Search

We have rapidly gained insights into the presence and function of T lymphocytes in non‐lymphoid tissues, the tissue‐resident memory T (TRM) cells. The central pillar of adaptive immunity has been expanded from classic central memory T cells giving rise to progeny upon reinfection and effector memory cells circulating through the blood and patrolling the tissues to include TRM cells that reside and migrate inside solid organs and tissues. Their development and maintenance have been studied in detail, providing exciting clues on how their unique properties used to fight infections may benefit therapies against solid tumors. We provide an overview of CD8 TRM cells and the properties that make them of interest for vaccination and cancer therapies. [ABSTRACT FROM AUTHOR]

Background Primary cutaneous acral CD8+ T-cell lymphoproliferative disorder (TLPD) is a rare and indolent lymphoma entity. Although TLPD was first identified many years ago, the molecular pathogenesis is still not fully understood. Objectives In order to better understand the molecular pathogenesis of cutaneous acral CD8+ TLPD and to identify further discriminatory markers to differentiate this lymphoma subtype from other CD8+ cutaneous lymphomas, we analysed five cases of cutaneous acral CD8+ TLPD for putative molecular alterations. Methods Somatic alterations were assessed using whole-exome and targeted sequencing of paraffin-embedded tissue. Results were evaluated using immunohistochemical staining of respective relevant proteins. CD8+ cutaneous T-cell lymphomas (n = 12) served as control for KIR3DL1 staining. Results Copy number variation analysis revealed a homozygous deletion of the KIR3DL1 gene in two of the analysed cases. This resulted in loss of KIR3DL1 protein expression, which was observed in all cases of cutaneous acral CD8+ TLPD. In contrast, KIR3DL1 expression was more variable in other CD8+ cutaneous T-cell lymphomas with 50% of analysed cases (n = 12) found to be positive. In addition, one further case of acral CD8+ TLPD harboured a loss-of-function mutation in the PIK3R1 gene, presumably activating the phosphoinositide 3-kinase-AKT pathway. Conclusions Alterations of the KIR3DL1 gene may be of pathogenetic relevance for acral CD8+ TLPD. Loss of KIR3DL1 protein expression may support the diagnosis of this indolent lymphoma entity; however, this is not a subtype-specific discriminative feature. [ABSTRACT FROM AUTHOR]

CD8+ T cells are integral to the effective management of cancer and infectious diseases due to their cytotoxic functions. The efficacy of these cells is profoundly influenced by their metabolic state, which regulates their activation, differentiation, and longevity. Accordingly, the modulation of metabolic pathways within CD8+ T cells is crucial for enhancing the effectiveness of T cell-based immunotherapy. Precise metabolic control is paramount in optimizing therapeutic outcomes and minimizing potential toxicities associated with treatment. Importantly, the potential of exogenous metabolites to augment CD8+ T cell responses is critically evaluated, especially through in vivo evidence that underscores their therapeutic promise. This review also addresses current challenges, including the need for precise control of metabolic modulation to avoid adverse effects, the development of targeted delivery systems to ensure efficient metabolite delivery to CD8+ T cells, and the inherent variability of metabolic states among patients that may influence treatment outcomes. Addressing these hurdles will be crucial for the successful integration of metabolic interventions into established immunotherapeutic regimens. [ABSTRACT FROM AUTHOR]

Transcription factor GATA3 is essential for the developmental processes of T cells. Recently, the silencer of a cytokine IFNγ gene was identified, the inhibitory activity of which requires GATA3. GATA3 has 2 Zn fingers and the commonly used GATA3 deficient mice lack both fingers (D2). We have established a mouse line that lacks only one Zn finger close to the C terminus (D1). The D1 mice line developed dermatitis, which was not observed in D2 mice. The expression of S100a8/S100a9 was elevated in D1 to a level higher than in D2, suggesting their roles in dermatitis development. CD8 T cells of both D1 and D2 lines expressed inhibitory receptors associated with the exhausted state. In the absence of MHC class II, the skin inflammation was exacerbated in both lines. The gene expression pattern of CD8 T cells became similar to that of effector T cells. Blocking Ab against LAG3 upregulated the expression of the effector molecules of T cells. These results suggest that the disfunction of GATA3 can lead to the spontaneous activation of CD8 T cells that causes skin inflammation, and that suppressive activity of MHC class II ‐ LAG3 interaction ameliorates dermatitis development. [ABSTRACT FROM AUTHOR]

Relapse after immunosuppression (IS) treatment withdrawal is frequent in patients with Autoimmune Hepatitis (AIH), and non-invasive biomarkers predictive of this risk are lacking. We assessed the frequency of circulating T cell subsets as potential biomarkers of disease activity and predictor of the risk of relapse after IS withdrawal. Serum levels of the cytokine B-cell Activating Factor (BAFF) were also investigated. Blood samples from 58 patients with active AIH, 56 AIH patients in remission, and 31 patients with NASH were analyzed. The frequency of activated CD4+ T peripheral helper (TPH) cells (CD4+CD45RA-CXCR5-PD1+CD38+) and of activated CD8+ T cells (CD8+CD45RA-PD1+CD38+) were assessed by flow cytometry. BAFF levels were determined by ELISA. Activated TPH and CD8+ T cell frequencies were significantly increased in patients with active AIH compared to remission AIH or NASH (TPH: 0.88% of total CD3+ vs. 0.42% and 0.39% respectively, p < 0.0001; CD8+ subset: 1.42% vs. 0.09% and 0.11% p < 0.0001). Among patients in remission undergoing treatment withdrawal (n = 18), those with increased frequencies of activated TPH (> 0.5% of total CD3+) and/or activated CD8+ T cells (> 0.18% total CD3+) had a higher risk of relapse (80% vs. 15% after 2 years, p = 0.0071). High BAFF serum concentration (> 213pg/ml) was also associated to a higher risk of relapse (57% vs. 11%, p = 0.0452). In conclusion, high frequency of activated TPH and of activated CD8+, as well as high levels of BAFF, before IS discontinuation, were significantly associated to a greater risk of relapse during the first two years. Thus, they represent promising biomarkers to provide personalized clinical follow-up for patients with AIH. [ABSTRACT FROM AUTHOR]

Background: Hepatitis B virus (HBV) clearance depends on an effective adaptive immune response, especially HBV-specific T cell-mediated cellular immunity; however, it is difficult to produce enough HBV-specific T cells effectively. Results: In this work, we investigated the proportions of stimulated cells, serum, and culture media as the three primary factors to determine the most effective procedure and applied it to HLA-A2 (+) people. In parallel, we also examined the correlation between clinical parameters and HBV-specific immunity. Concerning amplification efficiency, 4 × 105 cells stimulation was superior to 2 × 106 cells stimulation, AIM-V medium outperformed 1640 medium, and fetal bovine serum (FBS) exceeded human AB serum under comparable conditions. As expected, this procedure is also suitable for developing HBV-specific CD8 + T cells in HLA-A2(+) individuals. Expanded HBV-specific T cell responses decreased with treatment time and were negatively correlated with HBV DNA and HBsAg. Furthermore, the number of HBV-specific IFN-γ + SFCs was strongly correlated with the ALT level and negatively correlated with the absolute lymphocyte count and the ALB concentration. Conclusions: We confirm that stimulating 4 × 105 PBMCs in AIM-V medium supplemented with 10% FBS is the best approach and that HBeAg, HBsAg, and ALB are independent predictors of HBV-specific T-cell responses. [ABSTRACT FROM AUTHOR]

In hepatitis C virus (HCV) infection, CD4+ and CD8+ T cells are crucial for viral control. However, a detailed understanding of the kinetic of CD4+ T cell help and its role in the generation of different CD8+ T cell subsets during acute infection is lacking. The absence of a small HCV animal model has impeded mechanistic studies of hepatic antiviral T cell immunity and HCV vaccine development. In this study, we used a recently developed HCV-related rodent hepacivirus infection mouse model to investigate the impact of CD4+ T cell help on the hepatic CD8+ T cell response and viral clearance during hepacivirus infection in vivo. Our results revealed a specific kinetic of CD4+ T cell dependency during acute infection. Early CD4+ T cell help was essential for CD8+ T cell priming and viral clearance, while CD4+ T cells became dispensable during later stages of acute infection. Effector CD8+ T cells directly mediated timely hepacivirus clearance. An analysis of hepatic CD8+ T cells specific for two different viral epitopes revealed the induction of subsets of liver-homing CD103+CD49a+ and CD103-CD49a+ effector CD8+ T cells with elevated IFN-γ and TNF-α production. CD103+CD49a+ T cells further persisted as tissue-resident memory subsets. A lack of CD4+ T cell help and CD40L-CD40 interactions resulted in reduced effector functions and phenotypical changes in effector CD8+ T cells and a specific loss of the CD103+CD49a+ subset. In summary, our study shows that early CD4+ T cell help through CD40L signaling is essential for priming functional effector CD8+ T cell subsets, including unique liver-homing subsets, and hepacivirus clearance. Author summary: Chronic hepatitis C virus (HCV) infection affects about 58 million people worldwide and is a major cause for the development of end-stage liver disease. While chronic HCV infection can be cured, a prophylactic vaccine still does not exist. CD4+ and CD8+ T cells are important for HCV control, but a more in-depth understanding of the specific functions of T cell subsets during acute infection in the liver, the site of HCV infection, is needed for the development of effective vaccine strategies. Since access to human liver tissue is limited and HCV does not naturally infect mice, we previously developed a mouse model based on an HCV-related rodent hepacivirus. This model shares immunological features with human HCV infection and allows the study of antiviral immunity in the liver. In this study we used this model to assess the functional role of CD4+ and CD8+ T cell subsets during acute infection. We report a specific kinetic of CD4+ T cell dependent viral clearance and show that these cells provide critical help for the generation of unique liver-homing CD8+ T cell subsets. Overall, our study provides new insights into the determinates of hepacivirus clearance and immunity in the liver. [ABSTRACT FROM AUTHOR]

