 T lymphocytes have lethal properties on tumor cells. On the other hand, interleukin-37 (IL-37), as a new member of the IL-1 family, is an anti-inflammatory cytokine. The exact role of IL-37 in breast cancer has not yet been determined. OBJECTIVE: This study aimed to evaluate the CD8 T lymphocytes count and IL-37 gene expression in newly diagnosed breast cancer patients with and without metastasis. METHODS: In this study, blood samples from 36 metastatic and 36 non-metastatic breast cancer patients and 36 healthy individuals as control were collected. After RNA extraction and cDNA synthesis, the relative gene expression was performed using real-time PCR. Also, counting the CD8 T lymphocytes was done by flow cytometry technique. RESULTS: The results of this study showed that the gene expression of IL-37 in blood samples of metastatic and non-metastatic breast cancer patients was significantly lower than in healthy individuals (P < 0.05). The relative gene expression of the IL-37 in ER+/PR+/HER2+ patients with non-metastatic breast cancer had a significant increase compared to HER2+ patients (P < 0.05). Also, CD8 T lymphocytes count in the samples of patients including non-metastatic and metastatic breast cancer was significantly decreased compared to the healthy individuals (P < 0.05). CONCLUSIONS: Our findings provide evidence that IL-37 gene expression and CD8 T lymphocytes count, significantly decreased in non-metastatic and metastatic breast cancer. Considering the possible effects of IL-37 on TCD8 cells in tumor immune responses, more research will be done to benefit from the therapeutic effects of this cytokine in the future. [ABSTRACT FROM AUTHOR]

• Previous infection with E. cuniculi reduced CD8 T lymphocytes and macrophages viability. • CD8 T lymphocytes from Xid mice showed low proliferation. • High expression of CD69 and Lamp-1 in CD8 T cells from WT mice uninfected. • A higher microbicidal activity of macrophages co-cultures with CD8 T lymphocytes from Xid mice. Encephalitozoon cuniculi is an opportunistic intracellular pathogen that establishes a balanced relationship with immunocompetent individuals depending on the activity of their CD8+ T cells lymphocytes. However, lower resistance to experimental infection with E. cuniculi was found in B-1 deficient mice (Xid), besides increased the number of CD8 T lymphocytes. Here, we evaluated the profile of CD8+ T lymphocytes from Balb/c wild-type (WT) or Balb/c Xid mice (with B-1 cell deficiency) on the microbicidal activity of macrophages challenged with E. cuniculi. Naïve CD8 T lymphocytes from WT or Xid mice uninfected and primed CD8 T lymphocytes from WT or Xid mice infected with E cuniculi were co-cultured with macrophages previously challenged with E. cuniculi. We evaluated macrophages viability and microbicidal activity, and CD8 T lymphocytes viability and presence of activating molecules (CD62L, CD69, and CD107a). Macrophages co-cultured with naïve CD8 T lymphocytes from WT demonstrated high microbicidal activity. Naïve CD8 T lymphocytes obtained from WT mice had a higher expression of CD69 and LAMP-1-activating molecules compared to Xid CD8+ T lymphocytes. Primed CD8 T lymphocytes from Xid mice proliferated more than those from WT mice, however, when the expression of the activating molecule CD69 associated with the expression of CD62L was kept low. In conclusion, naïve CD8+ T lymphocytes from Xid mice, deficient in B-1 cells, they had reduced expression of activation molecules and cytotoxic activity. [ABSTRACT FROM AUTHOR]

Viral vectors have emerged as a promising alternative to classical vaccines due to their great potential for induction of a potent cellular and humoral immunity. Cytomegalovirus (CMV) is an attractive vaccine vector due to its large genome with many non-essential immunoregulatory genes that can be easily manipulated to modify the immune response. CMV generates a strong antigen-specific CD8 T cell response with a gradual accumulation of these cells in the process called memory inflation. In our previous work, we have constructed a mouse CMV vector expressing NKG2D ligand RAE-1γ in place of its viral inhibitor m152 (RAE-1γMCMV), which proved to be highly attenuated in vivo. Despite attenuation, RAE-1γMCMV induced a substantially stronger CD8 T cell response to vectored antigen than the control vector and provided superior protection against bacterial and tumor challenge. In the present study, we confirmed the enhanced protective capacity of RAE-1γMCMV as a tumor vaccine vector and determined the phenotypical and functional characteristics of memory CD8 T cells induced by the RAE-1γ expressing MCMV. RNAseq data revealed higher transcription of numerous genes associated with effector-like CD8 T cell phenotype in RAE-1γMCMV immunized mice. CD8 T cells primed with RAE-1γMCMV were enriched in TCF1 negative population, with higher expression of KLRG1 and lower expression of CD127, CD27, and Eomes. These phenotypical differences were associated with distinct functional features as cells primed with RAE-1γMCMV showed inferior cytokine-producing abilities but comparable cytotoxic potential. After adoptive transfer into naive hosts, OT-1 cells induced with both RAE-1γMCMV and the control vector were equally efficient in rejecting established tumors, suggesting the context of latent infection and cell numbers as important determinants of enhanced anti-tumor response following RAE-1γMCMV vaccination. Overall, our results shed new light on the phenotypical and functional distinctness of memory CD8 T cells induced with CMV vector expressing cellular ligand for the NKG2D receptor.

