Association of T cell dysfunction with the presence of IgG autoantibodies on CD4+ lymphocytes in haemophilia patients; results of a 10-year study

HIV induces progressive dysfunction followed by numerical depletion of CD4⁺ lymphocytes. IgG autoantibodies and gp120-containing immune complexes have been implicated in the pathogenesis of AIDS. We carried out a longitudinal study in 19 HIV^– and 72 HIV⁺ haemophilia patients over a 10-year period in order to investigate a possible relationship between the occurrence of autoantibodies and CD4⁺ lymphocyte changes. IgM, IgG, C3d and gp120 on the surface of CD4⁺ lymphocytes were determined in heparinized whole blood with flow cytometry and double-fluorescence. The in vitro response of autoantibody-coated cells was tested in cell cultures with concanavalin A (Con A), phytohaemagglutinin (PHA), pokeweed mitogen (PWM), anti-CD3 MoAb or pooled allogeneic stimulator cells (MLC). After a 10-year follow up, 12 of 71 HIV⁺ and 16 of 19 HIV^– haemophilia patients showed no evidence of immunoglobulins on circulating CD4⁺ lymphocytes. HIV^– haemophilia patients without autoantibodies had CD4⁺and CD8⁺ cell counts in the normal range (957 ± 642/μl and 636 ± 405/μl) and normal T cell responses in vitro (mean relative response (RR) ≥ 0.7). In contrast, HIV⁺ haemophilia patients showed immunological abnormalities which were associated with the autoantibody and immune complex load of CD4⁺ blood lymphocytes. HIV⁺ patients without autoantibodies had a mean CD4⁺ lymphocyte count of 372 ± 274/μl, a mean CD8⁺ lymphocyte count of 737 ± 435/μl, and normal T lymphocyte stimulation in vitro (mean RR ≥ 0.7). HIV⁺ patients with complement-fixing IgM on CD4⁺ lymphocytes had somewhat lower CD4⁺ (255 ± 246/μl, P= NS) and CD8⁺ (706 ± 468/μl, P= NS) lymphocyte numbers, and also normal T lymphocyte stimulation (mean RR ≥ 0.7) in vitro. However, patients with complement-fixing IgG autoantibodies showed a strong decrease of CD4⁺ (150 ± 146/μl, P< 0.02) and CD8⁺ (360 ± 300/μl, P< 0.02) lymphocytes and impaired CD4⁺ lymphocyte stimulation in vitro with a mean RR of 0.5 ± 0.5 for Con A (P= NS), 0.7 ± 0.8 for PHA (P< 0.03), 0.4 ± 0.4 for PWM (P= NS), 0.8 ± 1.2 for anti-CD3 MoAb (P< 0.04) and 0.7 ± 1.0 for pooled allogeneic stimulator cells (P= 0.05). Patients with gp120-containing immune complexes on CD4⁺ blood lymphocytes demonstrated strongly decreased CD4⁺(25 ± 35/μl, P< 0.0001) and CD8⁺ (213 ± 212/μl, P< 0.006) lymphocyte counts as well as strongly impaired T lymphocyte responses in vitro upon stimulation with PHA (RR 0.2 ± 0.1, P < 0.02), PWM (RR 0.2 ± 0.2, P= 0.05), anti-CD3 MoAb (RR 0.1 ± 0.1, P< 0.04), and allogeneic stimulator cells (RR 0.2 ± 0.1, P< 0.02). These data led us to speculate that autoantibody formation against CD4⁺ lymphocytes is an important mechanism in the pathogenesis of AIDS. We hypothesize that autoantibodies against circulating CD4⁺ lymphocytes inhibit CD4⁺ cell function, especially the release of cytokines, and induce CD4⁺ cell depletion. The reduction and dysfunction of CD4⁺ lymphocytes may be responsible for the CD8⁺ cell depletion observed in HIV⁺ patients.     