Lupus nephritis (LN) is a common clinical manifestation of systemic lupus erythematosus (SLE). Our study aims to quantitatively analyze CD4+ and CD8+ lymphocytes in different areas and LN classes and describe a specific distribution pattern that is correlated with the severity of LN-specific lesions. In total, 53 LN renal biopsies were immunohistochemically investigated using anti-CD4 and anti-CD8 antibodies. T lymphocytes were counted in 3 areas, including intraglomerular, periglomerular, and interstitial regions. The severity of glomerular and tubulo-interstitial lesions was assessed using an original semi-quantitative algorithm based on the renal corpuscle score (RC_S) and the tubulo-interstitial score (TI_S). The number of CD8+ T lymphocytes was higher than that of CD4+ T lymphocytes in each of the three areas and in each LN class, showing statistically significant differences. ANOVA analysis of all LN classes showed significant differences between periglomerular and interstitial CD4+ and CD8+ T lymphocytes, respectively. Irrespective of location, the number of CD8+ T lymphocytes statistically correlates with the RC_S and the TI_S; no significant correlations were found between the number of CD4+ T lymphocytes and the RC_S and the TI_S for all three considered areas. Our data provide strong evidence supporting the major role of CD8+ lymphocytes in LN lesion progression, with CD4+ lymphocytes playing a limited role. [ABSTRACT FROM AUTHOR]

The explicit identification of CD8+ T cell subpopulation is important for deciphering the role of CD8+ T cells for protecting our body against invading pathogens and cancer. Our generated monoclonal antibody (mAb), named FE‐1H10, recognized two novel subpopulations of peripheral blood CD8+ T cells, FE‐1H10+ and FE‐1H10− CD8+ T cells. The molecule recognized by mAb FE‐1H10 (FE‐1H10 molecules) had a higher distribution on effector memory CD8+ T cell subsets. The functions of FE‐1H10− and FE‐1H10+ CD8+ T cells were investigated. T cell proliferation assays revealed that FE‐1H10− CD8+ T cells exhibited a higher proliferation rate than FE‐1H10+ CD8+ T cells, whereas FE‐1H10+ CD8+ T cells produced higher levels of IFN‐γ and TNF‐α than FE‐1H10− CD8+ T cells. In T cell cytotoxicity assays, FE‐1H10+ CD8+ T cells were able to kill target cells better than FE‐1H10− CD8+ T cells. RNA‐sequencing analysis confirmed that these subpopulations were distinct: FE‐1H10+ CD8+ T cells have higher expression of genes involved in effector functions (IFNG, TNF, GZMB, PRF1, GNLY, FASL, CX3CR1) while FE‐1H10− CD8+ T cells have greater expression of genes related to memory CD8+ T cell populations (CCR7, SELL, TCF7, CD40LG). The results suggested that mAb FE‐1H10 identifies two novel distinctive CD8+ T cell subpopulations. The FE‐1H10+ CD8+ T cells carried a superior functionality in response to tumour cells. The uncover of these novel CD8+ T cell subpopulations may be the basis knowledge of an optional immunotherapy for the selection of potential CD8+ T cells in cancer treatment. [ABSTRACT FROM AUTHOR]

BACKGROUND. Teplizumab, a non-FcR-binding anti-CD3 mAb, is approved to delay progression of type 1 diabetes (T1D) in at-risk patients. Previous investigations described the immediate effects of the 14-day treatment, but longer-term effects of the drug remain unknown. METHODS. With an extended analysis of study participants, we found that 36% were undiagnosed or remained free of clinical diabetes after 5 years, suggesting operational tolerance. Using single-cell RNA sequencing, we compared the phenotypes, transcriptome, and repertoire of peripheral blood CD8+ T cells including autoreactive T cells from study participants before and after teplizumab and features of responders and non-responders. RESULTS. At 3 months, there were transcriptional signatures of cell activation in CD4+ and CD8+ T cells including signaling that was reversed at 18 months. At that time, there was reduced expression of genes in T cell receptor and activation pathways in clinical responders. In CD8+ T cells, we found increased expression of genes associated with exhaustion and immune regulation with teplizumab treatment. These transcriptional features were further confirmed in an independent cohort. Pseudotime analysis showed differentiation of CD8+ exhausted and memory cells with teplizumab treatment. IL7R expression was reduced, and patients with lower expression of CD127 had longer diabetes-free intervals. In addition, the frequency of autoantigenreactive CD8+ T cells, which expanded in the placebo group over 18 months, did not increase in the teplizumab group. CONCLUSION. These findings indicate that teplizumab promotes operational tolerance in T1D, involving activation followed by exhaustion and regulation, and prevents expansion of autoreactive T cells. [ABSTRACT FROM AUTHOR]

While most individuals suffer progressive disease following HIV infection, a small fraction spontaneously controls the infection. Although CD8 T-cells have been implicated in this natural control, their mechanistic roles are yet to be established. Here, we combined mathematical modeling and analysis of previously published data from 16 SIV-infected macaques, of which 12 were natural controllers, to elucidate the role of CD8 T-cells in natural control. For each macaque, we considered, in addition to the canonical in vivo plasma viral load and SIV DNA data, longitudinal ex vivo measurements of the virus suppressive capacity of CD8 T-cells. Available mathematical models do not allow analysis of such combined in vivo-ex vivo datasets. We explicitly modeled the ex vivo assay, derived analytical approximations that link the ex vivo measurements with the in vivo effector function of CD8-T cells, and integrated them with an in vivo model of virus dynamics, thus developing a new learning framework that enabled the analysis. Our model fit the data well and estimated the recruitment rate and/or maximal killing rate of CD8 T-cells to be up to 2-fold higher in controllers than non-controllers (p = 0.013). Importantly, the cumulative suppressive capacity of CD8 T-cells over the first 4–6 weeks of infection was associated with virus control (Spearman's ρ = -0.51; p = 0.05). Thus, our analysis identified the early cumulative suppressive capacity of CD8 T-cells as a predictor of natural control. Furthermore, simulating a large virtual population, our model quantified the minimum capacity of this early CD8 T-cell response necessary for long-term control. Our study presents new, quantitative insights into the role of CD8 T-cells in the natural control of HIV infection and has implications for remission strategies. Author summary: HIV infection results in progressive disease culminating in AIDS in most individuals if left untreated. A rare set of individuals, called natural controllers, however, can control the virus without treatment. Understanding what underlies such control may help devise strategies to elicit it in non-controllers. A challenge has been the limited understanding of the mechanistic role of CD8 T-cells. Here, using new mathematical modeling which enabled simultaneous analysis of in vivo and ex vivo longitudinal data from macaques infected with SIV, we identified the cumulative infection suppressive capacity of CD8 T-cells early in infection (4–6 weeks) as a measurable correlate of control in the chronic phase of the infection. This cumulative suppressive capacity was significantly higher in controllers than non-controllers, attributed by our model to superior CD8 T-cell recruitment rate and/or maximal killing rate in the controllers. Our study quantifies the role of CD8 T-cells in the natural control of SIV and has implications for interventions targeting long-term HIV remission. [ABSTRACT FROM AUTHOR]