Viral vectors have emerged as a promising alternative to classical vaccines due to their great potential for induction of a potent cellular and humoral immunity. Cytomegalovirus (CMV) is an attractive vaccine vector due to its large genome with many non-essential immunoregulatory genes that can be easily manipulated to modify the immune response. CMV generates a strong antigen-specific CD8 T cell response with a gradual accumulation of these cells in the process called memory inflation. In our previous work, we have constructed a mouse CMV vector expressing NKG2D ligand RAE-1γ in place of its viral inhibitor m152 (RAE-1γMCMV), which proved to be highly attenuated in vivo. Despite attenuation, RAE-1γMCMV induced a substantially stronger CD8 T cell response to vectored antigen than the control vector and provided superior protection against bacterial and tumor challenge. In the present study, we confirmed the enhanced protective capacity of RAE-1γMCMV as a tumor vaccine vector and determined the phenotypical and functional characteristics of memory CD8 T cells induced by the RAE-1γ expressing MCMV. RNAseq data revealed higher transcription of numerous genes associated with effector-like CD8 T cell phenotype in RAE-1γMCMV immunized mice. CD8 T cells primed with RAE-1γMCMV were enriched in TCF1 negative population, with higher expression of KLRG1 and lower expression of CD127, CD27, and Eomes. These phenotypical differences were associated with distinct functional features as cells primed with RAE-1γMCMV showed inferior cytokine-producing abilities but comparable cytotoxic potential. After adoptive transfer into naive hosts, OT-1 cells induced with both RAE-1γMCMV and the control vector were equally efficient in rejecting established tumors, suggesting the context of latent infection and cell numbers as important determinants of enhanced anti-tumor response following RAE-1γMCMV vaccination. Overall, our results shed new light on the phenotypical and functional distinctness of memory CD8 T cells induced with CMV vector expressing cellular ligand for the NKG2D receptor. [ABSTRACT FROM AUTHOR]

Introduction: One of the essential mechanisms of virus infection control is cell-mediated cytotoxicity, which can act in an antibody-dependent or -independent fashion and is provided by different effector cells. The role of CD8 T-cells in infection control and in affecting the pathological outcome of different types of infection has been demonstrated in numerous animal studies. Despite this, their role in controlling human influenza infection is not fully understood. Especially, knowledge about their induction and turnover in human influenza infection is limited. Differences in the development of CD8 T-cells after influenza infection or immunizations should be explored in detail, in relation to the bioaccessibility of influenza antigens, site of application and distribution routes. Areas covered: This review focuses on the basics of CD8 T-cell immune response both in human influenza infection and after administration of inactivated or live attenuated influenza vaccine. Some aspects of the accessibility, distribution and presentation of influenza antigens to CD8 T-cells are described. Expert commentary: The CD8 T-cell response is an essential connection between innate and antibody-mediated responses, which are all-important for influenza control. We hypothesize that immunization with live influenza vaccine is the most straightforward artificial way to induce an efficient influenza-specific CD8 T-cell response.

Abstract Adoptive transfer of T cells transduced with Chimeric Antigen Receptors (CAR) are now FDA-approved for the treatment of B-cell malignancies. Yet, the functionality of the endogenous TCR in CART cells has not been fully assessed. Here, we demonstrate that CART cells progressively upregulate Fas, FasL, DR5 and TRAIL, which result in their programmed cell death, independently of antigen-mediated TCR or CAR activation. CART cell apoptosis occurs even when the CAR contains a single (co-)activatory domain such as CD3ζ, CD28 or 4-1BB. Importantly, the dominant role of the Fas and DR5 pathways in CART cell apoptosis is demonstrated by the significant rescue of CART cells upon in vivo blockade by combined Fas-Fc and DR5-Fc recombinant proteins. These observations are of crucial importance for the long-term persistence of CART cells and for the development of new applications including the combined TCR and CAR activation against solid tumors.

Adenocarcinoma of the ampulla of Vater (AOV) is classified into intestinal type (IT) and pancreatobiliary type (PB); however, the immunological properties of these subtypes remain to be characterized. Here, we evaluated the clinical implications of PD-L1 expression and CD8+ T lymphocyte density in adenocarcinomas of the AOV and their potential association with Yes-associated protein (YAP). We analyzed 123 adenocarcinoma-of-the-AOV patients who underwent surgical resection, and tumors were classified into IT or PB type. Tumor or inflammatory cell PD-L1 expression, CD8+ T lymphocyte density in the cancer cell nest (intratumoral) or in the adjacent stroma, and YAP localization and intensity were analyzed using immunohistochemical staining. PB-type tumors showed higher tumoral PD-L1 expression than IT-type tumors, and tumoral PD-L1 expression was associated with a shorter disease-free survival (DFS) [hazard ratio (HR), 1.77; p = 0.045] and overall survival (OS) (HR 1.99; p = 0.030). Intratumoral CD8+ T lymphocyte density was higher in IT type than in PB type and was associated with a favorable DFS (HR 0.47; p = 0.022). The nuclear staining pattern of YAP in tumor cells, compared to non-nuclear staining patterns, was more frequently associated with PB type and increased tumoral PD-L1 expression. Nuclear YAP staining was a significant prognostic factor for OS (HR 2.21; p = 0.022). These results show that the two subtypes of adenocarcinoma of the AOV exhibit significant differences in tumoral PD-L1 expression and intratumoral CD8+ T lymphocyte density, which might contribute to their distinct clinical features. [ABSTRACT FROM AUTHOR]

Introduction: One of the essential mechanisms of virus infection control is cell-mediated cytotoxicity, which can act in an antibody-dependent or -independent fashion and is provided by different effector cells. The role of CD8 T-cells in infection control and in affecting the pathological outcome of different types of infection has been demonstrated in numerous animal studies. Despite this, their role in controlling human influenza infection is not fully understood. Especially, knowledge about their induction and turnover in human influenza infection is limited. Differences in the development of CD8 T-cells after influenza infection or immunizations should be explored in detail, in relation to the bioaccessibility of influenza antigens, site of application and distribution routes. Areas covered: This review focuses on the basics of CD8 T-cell immune response both in human influenza infection and after administration of inactivated or live attenuated influenza vaccine. Some aspects of the accessibility, distribution and presentation of influenza antigens to CD8 T-cells are described. Expert commentary: The CD8 T-cell response is an essential connection between innate and antibody-mediated responses, which are all-important for influenza control. We hypothesize that immunization with live influenza vaccine is the most straightforward artificial way to induce an efficient influenza-specific CD8 T-cell response. [ABSTRACT FROM AUTHOR]

