Expression of Adhesion Molecules and CD28 on T Lymphocytes during Human Immunodeficiency Virus Infection

Adhesion molecules, which play a major role in lymphocyte circulation, have not been well characterized in human immunodeficiency virus (HIV) infection. T-lymphocyte populations, including CD3, CD4, CD28, and adhesion molecules (L selectin, LFA-1, VLA-4, and ICAM-1) were measured by flow cytometry in a cross-sectional study of 100 HIV-infected and 49 HIV-seronegative adults. HIV-infected adults had lower numbers of CD3⁺ lymphocytes expressing L selectin (P < 0.0001) and VLA-4 (P < 0.01) and higher numbers of CD3⁺ lymphocytes expressing LFA-1^bright (P < 0.002) than did HIV-negative adults. By CD4⁺-lymphocyte count category (>500, 200 to 500, or <200 cells/μl), HIV-infected adults with more advanced disease had lower percentages of CD3⁺ lymphocytes expressing L selectin and VLA-4 and higher percentages of CD3⁺ lymphocytes expressing LFA-1. The percentages of CD3⁺ CD28⁺ lymphocytes and of CD3⁺ L selectin⁺ lymphocytes were positively correlated (Spearman coefficient = 0.86; P < 0.0001), and the percentage of CD3⁺ CD28⁺ lymphocytes and the CD3⁺ LFA-1^bright lymphocyte/CD3⁺ LFA-1^dim lymphocyte ratio were negatively correlated (Spearman coefficient = −0.92; P <0.00001). The results of this study suggest that HIV infection is associated with altered expression of adhesion molecules.     

Sustained CD28 Expression Delays Multiple Features of Replicative Senescence in Human CD8 T Lymphocytes

CD28 costimulatory signal transduction in T lymphocytes is essential for optimal telomerase activity, stabilization of cytokine mRNAs, and glucose metabolism. During aging and chronic infection with HIV-1, there are increased proportions of CD8 T lymphocytes that lack CD28 expression and show additional features of replicative senescence. Moreover, the abundance of these cells correlates with decreased vaccine responsiveness, early mortality in the very old, and accelerated HIV disease progression. Here, we show that sustained expression of CD28, via gene transduction, retards the process of replicative senescence, as evidenced by enhanced telomerase activity, increased overall proliferative potential, and reduced secretion of pro-inflammatory cytokines. Nevertheless, the transduced cultures eventually do reach senescence, which is associated with increased CTLA-4 gene expression and a loss of CD28 cell surface expression. These findings further elucidate the central role of CD28 in the replicative senescence program, and may ultimately lead to novel therapies for diseases associated with replicative senescence.     

Differential Expression of CD30 on CD3 T Lymphocytes in Patients with Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune systemic disease caused as a result of an imbalance of Th1‐/Th2‐type cytokines. The soluble form of CD30 (CD30s) released from peripheral blood cells has been described as a marker of active disease in Th2‐type immune response as in SLE. However, the expression of CD30 on CD3 T lymphocytes from patients with SLE has not been studied yet. Therefore, we have addressed our study to attempt this issue, studying CD30 expression by flow cytometry on CD3 T lymphocytes and CD4/CD8 subsets in samples from SLE patients mainly with lupus nephritis. In parallel, we have determined the production of the cytokines IL‐4 (Th2), IFNγ (Th1), IL‐10 and TGFβ by intracellular staining. Differences between positive CD30 T cells in healthy controls and patients with SLE were found, with a higher percentage of CD30‐expressing T cells in patients with SLE (P = 0.001). In contrast to healthy controls, CD30 was mainly expressed on CD8 T cells from patients with SLE. The intracellular cytokine staining showed that TGFβ is the main cytokine expressed in CD3 T cells from patients with SLE. In addition to this, we have found a positive correlation between CD30‐expressing T cells and IL‐4, IFNγ, and immunosuppressive cytokines (IL‐10 and TGFβ) (P < 0.05). These results suggest that CD30 could play a role in the pathogenesis of SLE and its expression on CD3 T lymphocytes is not restricted only to Th2‐type response.     