CD8+ T cells are the workhorses executing adaptive anti-tumour response, and targets of various cancer immunotherapies. Latest advances have unearthed the sheer heterogeneity of CD8+ tumour infiltrating lymphocytes, and made it increasingly clear that the bulk of the endogenous and therapeutically induced tumour-suppressive momentum hinges on a particular selection of CD8+ T cells with advantageous attributes, namely the memory and stem-like exhausted subsets. A scrutiny of the contemporary perception of CD8+ T cells in cancer and the subgroups of interest along with the factors arbitrating their infiltration contextures, presented herein, may serve as the groundwork for future endeavours to probe further into the regulatory networks underlying their differentiation and migration, and optimise T cell-based immunotherapies accordingly. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusions Our objective was to evaluate the trajectory of immunology in patients with HIV with different baseline CD4 T‐cell count strata after antiretroviral therapy (ART) under long‐term viral suppression.This was a sub‐analysis focused on patients with virological suppression for at least 5 years after ART. Data were obtained from the Yunnan HIV cohort in China. Patients were categorized according to prespecified baseline CD4 T‐cell counts. The trajectories of CD4 T‐cell count, CD8 T‐cell count, and CD4/CD8 ratio changing over time were fitted using a B‐spline regression model. The Cox proportional hazards regression model was used to assess the association of baseline CD4 T‐cell count with the risk of both immunological responder (IR) and CD4/CD8 ratio normalization.A total of 2618 patients with a median follow‐up of 7.25 years (interquartile range [IQR] 5.92–8.75) were included. Over a period of 12 years, the mean CD4 T‐cell count remained above 500 cells/μL in all groups. The mean CD4/CD8 ratio was solely normalized in patients whose baseline CD4 T‐cell counts were above 350 cells/μL. Patients with higher baseline CD4 T‐cell counts showed higher risks of both IR and CD4/CD8 ratio normalization than those with the lowest (all p trend <0.001). A higher baseline CD4 T‐cell count predicted a shorter time for both IR and CD4/CD8 ratio normalization.Long‐term, sustained viral suppression may not be able to fully normalize immunological functions in patients with HIV. A high baseline CD4 T‐cell count benefits IR and CD4/CD8 ratio normalization. [ABSTRACT FROM AUTHOR]

CD80 is the best-known costimulatory molecule for effective T cell functions. Many different reports have summarized the role of CD80 in HSV-1 and its functions in maintaining adaptive immunity, which is the main player in causing herpes stromal keratitis (HSK). To determine the effects of absence or overexpression of CD80 in HSV-1 infection, we infected CD80-/- and WT mice with a recombinant HSV-1 expressing murine CD80 (HSV-CD80) in place of the latency associated transcript (LAT). Parental dLAT2903 virus lacking LAT was used as a control. After infection, critical components of infection like virus replication, eye disease, early cellular infiltrates into the corneas and trigeminal ganglia (TG), latency-reactivation in the infected mice were determined. Our findings reveal that the absence of CD80 in the CD80-/- mice infected with both viruses did not affect the viral titers in the mice eyes or eye disease, but it played a significant role in critical components of HSV-induced immunopathology. The WT mice infected with dLAT2903 virus had significantly higher levels of latency compared with the CD80-/- mice infected with dLAT2903 virus, while levels of latency as determined by gB DNA expression were similar between the WT and CD80-/- mice infected with HSV-CD80 virus. In contrast to the differences in the levels of latency between the infected groups, the absence of CD80 expression in the CD80-/- mice or its overexpression by HSV-CD80 virus did not have any effect on the time of reactivation. Furthermore, the absence of CD80 expression contributed to more inflammation in the CD80-/--infected mice. Overall, this study suggests that in the absence of CD80, inflammation increases, latency is reduced, but reactivation is not affected. Altogether, our study suggests that reduced latency correlated with reduced levels of inflammatory molecules and blocking or reducing expression of CD80 could be used to mitigate the immune responses, therefore controlling HSV-induced infection. [ABSTRACT FROM AUTHOR]

Our study included 41 patients fulfilling the Milan criteria preoperatively and aimed to identify individuals at high risk of post-resection HCC relapse, which occurred in 18 out of 41 patients (43.9%), retrospectively. We analyzed whole slide images of CD8 immunohistochemistry with automated segmentation of tissue classes and detection of CD8+ lymphocytes. The image analysis outputs were subsampled using a hexagonal grid-based method to assess spatial distribution of CD8+ lymphocytes with regards to the epithelial edges. The CD8+ lymphocyte density indicators, along with clinical, radiological, post-surgical and pathological variables, were tested to predict HCC relapse. Low standard deviation of CD8+ density along the tumor edge and R1 resection emerged as independent predictors of shorter recurrence-free survival (RFS). In particular, patients presenting with both adverse predictors exhibited 100% risk of relapse within 200 days. Our results highlight the potential utility of integrating CD8+ density variability and surgical margin to identify a high relapse-risk group among Milan criteria-fulfilling HCC patients. Validation in cohorts with core biopsy could provide CD8+ distribution data preoperatively and guide preoperative decisions, potentially prioritizing liver transplantation for patients at risk of incomplete resection (R1) and thereby improving overall treatment outcomes significantly. [ABSTRACT FROM AUTHOR]

Objective: The TGF‐β superfamily member activin, a dimer of the gene products of INHBA and/or INHBB, has been implicated in immune cell maturation and recruitment, but its immune impact within epithelial ovarian cancer (EOC) is not well characterized. We sought to explore differences in activin (INHBA/ Inhibin‐βA and INHBB/ Inhibin‐βB) between malignant and ovarian tissues at the RNA and protein level and assess the relationship between activin and immune cells in EOC. Methods: Publicly available RNA sequencing data were accessed from GEO (#GSE143897) with normalization and quantification performed via DESeq2. Immune gene expression profile was further explored within the TCGA‐OV cohort derived from The Cancer Genome Atlas (TCGA). Immunohistochemical analysis was performed to evaluate activin A and T‐cell markers CD8 and FoxP3 at the protein level. ELISA to activin‐A was used to assess levels in the ascites of advanced EOC patients. Kaplan–Meier curves were generated to visualize survival outcomes. Results: Gene expression levels of components of the activin signaling pathway were elevated within EOC when compared to a benign cohort, with differences in activin type I/II receptor gene profiles identified. Additionally, INHBA gene expression was linked to lymphocytic immune markers in EOC samples. Immunohistochemistry analysis revealed a positive correlation of CD8 and FOXP3 staining with activin A at the protein level in both primary and metastatic epithelial ovarian cancer samples. Furthermore, Activin‐A (inhibin‐βA) is significantly elevated in EOC patient ascites. Conclusion: INHBA expression is elevated within EOC, correlating with worse survival, with activin protein levels correlating with specific immune infiltration. Our findings suggest that activin‐A may play a role in suppressing anti‐tumor immunity in EOC, highlighting its potential as a therapeutic target. [ABSTRACT FROM AUTHOR]

In recent years, Raman spectroscopy has garnered growing interest in the field of biomedical research. It offers a non-invasive and label-free approach to defining the molecular fingerprint of immune cells. We utilized Raman spectroscopy on optically trapped immune cells to investigate their molecular compositions. While numerous immune cell types have been studied in the past, the characterization of living human CD3/CD28-stimulated T cell subsets remains incomplete. In this study, we demonstrate the capability of Raman spectroscopy to readily distinguish between naïve and stimulated CD4 and CD8 cells. Additionally, we compared these cells with monocytes and discovered remarkable similarities between stimulated T cells and monocytes. This paper contributes to expanding our knowledge of Raman spectroscopy of immune cells and serves as a launching point for future clinical applications. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV) infects CD4+ cells and causes progressive immune function failure, and CD8+ cells lyse infected CD4+ cell via recognising peptide presented by human leukocyte antigens (HLA). Variations in HLA allele lead to observed different HIV infection outcomes. Within-host HIV dynamics involves virus replication within infected cells and lysing of infected cells by CD8+ cells, but how variations in HLA alleles determine different infection outcomes was far from clear. Here, we used mathematical modelling and parameter inference with a new analysis of published virus inhibition assay data to estimate CD8+ cell lysing efficiency, and found that lysing efficiency fall in the gap between low bound (0.1–0.2 day−1 (Elemans et al. in PLoS Comput Biol 8(2):e1002381, 2012)) and upper boundary (6.5–8.4 day−1 (Wick et al. in J Virol 79(21):13579–13586, 2005)). Our outcomes indicate that both lysing efficiency and viral inoculum size jointly determine observed different infection outcomes. Low lysing rate associated with non-protective HLA alleles leads to monostable viral kinetic to high viral titre and oscillatory viral kinetics. High lysing rate associated with protective HLA alleles leads monostable viral kinetic to low viral titre and bistable viral kinetics; at a specific interval of CD8+ cell counts, small viral inoculum sizes are inhibited but not large viral inoculum sizes remain infectious. Further, with CD8+ cell recruitment, HIV kinetics always exhibit oscillatory kinetics, but lysing rate is negatively correlated with range of CD8+ cell count. Our finding highlights role of HLA allele determining different infection outcomes, thereby providing a potential mechanistic explanation for observed good and bad HIV infection outcomes induced by protective HLA allele. [ABSTRACT FROM AUTHOR]