Host immunosuppression occurs during chronic nematode infection, partly due to effector T-cell hyporesponsiveness. The role of P-glycoprotein (P-gp), a member of the ABC transporter family, has been assessed in T-cell activity. This study assesses the possible role of P-gp in T-cell activity during nematode infection. Our findings indicate that blockade of P-gp in vivo increased protection against Heligmosomoides polygyrus nematode infection and was associated with the enhanced T-cell activity. Three P-gp-inhibitors, verapamil ( VRP), cyclosporine (CsA) and tariquidar ( XR9576), were used to determine the influence of nematode infection on the P-gp function of T cells. The influence of the nematode on the uptake, efflux and kinetics of extrusion in T-cell subsets CD4+ and CD8+ was assessed by the accumulation of Rho123 dye. The results indicate that H. polygyrus infection contributes to the inhibition of T-cell function by elevating P-gp activity. The blockade of P-gp in the T cells of infected mice led to an impressive increase in T-cell proliferation and IL-4 cytokine release through the upregulation of NF-κB activation. These results provide the first evidence that the P-gp function of T cells is altered during nematode infection to open the way for further studies aiming to explore the role of P-gp in host-parasite interactions. [ABSTRACT FROM AUTHOR]

For several decades, the leukotriene pathways have been implicated as playing a central role in the pathophysiology of asthma. The presence and elevation of numerous metabolites in the blood, sputum, and bronchoalveolar lavage fluid from asthmatics or experimental animals adds support to this notion. However, targeting of the leukotriene pathways has had, in general, limited success. The single exception in asthma therapy has been targeting of the cysteinyl leukotriene receptor 1, which clinically has proven effective but only in certain clinical situations. Interference with 5-lipoxygenase has had limited success, in part due to adverse drug effects. The importance of the LTB4-BLT1 pathway in asthma pathogenesis has extensive experimental support and findings, albeit limited, from clinical samples. The LTB4-BLT1 pathway was shown to be important as a neutrophil chemoattractant. Despite observations made more than two decades ago, the LTB4-BLT1 pathway has only recently been shown to exhibit important activities on subsets of T lymphocytes, both as a chemoattractant and on lymphocyte activation, as well as on dendritic cells, the major antigen presenting cell in the lung. The role of BLT2 in asthma remains unclear. Targeting of components of the LTB4-BLT1 pathway offers innovative therapeutic opportunities especially in patients with asthma that remain uncontrolled despite intensive corticosteroid treatment. [ABSTRACT FROM AUTHOR]

To monitor the health of cells, the immune system tasks antigen-presenting cells with gathering antigens from other cells and bringing them to CD8 T cells in the form of peptides bound to MHC-I molecules. Most cells would be unable to perform this function because they use their MHC-I molecules to exclusively present peptides derived from the cell's own proteins. However, the immune system evolved mechanisms for dendritic cells and some other phagocytes to sample and present antigens from the extracellular milieu on MHC-I through a process called cross-presentation. How this important task is accomplished, its role in health and disease, and its potential for exploitation are the subject of this review. [ABSTRACT FROM AUTHOR]

Despite extensive research, influenza A virus (IAV) remains a major cause of morbidity, mortality, and healthcare expenditure. Emerging pandemics from highly pathogenic IAV strains such as H5N1 and pandemic H1N1 highlight the need for universal, cross-protective vaccines. Current vaccine formulations generate strain-specific neutralizing antibodies primarily against the outer coat proteins hemagglutinin and neuraminidase. In contrast to these highly mutable proteins, internal proteins of IAV are more conserved and are a favorable target for developing vaccines that induce strong T cell responses in addition to humoral immunity. Here, we found that intranasal administration with a single dose of CpG and inactivated x31 (H3N2) reduced viral titers and partially protected mice from a heterosubtypic challenge with a lethal dose of PR8 (H1N1). Early after immunization, vaccinated mice showed increased innate immune activation with high levels of MHCII and CD86 expression on dendritic cells in both the draining lymph nodes and lungs. Three days after immunization, CD4 and CD8 cells in the lung upregulated CD69, suggesting that activated lymphocytes are present at the site of vaccine administration. The ensuing effector Th1 responses were capable of producing multiple cytokines and were present at least 30 days after immunization. Furthermore, functional memory responses were observed, as antigen specific IFN-γ+ and GrB+ cells were detected early after lethal infection. Together, this work provides evidence for using pattern recognition receptor agonists as a mucosal vaccine platform for inducing robust T cell responses capable of protecting against heterologous IAV challenges.

Toxoplasma gondii infection induces a strong and long-lasting immune response that is able to prevent most reinfections but allows tissue cysts. Irradiated, sterilized T. gondii tachyzoites are an interesting vaccine, and they induce immunity that is similar to infection, but without cysts. In this study, we evaluated the cellular immune response in the blood and spleen of mice immunized with this preparation by mouth (v.o.) or intraperitoneally (i.p.) and analyzed the protection after challenge with viable parasites. BALB/c mice were immunized with three i.p. or v.o. doses of irradiated T. gondii tachyzoites. Oral challenge with ten cysts of the ME-49 or VEG strain at 90 days after the last dose resulted in high levels of protection with low parasite burden in the immunized animals. There were higher levels of specific IgG, IgA and IgM antibodies in the serum, and the i.p. immunized mice had higher levels of the high-affinity IgG and IgM antibodies than the orally immunized mice, which had more high-affinity IgA antibodies. B cells (CD19), plasma cells (CD138) and the CD4 and CD8 T cell populations were increased in both the blood and spleen. Cells from the spleen of the i.p. immunized mice also showed antigen-induced production of interleukin-10 (IL-10), interferon gamma (IFN-γ) and interleukin 4 (IL-4). The CD4 T cells, B cells and likely CD8 T cells from the spleens of the i.p. immunized mice proliferated with a specific antigen. The protection was correlated with the spleen and blood CD8 T cell, high-affinity IgG and IgM and antigen-induced IL-10 and IL-4 production. Immunization with irradiated T. gondii tachyzoites induces an immune response that is mediated by B cells and CD4 and CD8 T cells, with increased humoral and cellular immune responses that are necessary for host protection after infection. The vaccine is similar to natural infection, but free of tissue cysts; this immunity restrains infection at challenge and can be an attractive and efficient model for vaccine development in toxoplasmosis. [ABSTRACT FROM AUTHOR]