CD28 CD8 T cells are significantly reduced and correlate with disease duration in juveniles with type 1 diabetes

Type 1 diabetes (T1D) is a chronic disease caused by autoimmune destruction of insulin-producing pancreatic β-cells. T1D is typically diagnosed in children, but information regarding immune cell subsets in juveniles with T1D is scarce. Therefore, we studied various lymphocytic populations found in the peripheral blood of juveniles with T1D compared to age-matched controls (ages 2–17). One population of interest is the CD28⁻ CD8⁺ T cell subset, which are late-differentiated cells also described as suppressors. These cells are altered in a number of disease states and have been shown to be reduced in adults with T1D. We found that the proportion of CD28⁻ cells within the CD8⁺ T cell population is significantly reduced in juvenile type 1 diabetics. Furthermore, this reduction is not correlated with age in T1D juveniles, although a significant negative correlation between proportion CD28⁻ CD8⁺ T cells and age was observed in the healthy controls. Finally, correlation analysis revealed a significant and negative correlation between the proportion of CD28⁻ CD8⁺ T cells and T1D disease duration. These findings show that the CD28⁻ CD8⁺ T cell population is perturbed following onset of disease and may prove to be a valuable marker for monitoring the progression of T1D.     

Down-regulation of TET2 in CD3+ and CD34+ cells of myelodysplastic syndromes and enhances CD34+ cells proliferation

Aims and background: To investigate the expressions of TET2 mRNA in bone marrow CD3⁺ and CD34⁺ cells of the patients with myelodysplastic syndromes (MDS) and to study the effect of silencing TET2 by small interfering RNA (siRNA) on the biological characteristics of CD34⁺ cells. Methods: CD3⁺ and CD34⁺ cells were sorted by magnetic activated cell-sorting system from bone marrow of MDS patients and controls. The mRNA expressions of TET2 in bone marrow CD3⁺ and CD34⁺ cells of 28 MDS patients and 20 controls were detected by qPCR. The silencing effect of RNA interference (RNAi) on TET2 expression in CD34⁺ bone marrow cells of normal control was identified by qPCR and Western blot analysis. The cell cycle kinetics and cell apoptosis were then detected by flow cytometry. Results: The expression of TET2 mRNA in CD3⁺ and CD34⁺ cells was down-regulated in MDS compared with that in controls [(0.16±0.11) vs. (1.05±0.32) (P<0.001); (0.58±0.26) vs. (1.25±0.94) (P<0.005)]. The siRNA targeting TET2 suppressed the expression of TET2 in normal CD34⁺ cells. Meanwhile, the proliferation activity was significantly enhanced [G0/G1: (87.82±8.25)% vs. (92.65±7.06)% and (93.60±5.54)%, P<0.05; S: (11.50±8.31)% vs. (6.92±7.04)% and (5.95±5.53)%, P<0.05] and the apoptosis rate was declined [(21.28±9.73)% vs. (26.17±9.88)% and (26.20±9.78)%] in the cells which transfected with TET2 siRNA as compared to those in the cells transfected with scrambled siRNA and control cells. Conclusions: The TET2 expression of in CD3⁺ and CD34⁺ cells of MDS patients was decreased. Suppression of TET2 expression renders the CD34⁺ cells harboring more aggressive phenotype. This preliminary finding suggests that CD34⁺ cells lowering expression of TET2 may play an oncogenic role on myeloid tumor and CD3⁺ T cells of MDS patients may be derived from the malignant clone.     

CD4+ Th1 cells promote CD8+ Tc1 cell survival, memory response, tumor localization and therapy by targeted delivery of interleukin 2 via acquired pMHC I complexes