Members of the Protein kinases D (PKD) family are described as regulators of T cell responses. From the two T cell‐expressed isoforms PKD2 and PKD3, so far mainly the former was thoroughly investigated and is well understood. Recently, we have investigated also PKD3 using conventional as well as conditional T cell‐specific knockout models. These studies suggested PKD3 to be a T cell‐extrinsic regulator of the cells' fate. However, these former model systems did not take into account possible redundancies with the highly homologous PKD2. To overcome this issue and thus properly unravel PKD3's T cell‐intrinsic functions, here we additionally used a mouse model overexpressing a constitutively active isoform of PKD3 specifically in the T cell compartment. These transgenic mice showed a slightly higher proportion of central memory T cells in secondary lymphoid organs and blood. This effect could not be explained via differences upon polyclonal stimulation in vitro, however, may be connected to the observed developmental aberrances in the CD8 single positive compartment during thymic development. Lastly, the observed alterations in the CD8+ T cell compartment did not impact proper immune response upon immunization with ovalbumin or in a subcutaneous tumour model suggesting only a small to absent biological relevance. Taking together the knowledge of all our published studies on PKD3 in the T cell compartment, we now conclude that T cell‐intrinsic PKD3 is a fine‐tuner of central memory T cell as well as CD8 single positive thymocyte development. [ABSTRACT FROM AUTHOR]

Targeted therapy and immunotherapy has brought new hope to patients with lung adenocarcinoma (LUAD) with their applications. However, the prognosis of LUAD patients is still unpromising. It is particularly important to find the biomarkers that can predict the prognosis of LUAD. In our previous study, we found that patients with high expression of LINC02390 had a better prognosis. The clinical significance of LINC02390 and its potential target genes, CLECL1 and CD69, in the prognosis of LUAD and its role in the immune microenvironment were explored. Through the survival analysis, LINC02390 and its potential target genes, CLECL1 and CD69, were identified as good prognostic factors for LUAD. According to GO and KEGG analyses, LINC02390-related genes were identified potentially involved in immune-related signaling pathways. Gene mutations and their relationship with immune cell infiltration were verified through the online cbioportal and TIMER database. CD69 was found to positively associate with CD8 + T cells and CLECL1 was also positively associated with CD4 + T cells. A high expression of CD69 in CD8 + T cells was identified through the single-cell sequencing dataset GSE111894. Finally, CLECL1 and CD69 were lowly expressed in clinical tissue samples with LUAD by immunohistochemical staining. LINC02390 and its possible target genes, CLECL1 and CD69, may be potential targets for the immunotherapy in LUAD patients. [ABSTRACT FROM AUTHOR]

Objective • This study aimed to evaluate the impact of cinobufacini capsules in patients who underwent total thyroidectomy for differentiated thyroid cancer (DTC). Methods • A prospective cohort study was conducted, and a total of 120 DTC patients were selected. The patients were divided into two groups: a control group receiving standard postoperative treatment (n = 60) and a cinobufacini group receiving cinobufacini capsules in addition to standard treatment (n = 60). Various assessments were conducted, including pain evaluation, lymphocyte subset measurement, as well as the quantification of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), free sulfhydryl (-SH) levels, and lipid hydroperoxides (LOOH) in serum. Results • Both groups experienced reduced pain levels after one month of treatment, with the cinobufacini group demonstrating a more significant reduction. In comparison to the control group, one month of cinobufacini treatment resulted in substantial increases in NK cell activity, percentages of NK cells, activated NK cells, and CD8+ T-cells. It also led to the mitigation of oxidative stress and inflammation response. Conclusions • These findings indicate that cinobufacini may serve as an adjunctive therapy for DTC patients, offering benefits in pain management, immune modulation, and reducing inflammation and oxidative stress after surgery. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the expression of GPR56 in the T cells of early-stage lung adenocarcinoma (LUAD) patients and clarify its diagnostic significance. Methods: Blood samples were collected from 32 patients with stage IA LUAD and 31 healthy controls. GPR56 and perforin were analysed in circulating T-cell subsets by flow cytometry. In addition, a correlation between perforin and GPR56 expression was detected. Changes in GPR56+ cells in early LUAD patients were analysed, and the diagnostic significance of GPR56+ T cells for early LUAD was studied by receiver operating characteristic (ROC) curve analysis. Results: The expression of GPR56 in CD8+ T cells from early-stage LUAD patients was significantly greater than that in CD4+ T cells. The percentage of perforin-positive GPR56+ cells in early-stage LUAD patients was high. GPR56 levels in the T cells of LUAD patients were significantly lower than those in healthy controls. ROC analysis revealed that the area under the curve for the percentage of GPR56-positive CD8+ TEMRA cells to distinguish early-stage LUAD patients from healthy individuals- reached 0.7978. Conclusion: The decreased expression of GPR56 in the peripheral blood of early-stage LUAD patients correlated with perforin levels, reflecting compromised antitumor immunity and aiding early-stage LUAD screening. [ABSTRACT FROM AUTHOR]

Transplantation of human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs) has emerged as a promising therapy to treat end-stage heart failure. However, the immunogenicity of hiPS-CMs in transplanted patients has not been fully elucidated. Thus, in vivo models are required to estimate immune responses against hiPS-CMs in transplant recipients. We transferred human peripheral blood mononuclear cells (hPBMCs) into NOD/Shi- scid IL-2rg null (NOG) MHC class I/II double knockout (NOG-ΔMHC) mice, which were reported to accept hPBMCs without xenogeneic-graft- versus -host disease (xeno-GVHD). Then, hiPS-CM sheets generated from the hiPS cell line 201B7 harboring a luciferase transgene were transplanted into the subcutaneous space of NOG-ΔMHC mice. Graft survival was monitored by bioluminescent images using a Xenogen In Vivo Imaging System. The human immune cells were engrafted for more than 3 months in NOG-ΔMHC mice without lethal xeno-GVHD. The hiPS-CMs expressed a moderate level of human leukocyte antigen (HLA)-class I, but not HLA-class II, molecules even after interferon-gamma (IFN-γ) stimulation. Consistently, the allogenic IFN-γ-treated hiPS-CMs induced weak CD8+ but not CD4+ T cell responses in vitro. hiPS-CM sheets disappeared approximately 17 to 24 days after transplantation in hPBMC-transferred NOG-ΔMHC mice, and CD8+ T cell depletion significantly prolonged graft survival, similar to what was observed following tacrolimus treatment. hiPS-CMs are less immunogenic in vitro but induce sufficient CD8+ T cell-mediated immune responses for graft rejection in vivo. [ABSTRACT FROM AUTHOR]

Despite the numerous studies on the clinical aspects of early-onset preeclampsia, our understanding of the immunological consequences of inadequate placenta development remains incomplete. The Th1-predominance characteristic of early-onset preeclampsia significantly impacts maternal immunotolerance, and the role of immune checkpoint molecules in these mechanisms is yet to be fully elucidated. Our study aims to fill these crucial knowledge gaps. A total of 34 pregnant women diagnosed with early-onset preeclampsia and 34 healthy pregnant women were enrolled in this study. A mononuclear cell fragment from the venous blood was separated and frozen. The CD8+ and CD8− NK cell subpopulations were identified and compared to their immune checkpoint molecule expressions using multicolor flow cytometry. The serum CD226 levels were measured by ELISA. Based on our measures, the frequency of the CD8− subpopulation was significantly higher than that of the CD8+ counterpart in both the NKdim and NKbright subsets. Significantly lower CD226 surface expressions were detected in the preeclamptic group compared to healthy women in all the investigated subpopulations. However, while no difference was observed in the level of the soluble CD226 molecule between the two groups, the CD112 and CD155 surface expressions were significantly different. Our study's findings underscore the significant role of the CD8+ and CD8− NK subpopulations in the Th1-dominated immune environment. This deepens our understanding of early-onset preeclampsia and suggests that each subpopulation could contribute to the compensation mechanisms and the restoration of the immunological balance in this condition, a crucial step toward developing effective interventions. [ABSTRACT FROM AUTHOR]

The incidence of breast cancer (BC) continues to rise steadily, posing a significant burden on the public health systems of various countries worldwide. As a member of the tumor microenvironment (TME), CD8+ T cells inhibit cancer progression through their protective role. This study aims to investigate the role of CD8+ T cell-related genes (CTRGs) in breast cancer patients. Methods: We assessed the abundance of CD8+ T cells in the TCGA and METABRIC datasets and obtained CTRGs through WGCNA. Subsequently, a prognostic signature (CTR score) was constructed from CTRGs screened by seven machine learning algorithms, and the relationship between the CTR score and TME, immunotherapy, and drug sensitivity was analyzed. Additionally, CTRGs' expression in different cells within TME was identified through single-cell analysis and spatial transcriptomics. Finally, the expression of CTRGs in clinical tissues was verified via RT-PCR. Results: The CD8+ T cell-related prognostic signature consists of two CTRGs. In the TCGA and METABRIC datasets, the CTR score appeared to be negatively linked to the abundance of CD8+ T cells, and BC patients with higher risk score show a worse prognosis. The low CTR score group exhibits higher immune infiltration levels, closely associated with inhibiting the tumor microenvironment. Compared with the high CTR score group, the low CTR score group shows better responses to chemotherapy and immune checkpoint therapy. Single-cell analysis and spatial transcriptomics reveal the heterogeneity of two CTRGs in different cells. Compared with the adjacent tissues, CD163L1 and KLRB1 mRNA are downregulated in tumor tissues. Conclusions: This study establishes a robust CD8+ T cell-related prognostic signature, providing new insights for predicting the clinical outcomes and treatment responses of breast cancer patients. [ABSTRACT FROM AUTHOR]