Ectromelia virus is a mouse-specific orthopoxvirus that, following footpad infection or natural transmission, causes mousepox in most strains of mice, while a few strains, such as C57BL/6, are resistant to the disease but not to the infection. Mousepox is an acute, systemic, highly lethal disease of remarkable semblance to smallpox, caused by the human-specific variola virus. Starting in 1929 with its discovery by Marchal, work with ECTV has provided essential information for our current understanding on how viruses spread lympho-hematogenously, the genetic control of antiviral resistance, the role of different components of the innate and adaptive immune system in the control of primary and secondary infections with acute viruses, and how the mechanisms of immune evasion deployed by the virus affect virulence in vivo. Here, I review the literature on the pathogenesis and immunobiology of ECTV infection in vivo. [ABSTRACT FROM AUTHOR]

Adoptive T cell therapy of cancer employs a large number of ex-vivo-propagated T cells which recognize their targets either by virtue of their endogenous T cell receptor (TCR) or via genetic reprogramming. However, both cell-extrinsic and intrinsic mechanisms often diminish the in-vivo potency of these therapeutic T cells, limiting their clinical efficacy and broader use. Direct activation of human T cells by Toll-like receptor (TLR) ligands induces T cell survival and proliferation, boosts the production of proinflammatory cytokines and augments resistance to regulatory T cell (Treg) suppression. Removal of the TLR ligand-binding region results in constitutive signalling triggered by the remaining cytosolic Toll/interleukin-1 receptor (TIR) domain. The use of such TIR domains therefore offers an ideal means for equipping anti-tumour T cells with the arsenal of functional attributes required for improving current clinical protocols. Here we show that constitutively active (ca)TLR-4 can be expressed efficiently in human T cells using mRNA electroporation. The mere expression of caTLR-4 mRNA in polyclonal CD8 and CD4 T cells induced the production of interferon (IFN)-γ, triggered the surface expression of CD25, CD69 and 4-1BB and up-regulated a panel of cytokines and chemokines. In tumour-infiltrating lymphocytes prepared from melanoma patients, caTLR-4 induced robust IFN-γ secretion in all samples tested. Furthermore, caTLR-4 enhanced the anti-melanoma cytolytic activity of tumour-infiltrating lymphocytes and augmented the secretion of IFN-γ, tumour necrosis factor (TNF)-α and granulocyte-macrophage colony-stimulating factor (GM-CSF) for at least 4 days post-transfection. Our results demonstrate that caTLR-4 is capable of exerting multiple T cell-enhancing effects and can potentially be used as a genetic adjuvant in adoptive cell therapy. [ABSTRACT FROM AUTHOR]

Despite extensive research, influenza A virus (IAV) remains a major cause of morbidity, mortality, and healthcare expenditure. Emerging pandemics from highly pathogenic IAV strains such as H5N1 and pandemic H1N1 highlight the need for universal, cross-protective vaccines. Current vaccine formulations generate strain-specific neutralizing antibodies primarily against the outer coat proteins hemagglutinin and neuraminidase. In contrast to these highly mutable proteins, internal proteins of IAV are more conserved and are a favorable target for developing vaccines that induce strong T cell responses in addition to humoral immunity. Here, we found that intranasal administration with a single dose of CpG and inactivated x31 (H3N2) reduced viral titers and partially protected mice from a heterosubtypic challenge with a lethal dose of PR8 (H1N1). Early after immunization, vaccinated mice showed increased innate immune activation with high levels of MHCII and CD86 expression on dendritic cells in both the draining lymph nodes and lungs. Three days after immunization, CD4 and CD8 cells in the lung upregulated CD69, suggesting that activated lymphocytes are present at the site of vaccine administration. The ensuing effector Th1 responses were capable of producing multiple cytokines and were present at least 30 days after immunization. Furthermore, functional memory responses were observed, as antigen specific IFN-γ+ and GrB+ cells were detected early after lethal infection. Together, this work provides evidence for using pattern recognition receptor agonists as a mucosal vaccine platform for inducing robust T cell responses capable of protecting against heterologous IAV challenges. [ABSTRACT FROM AUTHOR]

Arthropod-borne obligately intracellular bacteria pose a difficult challenge to the immune system. The genera Rickettsia, Orientia, Ehrlichia, and Anaplasma evolved mechanisms of immune evasion, and each interacts differently with the immune system. The roles of CD8 T cells include protective immunity and immunopathology. In Rickettsia infections, CD8 T cells are protective mediated in part by cytotoxicity toward infected cells. In contrast, TNF-α overproduction by CD8 T cells is pathogenic in lethal ehrlichiosis by induction of apoptosis/necrosis in hepatocytes. Yet, CD8 T cells, along with CD4 T cells and antibodies, also contribute to protective immunity in ehrlichial infections. In granulocytic anaplasmosis, CD8 T cells impact pathogen control modestly but could contribute to immunopathology by virtue of their dysfunction. While preliminary evidence indicates that CD8 T cells are important in protection against Orientia tsutsugamushi, mechanistic studies have been neglected. Valid animal models will enable experiments to elucidate protective and pathologic immune mechanisms. The public health need for vaccines against these agents of human disease, most clearly O. tsutsugamushi, and the veterinary diseases, canine monocytotropic ehrlichiosis ( Ehrlichia canis), heartwater ( Ehrlichia ruminantium), and bovine anaplasmosis ( A. marginale), requires detailed immunity and immunopathology investigations, including the roles of CD8 T lymphocytes. [ABSTRACT FROM AUTHOR]