The cooperative role of CD4⁺ helper T (Th) cells has been reported for CD8⁺ cytotoxic T (Tc) cells in tumor eradication. However, its molecular mechanisms have not been well elucidated. We have recently demonstrated that CD4⁺ Th cells can acquire major histocompatibility complex/peptide I (pMHC I) complexes and costimulatory molecules by dendritic cell (DC) activation, and further stimulate naïve CD8⁺ T cell proliferation and activation. In this study, we used CD4⁺ Th1 and CD8⁺ Tc1 cells derived from ovalbumin (OVA)-specific T cell receptor (TCR) transgenic OT II and OT I mice to study CD4⁺ Th1 cell''s help effects on active CD8⁺ Tc1 cells and the molecular mechanisms involved in CD8⁺ Tc1-cell immunotherapy of OVA-expressing EG7 tumors. Our data showed that CD4⁺ Th1 cells with acquired pMHC I by OVA-pulsed DC (DC_OVA) stimulation are capable of prolonging survival and reducing apoptosis formation of active CD8⁺ Tc1 cells in vitro, and promoting CD8⁺ Tc1 cell tumor localization and memory responses in vivo by 3-folds. A combined adoptive T-cell therapy of CD8⁺ Tc1 with CD4⁺ Th1 cells resulted in regression of well-established EG7 tumors (5 mm in diameter) in all 10/10 mice. The CD4⁺ Th1’s help effect is mediated via the helper cytokine IL-2 specifically targeted to CD8⁺ Tc1 cells in vivo by acquired pMHC I complexes. Taken together, these results will have important implications for designing adoptive T-cell immunotherapy protocols in treatment of solid tumors.     

Tetraspanin CD63 is a regulator of HIV-1 replication

Macrophages and CD4⁺ T-cells are the major reservoirs for HIV-1 infection. CD63 is a tetraspanin transmembrane protein, which has been shown to play an essential role during HIV-1 replication in macrophages. In this study, we further confirm the requirement of CD63 in HIV-1 replication events in primary human CD4⁺ T-cells, dendritic cells, and a CD4⁺ cell line. Most interestingly, we also show the evidences for the co-localization and internalization of CD63 and HIV-1 major receptor CD4 in primary human macrophages and CD4⁺ cell line by confocal microscopy and Co-Immunoprecipitation assay. Analysis revealed that CD63-depleted CD4⁺ T-cells, dendritic cells, and a cell line showed significant decrease in HIV-1 production. Further analysis showed that CD63 down regulation reduced production of the early HIV protein Tat, and affected HIV protein Gag by CD63-Gag interaction. In agreement, CD63 silencing also inhibited production of the late protein p24. Furthermore, we revealed that CD63 silencing has no effect on HIV-1 replication with extensive viral challenge (MOI > 0.2). These findings suggest that CD63 plays a dual-role both in early and late HIV-1 life cycle with a range of HIV-1 infection (MOI < 0.2).     

Role of tumour necrosis factor-alpha (TNF-α) in the induction of HIV-1 gp120-mediated CD4+ T cell anergy

The HIV-1 envelope glycoprotein (gp120) is known to induce antigen-specific and non-specific CD4⁺ T cell anergy. We found that early T cell activation, as indicated by HLA-DP expression in the early G₁ (G_1A) phase of the cell cycle, and the inhibition of mitogen-mediated IL-2 production induced by gp120, required TNF-α produced by gp120-stimulated macrophages. In the presence of an antibody to TNF-α, these changes induced by gp120 were inhibited, while recombinant TNF-α induced similar abnormalities of CD4⁺ T cells, even in the absence of gp120. On the other hand, inhibition of the mixed lymphocyte reaction (MLR) in CD4⁺ T cells by gp120, which may be related to gp120-mediated down-regulation of CD4 expression on T cells and activation of protein tyrosine kinase p56^lck in CD4⁺ T cells, was observed even in the absence of macrophage-derived TNF-α induced by gp120. These observations indicate that both TNF-α-dependent and independent events contribute to gp120-mediated CD4⁺ T cell anergy, and TNF-α appears to play an important role in inducing CD4⁺ T cell anergy in HIV-1 infection.     