Antigen-specific cytotoxic CD8 T cells are extremely effective in controlling tumor growth and have been the focus of immunotherapy approaches. We leverage in silico tools to investigate whether the occurrence of mutations in proteins previously described as immunogenic and highly expressed by glioblastoma multiforme (GBM), such as Epidermal Growth Factor Receptor (EGFR), Isocitrate Dehydrogenase 1 (IDH1), Phosphatase and Tensin homolog (PTEN) and Tumor Protein 53 (TP53), may be contributing to the differential presentation of immunogenic epitopes. We recovered Class I MHC binding information from wild-type and mutated proteins using the Immune Epitope Database (IEDB). After that, we built peptide-MHC (pMHC-I) models in HLA-arena, followed by hierarchical clustering analysis based on electrostatic surface features from each complex. We identified point mutations that are determinants for the presentation of a set of peptides from TP53 protein. We point to structural features in the pMHC-I complexes of wild-type and mutated peptides, which may play a role in the recognition of CD8 T cells. To further explore these features, we performed 100 ns molecular dynamics simulations for the peptide pairs (wt/mut) selected. In pursuit of novel therapeutic targets for GBM treatment, we selected peptides where our predictive results indicated that mutations would not disrupt epitope presentation, thereby maintaining a specific CD8 T cell immune response. These peptides hold potential for future GBM interventions, including peptide-based or mRNA vaccine development applications. [ABSTRACT FROM AUTHOR]

Background: T cells play a pivotal role in chemotherapy-triggered anti-tumor effects. Emerging evidence underscores the link between impaired anti-tumor immune responses and resistance to paclitaxel therapy in triple-negative breast cancer (TNBC). Tumor-related endothelial cells (ECs) have potential immunoregulatory activity. However, how ECs regulate T cell activity during TNBC chemotherapy remains poorly understood. Methods: Single-cell analysis of ECs in patients with TNBC receiving paclitaxel therapy was performed using an accessible single-cell RNA sequencing (scRNA-seq) dataset to identify key EC subtypes and their immune characteristics. An integrated analysis of a tumor-bearing mouse model, immunofluorescence, and a spatial transcriptome dataset revealed the spatial relationship between ECs, especially Tumor necrosis factor receptor (TNFR) 2+ ECs, and CD8+ T cells. RNA sequencing, CD8+ T cell proliferation assays, flow cytometry, and bioinformatic analyses were performed to explore the immunosuppressive function of TNFR2 in ECs. The downstream metabolic mechanism of TNFR2 was further investigated using RNA sequencing, cellular glycolysis assays, and western blotting. Results: In this study, we identified an immunoregulatory EC subtype, characterized by enhanced TNFR2 expression in non-responders. By a mouse model of TNBC, we revealed a dynamic reduction in the proportion of the CD8+ T cell-contacting tumor vessels that could co-localize spatially with CD8+ T cells during chemotherapy and an increased expression of TNFR2 by ECs. TNFR2 suppresses glycolytic activity in ECs by activating NF-κB signaling in vitro. Tuning endothelial glycolysis enhances programmed death-ligand (PD-L) 1-dependent inhibitory capacity, thereby inducing CD8+ T cell suppression. In addition, TNFR2+ ECs showed a greater spatial affinity for exhausted CD8+ T cells than for non-exhausted CD8+ T cells. TNFR2 blockade restores impaired anti-tumor immunity in vivo, leading to the loss of PD-L1 expression by ECs and enhancement of CD8+ T cell infiltration into the tumors. Conclusions: These findings reveal the suppression of CD8+ T cells by ECs in chemoresistance and indicate the critical role of TNFR2 in driving the immunosuppressive capacity of ECs via tuning glycolysis. Targeting endothelial TNFR2 may serve as a potent strategy for treating TNBC with paclitaxel. [ABSTRACT FROM AUTHOR]

Targeting intracellular inhibiting proteins has been revealed to be a promising strategy to improve CD8+ T cell anti-tumor efficacy. Here, we are focusing on intracellular inhibiting proteins specific to TCR signaling: DOK1 and DOK2 expressed in T cells. We hypothesized that depletion of intracellular inhibition checkpoint DOK1 and DOK2 could improve CD8+ T-cell based cancer therapies. To evaluate the role of DOK1 and DOK2 depletion in physiology and effector function of CD8+ T lymphocytes and in cancer progression, we established a transgenic T cell receptor mouse model specific to melanoma antigen hgp100 (pmel-1 TCR Tg) in WT and Dok1/Dok2 DKO (double KO) mice. We showed that both DOK1 and DOK2 depletion in CD8+ T cells after an in vitro pre-stimulation induced a higher percentage of effector memory T cells as well as an up regulation of TCR signaling cascade- induced by CD3 mAbs, including the increased levels of pAKT and pERK, two major phosphoproteins involved in T cell functions. Interestingly, this improved TCR signaling was not observed in naïve CD8+ T cells. Despite this enhanced TCR signaling essentially shown upon stimulation via CD3 mAbs, pre-stimulated Dok1/Dok2 DKO CD8+ T cells did not show any increase in their activation or cytotoxic capacities against melanoma cell line expressing hgp100 in vitro. Altogether we demonstrate here a novel aspect of the negative regulation by DOK1 and DOK2 proteins in CD8+ T cells. Indeed, our results allow us to conclude that DOK1 and DOK2 have an inhibitory role following long term T cell stimulations. [ABSTRACT FROM AUTHOR]

Background: Infants with frequent viral and bacterial respiratory infections exhibit compromised immunity to routine immunizations. They are also more likely to develop chronic respiratory diseases in later childhood. This study investigated the feasibility of epigenetic profiling to reveal endotype-specific molecular pathways with potential for early identification and immuno-modulation. Peripheral blood mononuclear cells from respiratory infection allergy/asthma-prone (IAP) infants and non-infection allergy/asthma prone (NIAP) were retrospectively selected for genome-wide DNA methylation and single nucleotide polymorphism analysis. The IAP infants were enriched for the low vaccine responsiveness (LVR) phenotype (Fisher's exact p-value = 0.02). Results: An endotype signature of 813 differentially methylated regions (DMRs) comprising 238 lead CpG associations (FDR < 0.05) emerged, implicating pathways related to asthma, mucin production, antigen presentation and inflammasome activation. Allelic variation explained only a minor portion of this signature. Stimulation of mononuclear cells with monophosphoryl lipid A (MPL), a TLR agonist, partially reversed this signature at a subset of CpGs, suggesting the potential for epigenetic remodeling. Conclusions: This proof-of-concept study establishes a foundation for precision endotyping of IAP children and highlights the potential for immune modulation strategies using adjuvants for future investigation. [ABSTRACT FROM AUTHOR]

Acute lung allograft dysfunction (ALAD) is an imprecise syndrome denoting concern for the onset of chronic lung allograft dysfunction (CLAD). Mechanistic biomarkers are needed that stratify risk of ALAD progression to CLAD. We hypothesized that single cell investigation of bronchoalveolar lavage (BAL) cells at the time of ALAD would identify immune cells linked to progressive graft dysfunction. We prospectively collected BAL from consenting lung transplant recipients for single cell RNA sequencing. ALAD was defined by a ≥10% decrease in FEV 1 not caused by infection or acute rejection and samples were matched to BAL from recipients with stable lung function. We examined cell compositional and transcriptional differences across control, ALAD with decline, and ALAD with recovery groups. We also assessed cell-cell communication. BAL was assessed for 17 ALAD cases with subsequent decline (ALAD declined), 13 ALAD cases that resolved (ALAD recovered), and 15 cases with stable lung function. We observed broad differences in frequencies of the 26 unique cell populations across groups (p = 0.02). A CD8 T cell (p = 0.04) and a macrophage cluster (p = 0.01) best identified ALAD declined from the ALAD recovered and stable groups. This macrophage cluster was distinguished by an anti-inflammatory signature and the CD8 T cell cluster resembled a Tissue Resident Memory subset. Anti-inflammatory macrophages signaled to activated CD8 T cells via class I HLA, fibronectin, and galectin pathways (p < 0.05 for each). Recipients with discordance between these cells had a nearly 5-fold increased risk of severe graft dysfunction or death (HR 4.6, 95% CI 1.1–19.2, adjusted p = 0.03). We validated these key findings in 2 public lung transplant genomic datasets. BAL anti-inflammatory macrophages may protect against CLAD by suppressing CD8 T cells. These populations merit functional and longitudinal assessment in additional cohorts. [ABSTRACT FROM AUTHOR]