CD8 T cells contribute to protective immunity against Mycobacterium tuberculosis. In humans, M. tuberculosis reactive CD8 T cells typically recognize peptides associated to classical MHC class Ia molecules, but little information is available on CD8 T cells recognizing M. tuberculosis Ags presented by nonclassical MHC class Ib molecules. We show here that CD8 T cells from tuberculosis (TB) patients recognize HLA-E-binding M. tuberculosis peptides in a CD3/TCR αβ mediated and CD8-dependent manner, and represent an additional type of effector cells playing a role in immune response to M. tuberculosis during active infection. HLA-E-restricted recognition of M. tuberculosis peptides is detectable by a significant enhanced ex vivo frequency of tetramer-specific circulating CD8 T cells during active TB. These CD8 T cells produce type 2 cytokines upon antigenic in vitro stimulation, help B cells for Ab production, and mediate limited TRAIL-dependent cytolytic and microbicidal activity toward M. tuberculosis infected target cells. Our results, together with the finding that HLA-E/ M. tuberculosis peptide specific CD8 T cells are detected in TB patients with or without HIV coinfection, suggest that this is a new human T-cell population that participates in immune response in TB. [ABSTRACT FROM AUTHOR]

CD103 plays an important role in the destruction of islet allografts, and previous studies found that a CD103 immunotoxin (M290-Saporin, or M290-SAP) promoted the long-term survival of pancreatic islet allografts. However, systemic toxicity to the host and the bystander effects of M290-SAP obscure the underlying mechanisms of action and restrict its clinical applications. To overcome these shortcomings, anti-CD103 M290 was conjugated to different cytotoxic agents through cleavable or uncleavable linkages to form three distinct antibody–drug conjugates (ADCs): M290-MC-vc-PAB-MMAE, M290-MC-MMAF, and M290-MCC-DM1. The drug-to-antibody ratio (DAR) and the purity of the ADCs were determined by HIC–HPLC and SEC–HPLC, respectively. The binding characteristics, internalization and cytotoxicity of M290 and the corresponding ADCs were evaluated in vitro. The cell depletion efficacies of the various M290–ADCs against CD103-positive cells were then evaluated in vivo. The M290–ADCs maintained the initial binding affinity for the CD103-positive cell surface antigen and then quickly internalized the CD103-positive cell. Surprisingly, all M290–ADCs potently depleted CD103-positive cells in vivo, with high specificity and reduced toxicity. Our findings show that M290–ADCs have potent and selective depletion effects on CD103-expressing cells in immunocompetent mice. These data indicate that M290–ADCs could potentially serve as a therapeutic intervention to block the CD103/E-cadherin pathway. [ABSTRACT FROM AUTHOR]

Background: Many studies on T helper (Th)1, Th2, T regulatory and Th17 cells have been carried out in acute-on-chronic liver failure (ACLF). However, CD8 T cell, as a main participant in immune-mediated injuries and defense against microorganisms, has seldom been studied in ACLF. Aims: The purpose of this study was to investigate the CD8 T cell function, and the outcomes of patients with severe hepatitis [SH; serum bilirubin (SB) ≥10 mg/dl and prothrombin activity (PTA) <60 %]. Methods: Thirty-six patients with chronic HBV-associated SH were included. Twenty normal chronic hepatitis B (CHB) patients (2 < SB < 10 (mg/dl) and PTA ≥ 60 %) and 28 healthy volunteers were enrolled as control groups. Results: Twenty-six patients with SH were diagnosed with ACLF (SB ≥ 10 mg/dl and PTA ≤ 40 %). The non-recovered ACLFs (NR-ACLF) had higher HBV DNA loads than recovered ACLFs (R-ACLF) (6.03 ± 1.79 vs. 4.36 ± 1.61 (log, IU/L)). The NR-ACLFs had the highest neutrophil:lymphocyte ratios (5.10 ± 2.37) (all P < 0.001; a = 0.05). The CHBs had higher perforin and T (CD45RACD62LCCR7) proportions [31.28 ± 19.51, 5.32 ± 3.57 (%)] compared to R-ACLFs (11.75 ± 15.35, 0.78 ± 0.76 (%); P = 0.004, 0.001, respectively), or NR-ACLFs (11.61 ± 5.79, 1.14 ± 0.67 (%); P = 0.006, 0.003). The non-ACLF SHs had higher CD38 proportions than R-ACLFs or NR-ACLFs (25.46 ± 8.02 vs. 16.24 ± 7.77 or 16.81 ± 6.30 (%), P = 0.039, 0.023). Conclusions: High neutrophil:lymphocyte ratios and a decrease in activated CD8 T cells may be related to poor outcomes in patients with SH. [ABSTRACT FROM AUTHOR]

The pathogenesis of hemorrhagic fever with renal syndrome (HFRS) has not been fully clarified. Cell-mediated immunity appears to play a crucial role in the immune pathogenesis of HFRS. To explore the relationship between Hantaan (HTNV)-specific CD8 T lymphocytes and the immune pathogenesis of HFRS, the levels of interferon γ (IFN-γ) secreted by HTNV-specific CD8 T lymphocytes were detected by flow cytometry in peripheral blood mononuclear cells. Levels of HTNV-specific CD8 T lymphocytes in patients with HFRS were associated with different phases of HFRS. In fever phase, it was significantly elevated. The levels of HTNV-specific CD8 T lymphocytes in PBMC of patients with HFRS were negatively correlated with the levels of blood urea nitrogen and creatinine in plasma. The results show that the HTNV-specific CD8 T lymphocyte levels correlate with disease phases. Therefore, dynamic observation of these levels in patients with HFRS can help to judge the status of HFRS disease and to clarify the immune pathogenesis of HFRS. [ABSTRACT FROM AUTHOR]