Expression of CD80 and CD86 on Peripheral Blood T Lymphocytes in Patients with Systemic Lupus Erythematosus

CD80 and CD86 were detected in high amounts on circulating T cells in the peripheral blood of some patients with systemic lupus erythematosus (SLE), using flow cytometry and monoclonal antibodies. Patients with other connective tissue diseases did not have a high percentage of T cells expressing CD80 or CD86 in their peripheral blood. CD80 was expressed mainly on CD4 T cells, whereas CD86 was expressed on CD8 T cells, and these two populations were associated with paticular clinical features. These two molecules were expressed on different T-cell populations and might have different roles in the generation and regulation of immune responses. Since high expression of CD86 on T cells was detected much earlier than the appearance of clinical features and a high titer of anti-DNA antibody, it may be a useful parameter for predicting the flare of SLE.     

Distribution of Alloreactivity Amongst the CD45 Isoforms of Circulating CD4 and CD8 T Lymphocytes

The expression of different isoforms of the CD45 surface molecule allows lymphocytes to be divided into two nonoverlapping categories, CD45RA and CD45RO. Previous studies of CD4 T cells have shown that responses to soluble antigens are present predominantly in the RO subset and to mitogens in the RA, alloreactivity being present in both subsets. Responses of CD8 T cells have not been investigated in such detail, nor have responses been compared to CD4 cells. Here we report the alloreactive responses of both CD45RA and RO subsets amongst both CD4 and CD8 T lymphocytes. Following isolation of CD4 and CD8 cells with immunomagnetic beads, CD45 subsets were separated by negative depletion using specific monoclonal antibodies. CD45RA populations were greater than 97% pure and CD45RO cells greater than 91%. One-way primary mixed lymphocyte reactions were established using the purified responder cells with irradiated allogeneic peripheral blood mononuclear cells as stimulators; experiments were all repeated at least three times. In assays of CD4⁺ RA and RO subsets, reactivity was present in both isoforms, being consistently, but not significantly, greater amongst the RO subset. With CD8⁺ T cells, reactivity was also present in both isoforms, but was significantly greater in the CD45RA subset, with mean proliferation 2.5–3-fold that of the CD45RO cells ( P  < 0.05).     

Active Crohn's Disease Patients Show a Distinctive Expansion of Circulating Memory CD4+CD45RO+CD28null T Cells

In a previous study we found an expansion of circulating memory (CD45RO(+)) CD4(+) T cells in patients with Crohn's disease (CD). The aim of this work was to investigate the phenotypic and functional characteristics of this T-cell subset in CD. We analyzed in peripheral blood CD4(+)CD45RO(+) T cells from CD patients the expression of surface markers associated to immune activation, costimulation, and apoptosis. In sorted CD4(+)CD45RO(+) T cells apoptosis was quantified by fluorescent annexin V binding. Healthy subjects and patients with ulcerative colitis and acute bacterial enterocolitis served as control groups. An increased percentage of memory CD4(+)CD45RO(+) T cells lacking the expression of costimulatory receptor CD28 was detected in patients with active CD when compared to the other groups evaluated. This expanded CD4(+)CD45RO(+)CD28(null) T-cell subset expressed mostly the effector-cell marker CD57(+). Both CD28 downregulation and CD57 expression correlated to CDAI and surrogate markers of disease activity. These phenotypic changes observed on CD4(+)CD45RO(+) T cells from active CD returned to values similar to healthy controls after clinical remission. Moreover, this memory CD28(null) T-cell subset might express more intracytoplasmic TNF and IFN-gamma than their CD28(+) counterpart. Significantly lower frequencies of memory CD4(+)CD45RO(+) T cells expressing CD95 apoptosis receptor were found in patients with active CD. Moreover, sorted CD4(+)CD45RO(+)and CD4(+)CD45RO(+) CD28(null) T cells from patients with active CD exhibited a lower apoptotic rate than that found in healthy controls and inactive CD patients. According to our data, circulating T lymphocytes from active CD patients show distinctive phenotypic and functional changes, characterized by an expansion of memory CD4(+)CD45RO(+)CD28(null) T cells expressing effector-associated cell surface molecules and displaying enhanced resistance to apoptosis.     

HLA-DR Expression on Cytotoxic T Lymphocytes

A DR-null and DQ-null mutant lymphoblastoid cell line (LCL) was used to generate cytotoxic T cells (CTL) to investigate DR expression on CTL. Effector T cells generated in human allogeneic mixed lymphocyte culture (MLC) were separated on a fluorescence-activated cell sorter (FACS) into DR-positive and DR-negative subsets. The great majority of detectable cytolytic activity, anti-class I and anti-class II (presumably anti-DP) CTL, as well as natural killer (NK)-like activity, resided within the DR-positive population.     