Staphylococcal toxic shock syndrome (STSS) is a rare, yet potentially fatal disease caused by Staphylococcus aureus (S. aureus) enterotoxins, known as superantigens, which trigger an intense immune response. Our previous study demonstrated the protective effect of tofacitinib against murine toxin-induced shock and a beneficial effect against S. aureus sepsis. In the current study, we examined the effects of tofacitinib on T-cell response in peripheral blood using a mouse model of enterotoxin-induced shock. Our data revealed that tofacitinib suppresses the activation of both CD4+ and CD8+ T cells in peripheral blood. Furthermore, both gene and protein levels of Th1 cytokines were downregulated by tofacitinib treatment in mice with enterotoxin-induced shock. Importantly, we demonstrated that CD4+ cells, but not CD8+ cells, are pathogenic in mice with enterotoxin-induced shock. In conclusion, our findings suggest that tofacitinib treatment suppresses CD4+ T-cell activation and Th1 response, thereby aiding in protection against staphylococcal toxic shock in mice. This insight may guide the future development of novel therapies for STSS. [ABSTRACT FROM AUTHOR]

Background: Study of expression of lymphocyte subsets could help to understand the pathophysiology of COVID-19 infection, development of novel treatment protocols and reducing rate of mortality among COVID-19 infected patients. The aim of this work was to correlate expression of lymphocyte subsets with the inflammatory markers and clinical status of patients with COVID-19 infection. Methods: This prospective study was performed at Zagazig University Isolation Hospitals and clinical pathology department, Zagazig, Egypt on 80 persons who were enrolled in this study; 40 COVID-19 patients with pneumonia made up group I, and the following individuals made up group II: 40 COVID-19 patients without pneumonia. Immunophenotyping of CD4 CD8 were measured by Flow Cytometry in both groups. Results: Patients had a considerable drop in CD4 CD8 levels with pneumonia than those without pneumonia Conclusions: Low levels of CD4 CD8 in COVID-19 patients are associated with a higher risk of pneumonia. [ABSTRACT FROM AUTHOR]

CD8 + T cells exert a critical role in eliminating cancers and chronic infections, and can provide long-term protective immunity. However, under the exposure of persistent antigen, CD8 + T cells can differentiate into terminally exhausted CD8 + T cells and lose the ability of immune surveillance and disease clearance. New insights into the molecular mechanisms of T-cell exhaustion suggest that it is a potential way to improve the efficacy of immunotherapy by restoring the function of exhausted CD8 + T cells. Transforming growth factor-β (TGF-β) is an important executor of immune homeostasis and tolerance, inhibiting the expansion and function of many components of the immune system. Recent studies have shown that TGF-β is one of the drivers for the development of exhausted CD8 + T cells. In this review, we summarized the role and mechanisms of TGF-β in the formation of exhausted CD8 + T cells and discussed ways to target those to ultimately enhance the efficacy of immunotherapy. [ABSTRACT FROM AUTHOR]

Peripheral blood CD8+ T lymphocytes play a crucial role in cell-mediated immunity and tumor-related immune responses in breast cancer. In this study, label-free quantification analysis and gene set enrichment analysis (GSEA) of CD8+ T lymphocytes in the peripheral blood of benign patients and patients with different breast cancer (BC) subtypes, i.e., luminal A, luminal B, and triple-negative breast cancer (TNBC), were performed using nano-UHPLC and Orbitrap mass spectrometry. Differential protein expression in CD8+ T lymphocytes revealed significant downregulation (log2 FC ≥ 0.38 or ≤−0.38, adj. p < 0.05), particularly in proteins involved in cytotoxicity, cytolysis, and proteolysis, such as granzymes (GZMs) and perforin 1 (PRF1). This downregulation was observed in the benign group (GZMH, GZMM, and PRF1) and luminal B (GZMA, GZMH) subtypes, whereas granzyme K (GZMK) was upregulated in TNBC in comparison to healthy controls. The RNA degradation pathway was significantly downregulated (p < 0.05, normalized enrichment score (NES) from −1.47 to −1.80) across all BC subtypes, suggesting a potential mechanism for regulating gene expression during T cell activation. Also, the Sm-like proteins (LSM2, LSM3, and LSM5) were significantly downregulated in the RNA degradation pathway. Proteomic analysis of CD8+ T lymphocytes in peripheral blood across different breast cancer subtypes provides a comprehensive view of the molecular mechanisms of the systemic immune response that can significantly contribute to advancements in the diagnosis, treatment, and prognosis of this disease. [ABSTRACT FROM AUTHOR]

Chronic Toxoplasma gondii infection induces brain-resident CD8+ T cells (bTr), but the protective functions and differentiation cues of these cells remain undefined. Here, we used a mouse model of latent infection by T. gondii leading to effective CD8+ T cell-mediated parasite control. Thanks to antibody depletion approaches, we found that peripheral circulating CD8+ T cells are dispensable for brain parasite control during chronic stage, indicating that CD8+ bTr are able to prevent brain parasite reactivation. We observed that the retention markers CD69, CD49a, and CD103 are sequentially acquired by brain parasite-specific CD8+ T cells throughout infection and that a majority of CD69/CD49a/CD103 triple-positive (TP) CD8+ T cells also express Hobit, a transcription factor associated with tissue residency. This TP subset develops in a CD4+ T cell-dependent manner and is associated with effective parasite control during chronic stage. Conditional invalidation of Transporter associated with Antigen Processing (TAP)-mediated major histocompatibility complex (MHC) class I presentation showed that presentation of parasite antigens by glutamatergic neurons and microglia regulates the differentiation of CD8+ bTr into TP cells. Single-cell transcriptomic analyses revealed that resistance to encephalitis is associated with the expansion of stem-like subsets of CD8+ bTr. In summary, parasite-specific brain-resident CD8+ T cells are a functionally heterogeneous compartment which autonomously ensure parasite control during T. gondii latent infection and which differentiation is shaped by neuronal and microglial MHC I presentation. A more detailed understanding of local T cell-mediated immune surveillance of this common parasite is needed for harnessing brain-resident CD8+ T cells in order to enhance control of chronic brain infections. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) and glioblastoma (GBM) are CNS diseases in whose development and progression immune privilege is intimately important, but in a relatively opposite manner. Maintenance and strengthening of immune privilege have been shown to be an important mechanism in glioblastoma immune evasion, while the breakdown of immune privilege leads to MS initiation and exacerbation. We hypothesize that molecular signaling pathways can be oppositely regulated in peripheral blood CD8+ T cells of MS and glioblastoma patients at a transcriptional level. We analyzed publicly available data of the peripheral blood CD8+ T cell MS vs. control (MSvsCTRL) and GBM vs. control (GBMvsCTRL) differentially expressed gene (DEG) contrasts with Qiagen's Ingenuity pathway analysis software (IPA). We have identified sphingolipid signaling pathway which was significantly downregulated in the GBMvsCTRL and upregulated in the MSvsCTRL. As the pathway is important for the CD8+ T lymphocytes CNS infiltration, this result is in line with our previously stated hypothesis. Comparing publicly available lists of differentially expressed serum exosomal miRNAs from MSvsCTRL and GBMvsCTRL contrasts, we have identified that hsa-miR-182-5p has the greatest potential effect on sphingolipid signaling regarding the number of regulated DEGs in the GBMvsCTRL contrast, while not being able to find any relevant potential sphingolipid signaling target transcripts in the MSvsCTRL contrast. We conclude that the sphingolipid signaling pathway is a top oppositely regulated pathway in peripheral blood CD8+ T cells from GBM and MS, and might be crucial for the differences in CNS immune privilege maintenance of investigated diseases, but further experimental research is necessary. [ABSTRACT FROM AUTHOR]

Background: Despite the success of antiretroviral therapy (ART), people living with HIV (PLWH) suffer from a high burden of pulmonary diseases, even after accounting for their smoking status. Cytotoxic CD8 T-cells are likely implicated in this phenomenon and may act as a double-edged sword. While being essential in viral infection control, their hyperactivation can also contribute to lung mucosal tissue damage. The effects of HIV and smoking on pulmonary mucosal CD8 T-cell dynamics has been a neglected area of research, which we address herein. Methods: Bronchoalveolar lavage (BAL) fluid were obtained from ART-treated PLWH (median duration of supressed viral load: 9 years; smokers: n = 14; non-smokers: n = 21) and HIV-uninfected controls (smokers: n = 11; non-smokers: n = 20) without any respiratory symptoms or active infection. Lymphocytes were isolated and CD8 T-cell subsets and homing markers were characterized by multiparametric flow cytometry. Results: Both smoking and HIV infection were independently associated with a significant increase in frequencies of total pulmonary mucosal CD8 T-cell. BAL CD8 T-cells were primarily CD69 + expressing CD103 and/or CD49a, at least one of the two granzymes (GzmA/GzmB), and little Perforin. Higher expression levels of CD103, CD69, and GzmB were observed in smokers versus non-smokers. The ex vivo phenotype of GzmA + and GzmB + cells revealed increased expression of CD103 and CXCR6 in smokers, while PLWH displayed elevated levels of CX3CR1 compared to controls. Conclusion: Smoking and HIV could promote cytotoxic CD8 T-cell retention in small airways through different mechanisms. Smoking likely increases recruitment and retention of GzmB + CD8 Trm via CXCR6 and CD103. Heightened CX3CR1 expression could be associated with CD8 non-Trm recruitment from the periphery in PLWH. [ABSTRACT FROM AUTHOR]