Studies indicated that CC receptor 5 (CCR5), as a receptor for CC ligand 3, CCL4, and CCL5, plays important roles in the recruitment of T cytotoxic lymphocytes to the liver of chronic HBV (CHB)-infected patients. The main purpose of this study was to investigate the expression levels of CCR5 on the CD8 T lymphocytes of CHB patients. This clinical study was performed on 63 CHB patients and 96 healthy controls. Flow cytometric analysis was performed to examine the expression of CCR5 on CD8 T cells of CHB patients. Real-time PCR was also used for HBV-DNA quantification. The results of our study demonstrated that CCR5 expressing T cytotoxic cells were decreased significantly in CHB patients in comparison to healthy control. Based on our results, it can be concluded that the percent of CCR5/CD8 T cells in Iranian CHB patients is significantly decreased, hence their migration to the infected liver, and HBV eradication from the hepatocytes is disrupted. [ABSTRACT FROM AUTHOR]

Pathogenic yeast and fungi represent a major group of human pathogens. The consequences of infections are diverse and range from local, clinically uncomplicated mycosis of the skin to systemic, life-threatening sepsis. Despite extensive MHC class I-restricted frequencies of yeast-specific CD8 T lymphocytes in healthy individuals and the essential role of the cell-mediated immunity in controlling infections, the characteristics and defense mechanisms of antifungal effector cells are still unclear. Here, we describe the direct analysis of yeast-specific CD8 T lymphocytes in whole blood from healthy individuals. They show a unique, nonclassical phenotype expressing granulysin and granzyme K in lytic granules instead of the major effector molecules perforin and granzyme B. After stimulation in whole blood, yeast-specific CD8 T cells degranulated and, upon cultivation in the presence of IL-2, their granula were refilled with granulysin rather than with perforin and granzyme B. Moreover, yeast-specific stimulation through dendritic cells but not by yeast cells alone led to degranulation of the effector cells. As granulysin is the only effector molecule in lytic granules known to have antifungal properties, our data suggest yeast-specific CD8 T cells to be a nonclassical effector population whose antimicrobial effector machinery seems to be tailor-made for the efficient elimination of fungi as pathogens. [ABSTRACT FROM AUTHOR]

Background: The prevalence of chronic rhinitis is increasing rapidly; its pathogenesis is to be further understood; immune inflammation is one of the possible causative factors. Antigen specific CD8+ T cells play a critical role in the induction of chronic inflammation. Aims: This study aimed to investigate the role of antigen specific CD8+ T cells in the pathogenesis of chronic atypical allergic rhinitis. Material and Methods: Nasal mucosal epithelial surface scratching samples were obtained from patients with chronic obstruction atypical allergic rhinitis. Exosomes were purified from the scratching samples and examined by immune gold electron microscopy. The effect of exosomes on modulating dendritic cell's properties, the effect of exosome-pulsed dendritic cells on naïve T cell differentiation and the antigen specific CD8+ T cell activation were observed by cell culture models. Results: Exosomes purified from patients with chronic atypical allergic rhinitis carried microbial products, Staphylococcal enterotoxin B (SEB), and airborne antigen, Derp1. Dendritic cells pulsed by SEB/Derp1-carrying exosomes showed high levels of CD80, CD86 and the major histocompatibility class I (MHCI). Exosome-pulsed dendritic cells could induce the naïve CD3+ T cells to differentiate into CD8+ T cells. Upon the exposure to a specific antigen, the CD8+ T cells released granzyme B and perforin; more than 30% antigen specific CD8+ T cells proliferated. Conclusions: Antigen specific CD8+ T cells play an important role in the pathogenesis of chronic obstruction atypical allergic rhinitis. [ABSTRACT FROM AUTHOR]

Abstract: Natural killer (NK) and CD8+ T cells may be active elements in the allograft response, but little is known about their role in liver transplantation. Some of these cells express killer immunoglobulin-like receptors (KIRs), which after binding specific ligands may transmit inhibitory/activating signals. In this study, circulating NK and CD8+ T cells expressing CD158a/h (KIR2DL1/S1) or CD158b/j (KIR2DL2/3/S2) receptors were analyzed in 142 liver recipients by flow cytometry. They were underrepresented in patients before transplantation, but following transplantation, whereas the KIR2D+ NK subsets experienced a late recuperation (day 365) mainly in C2-homozygous patients developing early acute rejection, recovery of the 2 CD8+KIR2D+ T cells started earlier, showing significant differences on day 365 between patients without acute rejection and those suffering from it (p = 0.004 and p < 0.0001, respectively). These differences were also evident when the human leukocute antigen-C genotypes of the recipient were considered. In conclusion, whereas the late recovery of KIR2D+ NK cells in C2/C2 patients appears to be linked to acute rejection, the increase in early CD8+KIR2D+ T cells in overall liver recipients correlates with a most successful early graft outcome. Therefore, monitoring of KIR2D+ cells appears to be a useful tool for liver transplant follow-up. [Copyright &y& Elsevier]

Abstract: Infection with human immunodeficiency virus (HIV)–1 induces a progressive deterioration of the immune system that ultimately leads to aquired immune deficiency syndrome (AIDS). Murine models indicate that the common γ-chain (γc)–sharing cytokine interleukin (IL)–21 and its receptor (IL-21R) play a crucial role in maintaining polyfunctional T cell responses during chronic viral infections. Therefore, we analyzed the ability of this cytokine to modulate the properties of human CD8 T cells in comparison with other γc-sharing cytokines (IL-2, IL-7, and IL-15). CD8 T cells from healthy volunteers were stimulated in vitro via T cell receptor signals to mimic the heightened status of immune activation of HIV-infected patients. The administration of IL-21 upregulated cytotoxic effector function and the expression of the costimulatory molecule CD28. Notably, this outcome was not accompanied by increased cellular proliferation or activation. Moreover, IL-21 promoted antiviral activity while not inducing HIV-1 replication in vitro. Thus, IL-21 may be a favorable molecule for immunotherapy and a suitable vaccine adjuvant in HIV-infected individuals. [ABSTRACT FROM AUTHOR]