CD8+ T cells and not CD4+ T cells are hyporesponsive to CD28- and CD40L-mediated activation in HIV-infected subjects

T cell dysfunction in HIV-infected subjects could be the consequence of altered sensitivity of CD4⁺ or CD8⁺ T cells to various costimulatory signals. Therefore, we studied proliferation and cytokine production in highly purified CD8⁺ and CD4⁺ T cells from HIV-infected and HIV⁻ subjects, induced by co-activation via cell-bound CD80, CD86 and CD40 or by allo-activation. Regardless of the nature of the first and the costimulatory signal, CD8⁺ T cells from patients proliferated consistently less than controls, while responses from CD4⁺ T cells were similar in patients and controls. This phenomenon was observed after ligation of CD28 combined with anti-CD3 or phorbol myristate acetate (PMA), but also after allogeneic stimulation and after activation by CD40 and anti-CD3. Anti-CD3 combined with CD80 or CD86 induced a mixed Th1/Th2-type cytokine profile in both CD4⁺ and CD8⁺ T cells from controls, whereas anti-CD3 plus CD40 induced only low levels of Th2-type cytokines and no interferon-gamma (IFN-γ) in CD4⁺ T cells. Compared with controls, CD4⁺ T cells from patients produced slightly lower levels of IL-10 but equal amounts of IFN-γ, IL-4 and IL-5, while CD8⁺ T cells from patients produced less of all cytokines tested. In conclusion, responses of purified CD4⁺ T cells from HIV⁺ subjects to various costimulatory pathways are relatively intact, whereas CD8⁺ T cells are hyporesponsive at the level of proliferation and cytokine production. A generalized intrinsic CD8⁺ T cell failure might contribute to viral and neoplastic complications of HIV infection.     

Rapid identification and sorting of viable virus-reactive CD4(+) and CD8(+) T cells based on antigen-triggered CD137 expression

Current methods for the detection and isolation of antigen-specific CD4⁺ and CD8⁺ T cells require the availability of peptide/MHC multimers or are restricted to cells that produce cytokines after antigen contact. Here we show that de novo cell surface expression of the TNF-receptor family member CD137 (4-1BB) identifies recently activated, but not resting, human CD4⁺ and CD8⁺ memory T cells. Maximum CD137 expression level is uniformly observed in both T-cell subsets at 24h after stimulation with antigen. In experiments with CMV and EBV-reactive T cells, we confirmed the specificity of CD137 expression by co-staining with peptide/HLA tetramers. Substantial proportions of CD137⁺ T cells did not produce IFN-γ, suggesting that CD137 detects a broader repertoire of antigen-specific T cells. Activated CD137⁺ T cells could be easily purified by MACS and expanded in vitro thereafter. This CD137-based enrichment method was capable of isolating 2-fold higher numbers of anti-viral CD4⁺ and CD8⁺ T cells compared to the IFN-γ secretion assay. In conclusion, antigen-triggered CD137 expression allows the rapid detection and sorting of virus-reactive CD4⁺ and CD8⁺ T cells. The CD137 assay is most attractive for the simultaneous targeting of anti-viral T helper and effector cells in monitoring studies and adoptive immunotherapy trials.     

CD8+ lymphocyte phenotype and cytokine production in long-term non-progressor and in progressor patients with HIV-1 infection

In most HIV-1-infected patients, clinical and immunological progression develops within a few years. Few infected people, termed long-term non-progressors (LTNP), remain healthy and immunologically stable for a long time. The factors governing the maintenance of this condition are not well known, but it is conceivable that CD8⁺ lymphocytes, cells that play a central role in controlling in vitro HIV replication, may have a part in vivo in this process. The aim of this study was to characterize the phenotypic profile and the cytokine production of CD8⁺ cells in a group of LTNP patients who had stable CD4⁺ cell counts (>500/mm³) for at least 7 years. Their CD8⁺ absolute numbers were similar to a control group composed of HIV-1⁺ patients who have a progressive decline of their CD4⁺ cell counts. However, our multiparameter immunofluorescence studies show that a clinical and immunologically stable condition is associated with the presence of a CD28⁺, CD95 strongly positive CD8⁺ population, while disease progression is marked by the CD28⁻CD95⁺CD8⁺ subset. Purified CD8⁺ cells from LTNP retain their ability to produce IL-2, interferon-gamma (IFN-γ) and, to a lesser degree, to produce IL-10 and IL-4. In contrast, CD8⁺ cells from progressors are unable to secrete IL-2 and IL-10. Although CD8⁺ cytokine profile does not fit with the proposed T helper (Th)1/Th2 switch in progressive HIV infection, LTNP CD8⁺ T cells maintain their capacity to produce IL-2 and IL-10 (Th0-like), a pattern very similar to that observed in normal HIV healthy controls. We suggest that CD8⁺ cells expressing CD28, CD95 and having a Th0-like profile may be considered to be associated with long-term survival.     