Cancer immunotherapy is a pillar of clinical oncology but only achieves long-term remissions in a minority of cases. In this issue, van Elsas et al. show that effective immunotherapy requires a series of processes orchestrated by CD8+ T cells that result in the recruitment and local activation of M1-like macrophages. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) is an industrial solvent and widespread environmental contaminant associated with CD4+ T-cell activation and autoimmune disease. Prior studies showed that exposure to TCE in the drinking water of autoimmune-prone mice expanded effector/memory CD4+ T cells with an interferon-γ (IFN-γ)-secreting Th1-like phenotype. However, very little is known how TCE exposure skews CD4+ T cells towards this pro-inflammatory Th1 subset. As observed previously, TCE exposure was associated with hypermethylation of regions of the genome related to transcriptional repression in purified effector/memory CD4 T cells. We hypothesized that TCE modulates transcriptional and/or epigenetic programming of CD4+ T cells as they differentiate from a naive to effector phenotype. In the current study, purified naive CD4 T cells from both male and female autoimmune-prone MRL/MpJ mice were activated ex vivo and polarized towards a Th1 subset for 4 days in the presence or absence of the oxidative metabolite of TCE, trichloroacetaldehyde hydrate (TCAH) in vitro. An RNA-seq assessment and reduced representation bisulfite sequencing for DNA methylation were conducted on Th1 cells or activated, non-polarized cells. The results demonstrated TCAH's ability to regulate key genes involved in the immune response and autoimmunity, including Ifng, by altering the level of DNA methylation at the gene promoter. Intriguing sex differences were observed and for the most part, the effects were more robust in females compared to males. In conclusion, TCE via TCAH epigenetically regulates gene expression in CD4+ T cells. These results may have implications for mechanistic understanding or future therapeutics for autoimmunity. [ABSTRACT FROM AUTHOR]

Objectives: Gout is characterized by hyperuricemia and recurrent inflammatory episodes caused by intra-articular crystal deposition of monosodium urate (MSU). There is a clear relationship between gout and metabolic syndrome. Recent evidence indicates that perforin plays a role in regulating glucose homeostasis and provides protection in diet-induced non-alcoholic steatohepatitis models. However, the impact of perforin on immune inflammation in gout remains unclear. Methods: We induced acute gout models in both wild-type (WT) mice and Prf1null mice by administering intra-articular injections of MSU crystals. We compared the ankle joint swelling and the histological score between the two groups. Furthermore, we investigated underlying mechanisms through in vitro co-culture experiments involving CD8 T cells and macrophages. Results: In this study, Prf1null mice showed significantly more pronounced ankle swelling with increased inflammatory cell infiltrations compared with WT mice 24 h after local MSU injection. Moreover, MSU-induced Prf1null mice exhibited increased accumulation of CD8 T cells but not NK cells. Perforin-deficient CD8 T cells displayed reduced cytotoxicity towards bone marrow–derived M0 and M1 macrophages and promoted TNF-α secretion from macrophage. Conclusions: Perforin from CD8 T cells limits joint inflammation in mice with acute gout by downregulating macrophage-mediated inflammation. Key Points • Perforin deficiency increased swelling in the ankle joints of mice upon MSU injection. • Perforin deficiency is associated with increased immune cell recruitment and severe joint damage in gout. • Perforin regulated CD8 T cell accumulation in gout and promoted CD8 T cell cytotoxicity towards M0 and M1 macrophages. • CD8 T cell-derived perforin regulated pro-inflammatory cytokine secretion of macrophage. [ABSTRACT FROM AUTHOR]

Background and Aim: Staphylococcus aureus, with its diverse virulence factors and immune response evasion mechanisms, presents a formidable challenge as an opportunistic pathogen. Developing an effective vaccine against S. aureus has proven elusive despite extensive efforts. Autologous Staphylococcus lysate (ASL) treatment has proven effective in triggering an immune response against bovine mastitis. Peptides that stimulate the immune response can be the subject of further research. The study aimed to use immunoinformatics tools to identify epitopes on S. aureus surface and secretory proteins that can bind to major histocompatibility complex class I (MHC I) and CD8+ T-cells. This method aids in discovering prospective vaccine candidates and elucidating the rationale behind ASL therapy's efficacy. Materials and Methods: Proteins were identified using both literature search and the National Center for Biotechnology Information search engine Entrez. Self and non-self peptides, allergenicity predictions, epitope locations, and physicochemical characteristics were determined using sequence alignment, AllerTOP, SVMTriP, and Protein-Sol tools. Hex was employed for simulating the docking interactions between S. aureus proteins and the MHC I + CD8+ T-cells complex. The binding sites of S. aureus proteins were assessed using Computer Atlas of Surface Topography of Proteins (CASTp) while docked with MHC I and CD8+ T-cells. Results: Nine potential S. aureus peptides and their corresponding epitopes were identified in this study, stimulating cytotoxic T-cell mediated immunity. The peptides were analyzed for similarity with self-antigens and allergenicity. 1d20, 2noj, 1n67, 1nu7, 1amx, and 2b71, non-self and stable, are potential elicitors of the cytotoxic T-cell response. The energy values from docking simulations of peptide-MHC I complexes with the CD8+ and T-cell receptor (TCR) indicate the stability and strength of the formed complexes. These peptides - 2noj, 1d20, 1n67, 2b71, 1nu7, 1yn3, 1amx, 2gi9, and 1edk - demonstrated robust MHC I binding, as evidenced by their low binding energies. Peptide 2gi9 exhibited the lowest energy value, followed by 2noj, 1nu7, 1n67, and 1d20, when docked with MHC I and CD8 + TCR, suggesting a highly stable complex. CASTp analysis indicated substantial binding pockets in the docked complexes, with peptide 1d20 showing the highest values for area and volume, suggesting its potential as an effective elicitor of immunological responses. These peptides - 2noj, 2gi9, 1d20, and 1n67 - stand out for vaccine development and T-cell activation against S. aureus. Conclusion: This study sheds light on the design and development of S. aureus vaccines, highlighting the significance of employing computational methods in conjunction with experimental verification. The significance of T-cell responses in combating S. aureus infections is emphasized by this study. More experiments are needed to confirm the effectiveness of these vaccine candidates and discover their possible medical uses. [ABSTRACT FROM AUTHOR]

Background: T cell stress response state (TSTR), as a novel immune concept previous studies have proposed, has not yet been explored in prostate cancer (PC). As a type of cellular efflux, exosomes play important roles in the occurrence and development of PC. Method: Here, we conducted a combined analysis on extracellular vesicle related genes (EVRGs) in PC using data from single-cell RNA (scRNA), spatial transcriptome (ST), and bulk RNA sequencing. Result: Preliminary findings have revealed that heat shock protein family H (Hsp110) member 1 (HSPH1) possesses two identities, one being EVRGs and the other being a member of the heat shock protein family involved in TSTR, which may promote the differentiation of conventional T cells towards Th1 or Th2 cells through the pathway of IL2-MYC-IL2RA, thereby promoting the increase of CD8 + T cells in the tumor area, especially in the invasive zone, and inhibiting the invasion of PCs. We also notice the negative response of HSPH1 + CD8 + T cell related genes in immune checkpoint blockade (ICB). Western blot (WB) and droplet digital Polymerase Chain Reaction (ddPCR) demonstrated that the mRNA and protein levels of HSPH1 in EVs of PCs were significantly higher than those in adjacent tissues. Conclusion: Results above indicate the potential of HSPH1 as a critical therapeutic target in PC. [ABSTRACT FROM AUTHOR]