CD40在系统性红斑狼疮外周血淋巴细胞的表达

使用密度离心法分离SLE患者和正常人外周血单个核细胞 (PBMC ) ,采用流式细胞术检测B淋巴细胞白细胞分化抗原 4 0 (CD4 0 )的表达水平 ,进行SLE患者 (活动期和缓解期 )和正常人之间的比较 ;并进行B淋巴细胞CD4 0表达水平和血清抗dsDNA抗体水平及狼疮活动指数 (SLEDAI)的相关分析。结果表明 ,活动期SLE患者外周血B淋巴细胞比例 (% )和其表达CD4 0的比例 (% )均明显高于缓解期SLE患者和对照组 ,其表达CD4 0的平均荧光强度 (MFI)在活动期SLE患者最高 ,缓解期SLE患者稍低 ,对照组最低 ;相关分析结果表明 ,活动期SLE患者B淋巴细胞CD4 0的表达比例 (% )和强度 (MFI)均与血清抗dsDNA抗体及SLEDAI呈正相关 ,后两者呈高度相关 ;缓解期SLE患者B淋巴细胞表达CD4 0的强度 (MFI)和SLEDAI呈正相关。CD4 0在活动期SLE患者B淋巴细胞的表达增加 ,其水平与疾病活动度有关。     

Expression of CD26 (Dipeptidyl Peptidase IV) on Memory and Naive T Lymphocytes

It has been suggested that human CD26-positive T lymphocytes represent the memory pool of the cellular immune system. For proof of this suggestion we analysed the responsiveness of CD26-positive and CD26-negative T lymphocytes after antigenic stimulation in limiting dilution experiments. After stimulation with tetanus toxoid (TT) the number of proliferating cells within the CD26-positive subset was two- to sixfold higher than that within the CD26-negative subset. These differences in responsiveness were also detectable between CD4+/CD26+ and CD4+/CD26- T cells. To further investigate the memory character of the cells, human peripheral blood mononuclear cells were stimulated with TT for 7 or 14 days. Thereafter, CD26+ and CD26- T cells were isolated and restimulated with TT in limiting dilution experiments. Responding cells were found not only within the CD26-positive subset but also within the CD26-negative subset, and their number increased with time. Surface marker analysis of freshly isolated human T lymphocytes or T-cell clones indicated that CD26 is not a stable cell surface marker. Furthermore, CD26 is both absent and present on CD29-positive or CD45RA-positive cells, indicating no association of CD26 with surface markers for memory or naive T cells, respectively. These results strongly argue against the hypothesis that CD26-positive T cells represent the memory pool. We conclude that CD26 is an activation marker of T lymphocytes, which is associated with reactivity on naive and memory cells.     

重症肌无力患者外周血CD5~+B细胞和CD4~-CD8~-T细胞的变化

研究重症肌无力 (MG )患者外周血CD5 + B细胞和CD4 CD8 T细胞的变化 ,以探讨这两种细胞与MG的关系。采用流式细胞仪分析MG患者和对照组外周血中CD5 + B细胞和CD4 CD8 T细胞的频率 ,同时以ELISA方法检测这些患者的血清AchR、PsmR抗体水平。结果 :2 8例MG患者的CD5 + B细胞为 19 75 %± 10 8% ,高于对照组的 15 4 %± 9 6 7% (P <0 0 1) ;胸腺未切除MG患者的CD5 + B细胞为 2 2 31%± 7 4 7% ,显著高于对照组 (P <0 0 0 1) ;两种抗体阳性MG患者的CD5 + B细胞为 2 4 96 %± 13 1% ,显著高于对照组 (P <0 0 0 1) ;以上各组MG患者的CD4 CD8 T细胞与对照组均无显著区别 ;两种抗体阴性组的CD5 + B细胞和CD4 CD8 T细胞亦与对照组均无显著区别 ;两种抗体阴性组的CD5 + B细胞和CD4 CD8 T细胞亦与对照组无明显差异。本研究提示MG患者外周血的CD5 + B细胞频率增高 ,与胸腺切除与否以及突触前后膜抗体的阳性程度密切相关 ,而CD4 CD8 T细胞是否与MG有关还需进一步研究证实。     