CD4+CD25+ Treg induction by an HSP60‐derived peptide SJMHE1 from Schistosoma japonicum is TLR2 dependent

Chronic schistosome infection results in the suppression of host immune responses, allowing long‐term schistosome survival and restricting pathology. Current theories suggest that Treg play an important role in this regulation. However, the mechanism of Treg induction during schistosome infection is still unknown. The aim of this study was to determine the mechanism behind the induction of CD4⁺CD25⁺ T cells by Schistosoma japonicum HSP60 (SjHSP60)‐derived peptide SJMHE1 as well as to elucidate the cellular and molecular basis for the induction of CD4⁺CD25⁺ T cells during S. japonicum infection. Mice immunized with SJMHE1 or spleen and LN cells from naïve mice pretreated with SJMHE1 in vitro all displayed an increase in CD4⁺CD25⁺ T‐cell populations. Release of IL‐10 and TGF‐β by SJMHE1 stimulation may contribute to suppression. Adoptively transferred SJMHE1‐induced CD4⁺CD25⁺ T cells inhibited delayed‐type hypersensitivity in BALB/c mice. Additionally, SJMHE1‐treated APC were tolerogenic and induced CD4⁺ cells to differentiate into suppressive CD4⁺CD25⁺ Treg. Furthermore, our data support a role for TLR2 in SJMHE1‐mediated CD4⁺CD25⁺ Treg induction. These findings provide the basis for a more complete understanding of the S. japonicum–host interactions that contribute to host homeostatic mechanisms, preventing an excessive immune response.     

CD4+CD29+T cells are blamed for the persistent inflammatory response in ulcerative colitis

Ulcerative colitis (UC) is a chronic gastrointestinal disorder eliciting occurrence of colorectal cancer, the third most common human malignancy. The diagnosis of UC is based on clinical symptoms combined with typical findings on endoscopy, radiology, and ultimately pathology. We investigated the variation trend of CD4⁺CD29⁺T cells together with MPO, VCAM-1 in different periods of rat UC model and UC patients. We also evaluated the relationship between CD4⁺CD29⁺T cells and disease severity. UC model was induced by administering DNCB liquid and acetate solution. We found upregulated expression of CD4⁺CD29⁺T cells in both peripheral blood and colon from rats, and a similar trend for MPO and VCAM-1 in colon (P < 0.05); the expression was especially enhanced in UC rats at two weeks after the model was established (P < 0.01). Such upregulation was also indicated in active and remission UC patients as compared to the healthy and enteritis groups (P < 0.05), with the highest expression level detected in the active UC patients (P < 0.01). Pearson correlation analysis showed a positive correlation of CD4⁺CD29⁺T cells in rat and human peripheral blood with DAI score (r_rat = 0.712, r_human = 0.677, P < 0.01), and MPO in colon (r_rat = 0.514, r_human = 0.682, P < 0.05). These results suggest that CD4⁺CD29⁺T cells may act as major effector cell subsets in persistent inflammatory responses for UC and that infiltration into colon inflammation may be induced by the combination of VCAM-1 and CD29.     