Type 1 diabetes (T1D) occurs because of lack of T cell tolerance to islet antigens. We hypothesized that critical genetic susceptibility loci that control progression to T1D, designated as insulin-dependent diabetes ( Idd) loci, would be responsible for preventing CD8 T cell tolerance. To test this hypothesis, we have used two different congenic non-obese diabetic (NOD) mice that are highly protected from the occurrence of T1D because they express protective alleles at Idd3 and Idd5.1, 5.2, 5.3 (Idd3/5 mice), or at Idd9.1, 9.2, and 9.3 ( Idd9 mice). By examining the CD8 T response to two different islet-expressed antigens, we have determined that CD8 T tolerance is restored in both strains of mice. However, tolerance occurs at different checkpoints in each strain. In Idd3/5 mice, islet-antigen-specific CD8 T cells are eliminated in the pancreatic lymph nodes, where they are first activated by cross-presented islet antigens. In contrast, in Idd9 mice autoreactive CD8 T cells accumulate at this site and are not tolerized until after they enter the pancreas. We are currently identifying the cell types and mechanisms that are critical for tolerance induction at each checkpoint. [ABSTRACT FROM AUTHOR]

Abstract: Adenoviruses (Ads) cause fatal disease in allogeneic stem cell transplant recipients, but there is no established therapy. Ad-specific CD8+ T cells were detected in PBMC from healthy adults at a mean frequency of 77 per 105 CD8+ T cells (range 8–260) by interferon-γ ELISPOT and cytokine flow cytometry assays. CD8+ T cell lines from 7 of 7 donors exhibited MHC-class-I-restricted killing of targets expressing the capsid protein hexon. In contrast, cytotoxicity against the capsid proteins fiber and penton base was weaker or not detected. Two HLA-A2-restricted hexon epitopes and one HLA-B-restricted epitope were identified, all of which are adjacent to or overlap an HLA-DP4-restricted epitope in the highly conserved C-terminus. Thus, hexon is the immunodominant T cell target among capsid proteins and contains multiple C-terminal epitopes conserved among serotypes. These data support evaluation of donor lymphocyte infusions for treatment of Ad disease post-transplant. [Copyright &y& Elsevier]

The article reports on the effects of antiretroviral therapy on HIV-infected patients. The patients administered with increase in plasma IL-7 levels showed T-cell pool decrease progressively in HIV-infected patients. The cell surface expression of CD127 was measured ex vivo in CD4 and CD8 T lymphocytes drawn from 3 groups of HIV patients. The reason for the dysfunctional of IL-7 receptor in HIV patients are due to the abnormal activation of the immune system of the individual.

5T4 is a surface glycoprotein expressed on placental trophoblasts and also on a wide range of human carcinomas. Its highly restricted expression on normal tissues and broad distribution on many carcinomas make 5T4 a promising target for cancer immunotherapy. In the current study, we set out to investigate whether a 5T4-specific cytotoxic T lymphocyte (CTL) repertoire exists in healthy individuals. CD4-depleted peripheral blood mononuclear cells (PBMCs) from blood donors were screened using an ex vivo interferon-γ (IFN-γ) enzyme-linked immunospot (ELISPOT) assay. A panel of overlapping peptides, spanning the full length of the 5T4 protein, was used as a source of antigen. In the process of screening, one out of 30 blood donors demonstrated a positive ex vivo IFN-γ ELISPOT response to a single 5T4 peptide. A polyclonal T-cell line was derived from this donor by culturing PBMCs with autologous peptide-pulsed dendritic cells (DCs). The resulting polyclonal T-cell line and clones were tested in a 51Cr-release assay and by ELISPOT and were shown to be peptide specific. Furthermore, antigen-presenting cells (APCs), infected with a viral vector expressing 5T4, were able to stimulate IFN-γ production by the peptide-specific T-cell clones. A minimal CD8 epitope, PLADLSPFA, has been identified and found to be restricted through human leucocyte antigen (HLA) Cw7. Subsequently, we have demonstrated that HLA-Cw7-positive colorectal cancer patients vaccinated with a recombinant vaccinia viral vector encoding 5T4 (TroVax) are capable of mounting a strong IFN-γ ELISPOT response to this novel CTL epitope. These findings have potential application in cancer immunotherapy in terms of subunit vaccine design and the monitoring of immune responses induced in patients by 5T4-based therapies. [ABSTRACT FROM AUTHOR]

Abstract: Clinical and epidemiologic features of Kawasaki Disease (KD) point to an infectious cause, most likely a single etiologic agent or a closely related group of agents. In acute Kawasaki Disease, both the T- and B-lymphocyte immune responses, the cornerstones of acquired immunity, are oligoclonal, indicating a response to a conventional antigen rather than a superantigen. We have prepared synthetic oligoclonal Kawasaki Disease antibodies in vitro and have demonstrated binding of one synthetic monoclonal antibody to an intracellular antigen present in bronchial epithelium and in a subset of macrophages in tissues from children with acute Kawasaki Disease. Further characterization of this antigen may lead to the development of a diagnostic test, improved therapy, and prevention of this potentially fatal childhood illness. [Copyright &y& Elsevier]