多发性骨髓瘤患者外周血CD4~+CD25~+和CD8~+CD28~-调节性T细胞研究

目的:探讨CD4~+CD25~+和CD8~+CD28~-调节性T细胞(Tregs)在多发性骨髓瘤(MM)患者外周血中的变化及意义.方法:采用流式细胞术检测38例MM患者及20例健康对照外周血CD4~+CD25~+和CD8~+CD28~-Tregs水平.分别采用溴甲酚绿法、透射免疫比浊法测定患者血清白蛋白(Alb)、β2-微球蛋白(β2-MG).结果:初诊MM患者外周血CD4~+CD25~(+/high)、CD4~+CD25~(high)CD127~(low)及CD8~+CD28~-Tregs比率均明显升高;CD4~+CD25~(+/high)和CD4~+CD25~)(high)CD127~(low)Tregs比率在各临床分期均较对照组升高,随分期增高呈现增加趋势,且CD4~+CD25~(high)和CD4~+CD25~(high)CD127~(low)Tregs在Ⅲ期患者显著高于Ⅰ期患者;CD8~+CD28~(-Tregs)在Ⅱ、Ⅲ期显著高于正常对照,且Ⅱ期高于Ⅰ期,Ⅲ期高于Ⅱ期,逐期递增,而在Ⅰ期与对照组比较无显著差异;CD4~+CD25~(+/high)和CD4~+CD25~(high)CD127~(low)Tregs比率在进展期和稳定期均较对照组升高,但两期之间比较无明显差异,而CD8~+CD28~-Tregs在进展期高于稳定期及对照组,稳定期和对照组间比较无明显差异;CD4~+CD25~(high)Tregs和CD4~+CD25~(high)CD127~(low)Tregs比率与Alb水平均呈负相关.结论:MM患者体内存在CD4~+CD25~+Tregs和CD8~+ CD28~-Tregs异常增加,可能是MM免疫逃逸的一个重要机制,这些变化同临床分期、病情进展及预后存在一定程度相关性.     

Gene Expression Profile Analysis in Human T Lymphocytes from Patients with Down Syndrome

Down Syndrome (DS) is caused by the presence of three copies of the whole human chromosome 21 (HC21) or of a HC21 restricted region; the phenotype is likely to have originated from the altered expression of genes in the HC21. We apply the cDNA microarray method to the study of gene expression in human T lymphocytes with trisomy 21 in comparison to normal cells. Two patients with DS were investigated, along with two normal subjects as a control, all being tested in independent, duplicated cell culture experiments. The most consistent finding was the overexpression of the superoxide dismutase gene (SOD1), located on 21q, and of MHC DR beta 3 (HLA‐DRB3), GABA receptor A gamma 2 (GABRG2), acetyltransferase Coenzyme, A 2 (ACAT2) and ras suppressor protein 1 (RSU1) genes. When the data were clustered according to chromosome localization, the HC21 gene set showed, on average, the highest expression in DS cells in all the experiments. Moreover, separate clustering of patients and controls was obtained when analysis was restricted to HC21 gene expression values. These findings reinforce the specific gene dosage theory for the pathogenesis of the DS phenotype, and show a consistent overexpression of the SOD1 gene on 21q.     

Activation and Coreceptor Expression of T Lymphocytes in HIV/AIDS Patients of China

The objective of this paper was to investigate the activation and coreceptor CCR5, CXCR4 expression of T lymphocytes in HIV/AIDS patients of China, and to study their association with disease progression. Seventy-seven HIV/AIDS patients and thirteen normal controls were enrolled and three-color flow-cytometry was used to detect the activation marker HLA-DR, CD38 and the coreceptor CCR5, CXCR4 expression on T lymphocytes in whole blood samples taken from the patients and the controls. The HLA-DR, CD38 and CCR5 expression on CD4, CD8⁺ T cells in AIDS patients was higher than in asymptomatic HIV-1 infected patients and normal controls (p < 0.05); The activation and CCR5 expression on T lymphocytes significantly correlated with CD4⁺ T lymphocyte number and viral load. The activation on T lymphocytes and the expression of CCR5 on T lymphocytes in HIV/AIDS patients of China are significantly correlated with disease progression.     