Bright expression of CD91 identifies highly activated human dendritic cells that can be expanded by defensins

CD91 is a scavenger receptor expressed by different immune cells and its ligands defensins have been demonstrated to contribute to immune responses against infections and tumours. We previously demonstrated that CD91 is expressed on human monocyte-derived dendritic cells (moDCs) and that human defensins stimulate in vitro the activation of these cells. In this study, we observed that CD91 is expressed at different levels on two distinct moDC subsets: CD91^dim and CD91^bright moDCs. Although CD91^bright moDCs represented a small proportion of total moDCs, this subset showed higher levels of activation and maturation markers compared with CD91^dim moDCs. The frequency of CD91^bright moDCs increased by ∼ 50% after in vitro stimulation with recombinant human neutrophil peptide-1 (rHNP-1) and recombinant human β defensin-1 (rHBD-1), while lipopolysaccharide (LPS) stimulation decreased it by ∼ 35%. Both defensins up-regulated moDC expression of CD80, CD40, CD83 and HLA-DR, although to a lower extent compared with LPS. Notably, upon culture with rHNP-1 and rHBD-1, CD91^bright moDCs maintained their higher activation/maturation status, whereas this was lost upon culture with LPS. Our findings suggest that defensins promote the differentiation into activated CD91^bright DCs and may encourage the exploitation of the CD91/defensins axis as a novel therapeutic strategy to potentiate antimicrobial and anti-tumour immune response.     

Soluble PD-1 rescues the proliferative response of simian immunodeficiency virus-specific CD4 and CD8 T cells during chronic infection

Phenotypic and functional studies of the programmed death-1 (PD-1) molecule on CD4⁺ and CD8⁺ T cells were performed on peripheral blood mononuclear cells from uninfected and simian immunodeficiency virus (SIV)-infected rhesus macaques. These data demonstrated a rapid upregulation of PD-1 expression on tetramer-positive CD8⁺ T cells from MamuA.01⁺ SIV-infected macaques upon infection. Upregulation of PD-1 on total CD8⁺ T cells was not detectable. In contrast, CD4⁺ T-cell PD-1 expression was markedly higher in total CD4⁺ T cells during chronic, but not acute, infection and there was a correlation between the level of PD-1 expression on naive and central memory CD4⁺ T cells and the levels of viral loads. Such association was emphasized further by a marked decrease of PD-1 expression on tetramer-positive CD8 T cells as well as on CD4⁺ T cells on longitudinal samples collected before and after the initiation of antiretroviral therapy and downregulation of viral replication in vivo. Cloning of PD-1 and its two ligands from several non-human primate species demonstrated > 95% conservation for PD-1 and PD-L2 and only about 91% homology for PD-L1. Functional studies using soluble recombinant PD-1 protein or PD-1–immunoglobulin G fusion proteins induced marked increases in the SIV-specific proliferative responses of both CD4⁺ and CD8⁺ T cells from rhesus macaques. The results of these studies serve as a foundation for future in vivo trials of the use of rMamu-PD-1 to potentially enhance and/or restore antiviral immune responses in vivo.     

Type 1 and type 2 cytokine-producing mouse CD4+ and CD8+ T cells in acute Schistosoma mansoni infection

CD4⁺ and CD8⁺ T cells can be divided based on the cytokines that they secrete into type 1 (Th1, Tc1) and type 2 (Th2, Tc2) subsets. Schistosoma mansoni infection in mice is characterized by a type 2-dominated response. We have used intracellular cytokine staining to demonstrate dramatic changes in the relative numbers of Tc1 and Th2 cells in the spleens of mice during acute schistosome infection. In infected mice prior to egg laying a generalized type 1 response dominated, and was associated with an expansion in the frequency of Tc1 and Th1 cells. By week 7 after infection the cytokine response was of type 2, with an increase in the numbers of Th2 cells and a dramatic reduction in the frequency of Tc1 cells. Following the onset of egg laying there was apoptosis of cells in the spleens of mice, with CD4⁺ and in particular CD8⁺ T cells undergoing apoptosis. The loss of CD8⁺ T cells may in part be attributable to the development of a type 2 environment, following egg laying, with type 2 responses mediating the apoptosis of Tc1 cells. Schistosome regulation of Tc1 during egg laying may be required to prevent type 1 inflammatory responses from exacerbating egg-induced pathology.     