CD8 downregulation is an overlooked component of self-reactive CD8+ T cell tolerance. CD8 downregulation is accompanied by T cell inhibition at the signaling and transcriptional levels. Loss of CD8 expression impairs the capacity of T cells to engage peptide-major histocompatibility complex complexes. CD8 downregulation may be a temporary event, as cells may regain CD8 expression and effector function. CD8 downregulation in mammals may be a part of a multilayered mechanism that inactivates self-reactive CD8+ T cells. Loss of CD8 may impair their capacity to engage target cells, while other simultaneous changes curb their activation and effector functions. Understanding this process represents a central element in our interpretation of CD8+ T cell physiology and its role in autoimmune diseases and cancer immunology. Activated CD8+ T cells directly kill target cells. Therefore, the regulation of their function is central to avoiding immunopathology. Mechanisms that curb effector functions in CD4+ and CD8+ T cells are mostly shared, yet important differences occur. Here, we focus on the control of CD8+ T cell activity and discuss the importance of a poorly understood aspect of tolerance that directly impairs engagement of target cells: the downregulation of CD8. We contextualize this process and propose that it represents a key element during CD8+ T cell modulation. [ABSTRACT FROM AUTHOR]

The proteasome generates the majority of peptides presented on MHC class I molecules. The cleavage pattern of the proteasome has been shown to be changed via the proteasome activator (PA)28 alpha beta (PA28αβ). In particular, several immunogenic peptides have been reported to be PA28αβ-dependent. In contrast, we did not observe a major impact of PA28αβ on the generation of different major histocompatibility complex (MHC) classI ligands. PA28αβ-knockout mice infected with the lymphocytic choriomeningitis virus (LCMV) or vaccinia virus showed a normal cluster of differentiation (CD) 8 response and viral clearance. However, we observed that the adoptive transfer of wild-type cells into PA28αβ-knockout mice led to graft rejection, but not vice versa. Depletion experiments showed that the observed rejection was mediated by CD8+ cytotoxic T cells. These data indicate that PA28αβ might be involved in the development of the CD8+ T cell repertoire in the thymus. Taken together, our data suggest that PA28αβ is a crucial factor determining T cell selection and, therefore, impacts graft acceptance. [ABSTRACT FROM AUTHOR]

Simple Summary: A widely used test to establish if a person has T-cells that react against an infection or against a cancer is the enzyme-linked ImmunoSpot (ELISPOT assay). The person's T-cells are mixed with short lengths of amino acids called peptides that span the protein targets (antigens) step-wise in an overlapping manner, in order to stimulate a measurable response in the form of countable spots on the membrane of the ELISPOT plate, which indicate cytokine secretion by individual T cells. Whilst research has shown that responsive peptides for certain individuals can be predicted by computer programs, we show that using large peptide pools representing several antigens reveal most effectively the majority of the T cell reactivity against viruses. Such an approach is also likely to be most effective in cancers. Synthetic peptides derived from antigen sequences are essential reagents for the detection of CD8+ cytotoxic T lymphocytes (CTLs), in assays such as ELISPOT/ImmunoSpot®. Indeed, the combination of peptides and ImmunoSpot® has been widely used for immune monitoring in numerous vaccine trials. Target antigens in pathogens or cancers may be large in size and multiple in number, often seemingly necessitating in silico peptide epitope predictions using algorithms and programs for certain HLA alleles to narrow down the numbers of required peptides. In this commentary, we discuss our data in the context of immune responses to viral and cancer antigens, concluding that systematic high-throughput immune monitoring of CD8+ T cells will provide more reliable insights on the host's response to cancer than the reliance on select CD8+ T cell epitopes, no matter whether these are in silico predicted or even if they had been empirically established. We show the feasibility of large scale, high-throughput systematic CD8+ T cell epitope testing towards this goal. [ABSTRACT FROM AUTHOR]

Infusion of 13C-labeled metabolites provides a gold standard for understanding the metabolic processes used by T cells during immune responses in vivo. Through infusion of 13C-labeled metabolites (glucose, glutamine, and acetate) in Listeria monocytogenes-infected mice, we demonstrate that CD8 T effector (Teff) cells use metabolites for specific pathways during specific phases of activation. Highly proliferative early Teff cells in vivo shunt glucose primarily toward nucleotide synthesis and leverage glutamine anaplerosis in the tricarboxylic acid (TCA) cycle to support adenosine triphosphate and de novo pyrimidine synthesis. In addition, early Teff cells rely on glutamic-oxaloacetic transaminase 1 (Got1)--which regulates de novo aspartate synthesis--for effector cell expansion in vivo. CD8 Teff cells change fuel preference over the course of infection, switching from glutamine-to acetate-dependent TCA cycle metabolism late in infection. This study provides insights into the dynamics of Teff metabolism, illuminating distinct pathways of fuel consumption associated with CD8 Teff cell function in vivo. [ABSTRACT FROM AUTHOR]

Killer cell lectin-like receptor G1 (KLRG1) has traditionally been regarded as an inhibitory receptor of T cell exhaustion in chronic infection and inflammation. However, its exact role in hepatitis B virus (HBV) infection remains elusive. CD8+ T cells from 190 patients with chronic hepatitis B were analyzed ex vivo for checkpoint and apoptosis markers, transcription factors, cytokines and subtypes in 190 patients with chronic hepatitis B. KLRG1+ and KLRG1− CD8+ T cells were sorted for transcriptome analysis. The impact of the KLRG1-E-cadherin pathway on the suppression of HBV replication mediated by virus-specific T cells was validated in vitro. As expected, HBV-specific CD8+ T cells expressed higher levels of KLRG1 and showed an exhausted molecular phenotype and function. However, despite being enriched for the inhibitory molecules, thymocyte selection-associated high mobility group box protein (TOX), eomesodermin (EOMES), and Helios, CD8+ T cells expressing KLRG1 produced significant levels of tumour necrosis factor (TNF)-α, interferon (IFN)-γ, perforin, and granzyme B, demonstrating not exhausted but active function. Consistent with the in vitro phenotypic assay results, RNA sequencing (RNA-seq) data showed that signature effector T cell and exhausted T cell genes were enriched in KLRG1+ CD8+ T cells. Furthermore, in vitro testing confirmed that KLRG1−E-cadherin binding inhibits the antiviral efficacy of HBV-specific CD8+ T cells. Based on these findings, we concluded that KLRG1+ CD8+ T cells are not only a terminally exhausted subgroup but also exhibit functional diversity, despite inhibitory signs in HBV infection. [ABSTRACT FROM AUTHOR]

According to the latest evidence, the microbial metabolite Urolithin A (UA), known for its role in promoting cellular health, modulates CD8+ T cell‐mediated antitumor activity. However, the direct target protein of UA and its underlying mechanism remains unclear. Here, this research identifies ERK1/2 as the specific target crucial for UA‐mediated CD8+ T cell activation. Even at low doses, UA markedly enhances the persistence and effector functions of primary CD8+ cytotoxic T lymphocytes (CTLs) and human chimeric antigen receptor (CAR) T cells both in vitro and in vivo. Mechanistically, UA interacts directly with ERK1/2 kinases, enhancing their activation and subsequently facilitating T cell activation by engaging ULK1. The UA‐ERK1/2‐ULK1 axis promotes autophagic flux in CD8+ CTLs, enhancing cellular metabolism and maintaining reactive oxygen species (ROS) levels, as evidenced by increased oxygen consumption and extracellular acidification rates. UA‐treated CD8+ CTLs also display elevated ATP levels and enhanced spare respiratory capacity. Overall, UA activates ERK1/2, inducing autophagy and metabolic adaptation, showcasing its potential in tumor immunotherapy and interventions for diseases involving ERKs. [ABSTRACT FROM AUTHOR]

Tumor vaccines, a crucial immunotherapy, have gained growing interest because of their unique capability to initiate precise anti-tumor immune responses and establish enduring immune memory. Injected tumor vaccines passively diffuse to the adjacent draining lymph nodes, where the residing antigen-presenting cells capture and present tumor antigens to T cells. This process represents the initial phase of the immune response to the tumor vaccines and constitutes a pivotal determinant of their effectiveness. Nevertheless, the granularity paradox, arising from the different requirements between the passive targeting delivery of tumor vaccines to lymph nodes and the uptake by antigen-presenting cells, diminishes the efficacy of lymph node-targeting tumor vaccines. This study addressed this challenge by employing a vaccine formulation with a tunable, controlled particle size. Manganese dioxide (MnO2) nanoparticles were synthesized, loaded with ovalbumin (OVA), and modified with A50 or T20 DNA single strands to obtain MnO2/OVA/A50 and MnO2/OVA/T20, respectively. Administering the vaccines sequentially, upon reaching the lymph nodes, the two vaccines converge and simultaneously aggregate into MnO2/OVA/A50-T20 particles through base pairing. This process enhances both vaccine uptake and antigen delivery. In vitro and in vivo studies demonstrated that, the combined vaccine, comprising MnO2/OVA/A50 and MnO2/OVA/T20, exhibited robust immunization effects and remarkable anti-tumor efficacy in the melanoma animal models. The strategy of controlling tumor vaccine size and consequently improving tumor antigen presentation efficiency and vaccine efficacy via the DNA base-pairing principle, provides novel concepts for the development of efficient tumor vaccines. [ABSTRACT FROM AUTHOR]