Fuchs heterochromic cyclitis (FHC) is characterized by a predominant CD8+ T cell subset infiltrating the anterior chamber, but the clonal composition of these T cells is unknown. In the present study, T cell repertoire diversity of the accumulating T cells was analyzed to investigate if a high degree of restriction could indicate antigen-driven immune response.Aqueous humor (AH) and peripheral blood cells were collected in two patients with FHC. T cell repertoire diversity was screened by T cell receptor (TCR) BV family expression. In one patient, several BV gene segments were used by lymphocytes from the AH but with over-representation of BV16 that accounted for around half of the expressed intraocular repertoire. In the other patient, a more restricted TCRBV usage was found in AH, as only BV15 and BV18 were expressed in the ocular sample. In this patient, virtually all AH CD8− T-cells were CD28- and CD57-negative by three-color flow cytometry, an immunophenotype suggestive of past antigenic stimulation. High resolution immunoscope analysis of TCRBV CDR3 profiles and sequencing of subcloned TCRBV-BJ PCR products evidenced a highly restricted TCRBV-BJ usage, since virtually all the intraocular cells comprise only five clonotypes in this patient. Unique peaks of CDR3 length were found in BV15 joined to BJ2S1, BJ2S3 and especially BJ2S5, in AH but did not predominate in blood. Conversely, identical clonotypes using rearranged BV18 and BJ2S7 gene segments were detected in both AH and peripheral blood. Maintenance of the TCRBV18-BJ2S7 clonotypes in aqueous humor was demonstrated over 6 months in this patient, with a switch in the predominance of two clonotypes.Our results show the presence of a finite number of CD8+CD28neg T cell clonotypes, which suggests an antigen-driven process and the involvement of these T cells in the pathogenesis of FHC. [Copyright &y& Elsevier]

We tested the ability of an attenuated actA mutant of to induce protective immunity in mice. This mutant can enter and multiply in the cytosol of the infected host cell, but is deficient in actin-dependent cell-to-cell spread. It was found to be of attenuated virulence for inbred C3H mice: the LD after I.v. injection was 1000-fold higher than that of the wild-type strain. Mutant bacteria multiplied up to the fourth day in the liver, but only for 1 day in the spleen. A single infection with the maximum sublethal dose of the mutant induced long-lasting immunity; the LD of virulent wild-type increased 100-fold and growth of wild-type was controlled In liver and spleen of these mice. The presence of Listeria-reactive T cells In spleen of C3H mice infected 7 days previously with the actA mutant was monitored, through their ability to protect naive syngeneic recipients against wild-type . Protection was mainly conferred by Thy-1CDB T lymphocytes; depletion of CD4 T cells had no significant effect on the level of transferred protection. Such attenuated mutants may be used to develop live vector vaccines for delivery of heterologous proteins into the cytosol, thereby favoring the induction of a CD8 T cell response. [ABSTRACT FROM PUBLISHER]

Tumor-associated tertiary lymphoid structures (TA-TLS) are associated with enhanced patient survival and responsiveness to cancer therapies, but the mechanisms underlying their development are unknown. We show here that TA-TLS development in murine melanoma is orchestrated by cancer-associated fibroblasts (CAF) with characteristics of lymphoid tissue organizer cells that are induced by tumor necrosis factor receptor signaling. CAF organization into reticular networks is mediated by CD8 T cells, while CAF accumulation and TA-TLS expansion depend on CXCL13-mediated recruitment of B cells expressing lymphotoxin-α 1 β 2. Some of these elements are also overrepresented in human TA-TLS. Additionally, we demonstrate that immunotherapy induces more and larger TA-TLS that are more often organized with discrete T and B cell zones, and that TA-TLS presence, number, and size are correlated with reduced tumor size and overall response to checkpoint immunotherapy. This work provides a platform for manipulating TA-TLS development as a cancer immunotherapy strategy. [Display omitted] • Cancer-associated fibroblasts orchestrate tertiary lymphoid structures in tumors • CD8 T cells and B cells drive tertiary lymphoid structure development via fibroblasts • Tertiary lymphoid structure development is mediated by TNF and lymphotoxin receptors • Checkpoint blockade alters tertiary lymphoid structures together with tumor control Rodriguez et al. describe the cellular and molecular mechanisms driving development of tumor-associated tertiary lymphoid structures and the importance of these structures as mediators of anti-tumor immunity and response to checkpoint immunotherapy. [ABSTRACT FROM AUTHOR]

Tumor antigens NY-ESO-1 and p53 both frequently induce spontaneous serum antibody in cancer patients. While NYESO- 1-specific CD8+ and CD4+ circulating T-cells occur mainly in NY-ESO-1-seropositive patients, p53-specific circulating CD8+ and CD4+ T-cells are respectively undetectable and common in most individuals. Understanding T-cell split tolerance can help define suitable targets for immunotherapy. [ABSTRACT FROM AUTHOR]

• p722-LNC induces a significant decrease of B16F10 melanoma cell viability. • p722-LNC slows tumor growth and improves the survival of treated mice. • p722-LNC potentiates intrinsic apoptotic pathway and activates CD8+ T lymphocytes. Metastatic melanoma is a malignant tumor with a poor prognosis. Recent new therapeutics improved the survival of patients at a metastatic stage. However, the low response rate to immunotherapy, explained in part by resistance to apoptosis, needs to develop new strategies. The ferrocifen family represents promising bioorganometallic molecules for melanoma treatment since they show potent anticancer properties. The aim of this study is (i) to evaluate the benefits of a strategy involving encapsulated p722 in lipid nanocapsules (LNC) in B16F10 melanoma mice models and (ii) to compare the beneficial effects with an existing therapy such as anti-CTLA4 mAb. Interestingly, LNC-p722 induces a significant decrease of melanoma cell viability. In vivo data shows a significant improvement in the survival rate and a slower tumor growth with p722-loaded LNC in comparison with anti-CTLA4 mAb. Western blots confirm that LNC-p722 potentiates intrinsic apoptotic pathway. Treatment with LNC-p722 significantly activates CD8+ T lymphocytes compared to treatment with anti-CTLA4 mAb. This study uncovers a new therapeutic strategy with encapsulated p722 to prevent B16F10 melanoma growth and to improve survival of treated mice. [ABSTRACT FROM AUTHOR]