Circulating CD137+CD8+ T cells accumulate along with increased functional regulatory T cells and thoracic tumour burden in lung cancer patients

CD137 is a promising target for immunostimulation strategies against cancer. Previous studies showed that CD137⁺CD8⁺ T cells are enriched in antitumour effector T cells in both preclinical tumour models and cancer patients, but to date, such T cells in the blood of lung cancer patients have not been sufficiently investigated. In this study, circulating antigen‐activated CD8⁺ T cell subsets, identified as CD137⁺CD8⁺ or PD‐1⁺ (programmed cell death protein 1) CD8⁺, and regulatory T cells (Treg), identified as CD4⁺CD25⁺CD127^low/?, in 40 untreated lung cancer patients and in 49 age‐ and sex‐matched healthy controls (HCs) were assessed by flow cytometry. Results were evaluated for associations with lung cancer patient clinical characteristics. Correlations between antigen‐activated CD8⁺ T cells and effector Treg (CTLA‐4⁺ [cytotoxic T‐lymphocyte antigen 4] CD4⁺CD25⁺CD127^low/?) were also investigated. Higher percentages of PD‐1⁺, CD137⁺ and PD‐1⁺CD137⁺ amongst CD8⁺ T cells were observed in lung cancer patients compared with HCs. The percentages of CD137⁺CD8⁺ and PD‐1⁺CD137⁺CD8⁺ T cell subsets amongst CD8⁺ T cells were positively correlated with thoracic tumour burden and were strongly positively correlated with the percentage of effector Treg subset. Smoking patients harboured higher percentages of the PD‐1⁺CD8⁺ T cell subset compared with non‐smoking patients. This study demonstrated that circulating antigen‐activated CD8⁺ T cells accumulated in lung cancer patients along with increased effector Treg and thoracic tumour burden. These findings aid a better understanding of immune‐host interactions in lung cancer patients using peripheral blood, and further support immunotherapeutic intervention strategies using combination therapy for differential control of Treg and activation of tumour‐specific effector T cells.     

Prognostic Values of CD38+CD101+PD1+CD8+ T Cells in Pancreatic Cancer

Programmed death-1 (PD-1), a key immune checkpoint molecule, has been developed as an oncotherapy target for various carcinomas. However, treatment with anti-PD-1 elicited only a minimal effect in pancreatic ductal adenocarcinoma (PDAC). Subsequent studies revealed the existence of a subset of PD-1⁺ T cells coexpressing CD38 and CD101, representing a fixed dysfunctional subpopulation that are not able to be rescued by anti-PD-1 immunotherapy. However, whether this subpopulation of PD-1 expressing CD8⁺ T cells could be useful in predicting PDAC stage or prognosing survival is unknown. In this study, we used flow cytometry and immunofluorescence assay to analyze the expression of CD38 and CD101 in 183 clinical PDAC samples, including 84 of peripheral blood and 99 of surgical tissues. High coexpression of CD38/CD101 on peripheral PD-1⁺CD8⁺ T cells or tumor-infiltrating lymphocytes (TILs) was found to be most significantly correlated with Tumor/Node/Metastasis (T/N/M) classification and clinical stage, in contrast PD-1⁺CD8⁺ T cells could not correlate with T classification. CD38/CD101 co-repression on TILs also correlated with the poor survival in these PDAC patient samples. Our data suggest that CD38/CD101 might represent a more helpful biomarker than PD-1 alone for diagnosis and prognosis of PDAC.     

Demonstration of identical expanded clones within both CD8+ CD28+ and CD8+ CD28− T cell subsets in HIV type 1-infected individuals

In HIV-1-infected individuals, the CD8⁺ CD28⁻ T cell subset is considerably expanded and is frequently the largest subset of T cells found in peripheral blood. It has been assumed, but not proven, that CD8⁺ CD28⁻ T cells derive from CD8⁺ CD28⁺ T cells in vivo. To further study the ontogeny of CD8⁺ CD28⁻ T cells, we have performed analyses of the complementarity determining region 3 (CDR3) of the TCRB of CD8⁺ CD28⁺ and CD8⁺ CD28⁻ T cells from the peripheral blood of HIV-1-infected individuals. When cells from the same individual were compared, expanded peaks in CDR3 length analysis within a given BV family were frequently observed at the same location in both CD8⁺ subsets ( p < 0.001). Sequencing of cDNA corresponding to dominant peaks revealed the presence of identical expanded CD8⁺ T cell clones within both the CD28⁺ and CD28⁻ subsets on eight of nine attempts. Our results show that CD8⁺ CD28⁺ and CD8⁺ CD28⁻ T cells are phenotypic variants of the same lineage, most likely evolving from CD8⁺ CD28⁺ to end-stage CD8⁺ CD28⁻ T cells.     