CD28 and T cell co-stimulation

Over the last decade the concept of T cell co-stimulation has emerged to take a central role in the process of T cell activation. However, the exact definition of co-stimulation is still unclear. In this review, we re-examine the concept of co-stimulation. We suggest that while co-stimulation is important, there is little evidence to link co-stimulation with T cell anergy. We then suggest a framework for studying co-stimulation. Focusing on recent advances in our understanding of CD28, we discuss four areas of T cell activation where co-stimulation may play a role.     

老年人T细胞膜型CD28及血清中可溶性CD28的表达及其意义

分析老年人(年龄在60岁以上)外周血T细胞膜型CD28(mCD28)及血清中可溶性CD28(sCD28)的表达水平,探讨该分子在老年人免疫功能改变中的意义。分别收集肝素抗凝及不抗凝的老年人外周血,抗凝血经分离获取单个核细胞,间接免疫荧光及流式细胞仪分析,老年人T细胞mCD28的阳性表达率为男性(41.56%±11.23%)及女性(42.97%±12.02%)。与年轻人[男性(61.51%±17.45%)及女性(62.38%±16.22%)]相比,差别具有显著性(P<0.01)。酶联免疫吸附法(ELISA)检测,老年人血清中sCD28的含量为男性(1.08±0.45)及女性(0.98±0.47)ng/ml,与青年人[男性(0.55±0.16)及女性(0.52±0.13)ng/ml]相比,差别具有显著性(P<0.01)。老年人T细胞mCD28的表达水平下降,而血清中sCD28的含量升高。     

A Whole-Blood Assay for Qualitative and Semiquantitative Measurements of CD69 Surface Expression on CD4 and CD8 T Lymphocytes Using Flow Cytometry

A whole-blood flow cytometry-based assay was utilized to assess CD4 and CD8 T-lymphocyte activation in response to phytohemagglutinin (PHA) stimulation. T-lymphocyte activation was assessed by qualitative (percent CD69) and semiquantitative (anti-CD69 antibody binding capacity) measurements of CD69 surface expression. Whole-blood samples from 21 healthy and 21 human immunodeficiency virus (HIV)-infected (<500 absolute CD4 counts per mm³) individuals were stimulated with 20 μg of PHA per ml for 18 to 24 h. The proportions of activated CD4 and CD8 T lymphocytes expressing CD69 (percent CD69) and the levels of CD69 expression on each T-lymphocyte subset (anti-CD69 antibody binding capacity) were measured. By using this assay system, T-lymphocyte activation was impaired in both CD4 and CD8 T-lymphocyte subsets of HIV-infected individuals. The proportions of CD69-positive CD4 and CD8 T lymphocytes were 43 and 27% lower, respectively, in samples from HIV-infected individuals compared to samples from healthy individuals. Similarly, the levels of CD69 expression on each activated CD4 and CD8 T-lymphocyte subset were 48 and 51% lower, respectively. These results suggest that both qualitative and semiquantitative measurements of CD69 surface expression by flow cytometry can be used to assess T-lymphocyte activation.     

Characteristics of Expanded CD4+CD28null T Cells in Patients with Chronic Hepatitis B

Expanded CD4⁺CD28^null T cells have not been described in the circulation of patients with chronic hepatitis B (CHB). The aim of the present was to detect and characterize the surface phenotype and functional capacity of these cells in CHB patients. Expanded CD4⁺CD28^null T cells were detected in the circulation of CHB patients with high viral load and elevated aminotransferase levels. Most CD4⁺CD28^null T cells showed a CD27?CD45RA^?CD45RO⁺ surface phenotype. The markers CD56, CD57 and killer immunoglobulin-like receptor (KIR) were detected on CD4⁺CD28^null T cells, but the majority were positive for CD57. Functionally, CD4⁺CD28^null T cells were found to be potent cytotoxic T lymphocytes with perforin and granzyme B secretion profiles. These findings indicate that the expanded CD4⁺CD28^null T cells are cytotoxic memory T cells and display a distinct functional phenotype in comparison with CD4⁺CD28⁺ T cells. The presence of these cells appears to be associated with inflammatory conditions, suggesting that these elevated CD4⁺CD28^null T cells might be involved in the pathogenesis of CHB.