Properties of HTLV-I transformed CD8 T-cells in response to HIV-1 infection

HIV-1 infection studies of primary CD8⁺ T-cells are hampered by difficulty in obtaining a significant number of targets for infection and low levels of productive infection. Further, there exists a paucity of CD8-expressing T-cell lines to address questions pertaining to the study of CD8⁺ T-cells in the context of HIV-1 infection. In this study, a set of CD8⁺ T-cell clones were originated through HTLV-I transformation in vitro, and the properties of these cells were examined. The clones were susceptible to T-cell tropic strains of the virus and exhibited HIV-1 production 20-fold greater than primary CD4⁺ T-cells. Productive infection resulted in a decrease in expression of CD8 and CXCR4 molecules on the surface of the CD8⁺ T-cell clones and antibodies to these molecules abrogated viral binding and replication. These transformed cells provide an important tool in the study of CD8⁺ T-cells and may provide important insights into the mechanism(s) behind HIV-1 induced CD8⁺ T-cell dysfunction.     

Low expression of CD39+/CD45RA+ on regulatory T cells (Treg) cells in type 1 diabetic children in contrast to high expression of CD101+/CD129+ on Treg cells in children with coeliac disease

Type 1 diabetes (T1D) and coeliac disease are both characterized by an autoimmune feature. As T1D and coeliac disease share the same risk genes, patients risk subsequently developing the other disease. This study aimed to investigate the expression of T helper (Th), T cytotoxic (Tc) and regulatory T cells (T_reg) in T1D and/or coeliac disease children in comparison to healthy children. Subgroups of T cells (Th : CD4⁺ or Tc : CD8⁺); naive (CD27⁺CD28⁺CD45RA⁺CCR7⁺), central memory (CD27⁺CD28⁺CD45RA⁻CCR7⁺), effector memory (early differentiated; CD27⁺CD28⁺CD45RA⁻CCR7⁻ and late differentiated; CD27⁻CD28⁻CD45RA⁻CCR7⁻), terminally differentiated effector cells (TEMRA; CD27⁻CD28⁻CD45RA⁺CCR7⁻) and T_reg (CD4⁺CD25⁺FOXP3⁺CD127⁻) cells, and their expression of CD39, CD45RA, CD101 and CD129, were studied by flow cytometry in T1D and/or coeliac disease children or without any of these diseases (reference group). Children diagnosed with both T1D and coeliac disease showed a higher percentage of TEMRA CD4⁺ cells (P < 0·05), but lower percentages of both early and late effector memory CD8⁺ cells (P < 0·05) compared to references. Children with exclusively T1D had lower median fluorescence intensity (MFI) of forkhead box protein 3 (FoxP3) (P < 0·05) and also a lower percentage of CD39⁺ and CD45RA⁺ within the T_reg population (CD4⁺CD25⁺FOXP3⁺CD127⁻) (P < 0·05). Children with exclusively coeliac disease had a higher MFI of CD101 (P < 0·01), as well as a higher percentage of CD129⁺ (P < 0·05), in the CD4⁺CD25^hi lymphocyte population, compared to references. In conclusion, children with combined T1D and coeliac disease have a higher percentage of differentiated CD4⁺ cells compared to CD8⁺ cells. T1D children show signs of low CD39⁺/CD45RA⁺ T_reg cells that may indicate loss of suppressive function. Conversely, children with coeliac disease show signs of CD101⁺/CD129⁺ T_reg cells that may indicate suppressor activity.