CD8+ T细胞对HIV-1合成表位的免疫主导应答研究

目的研究CD8^＋ T细胞对人免疫缺陷病毒1型（HIV-1）表位的免疫主导应答。方法分别采用酶联免疫斑点技术（ELtSPOT）和羧乙基锗倍半氧化物（CFSE）标记流式分析技术，以覆盖HIV-1 Env、Pol、Gag、Vif、Nef、Tat区的701个重叠肽段组成的34个肽段库及其部分单肽段作为刺激表位，对一例感染HIV-1的长期不进展者（LTNP）的外周血单个核细胞（PBMC）中CD8^＋ T细胞的了γ-干扰素（IFN-γ）分泌细胞频率和细胞增殖率进行了测定研究。结果HIV-1 Gag区域肽段诱导产生的CD8^＋ T细胞的IFN-γ分泌细胞频率最高，Nef、Tat、Vif区域依次顺减，Env和Pol区域不能诱导产生显著性应答；在IFN-γ ELISPOT实验中，肽段和相应肽段库刺激产生的结果一致；CD8^＋ T细胞在单肽段刺激下，用ELISPOT技术测定的IFN-γ分泌细胞频率和CFSE标记流式分析技术测定的细胞增殖率显示出较好的相关性。结论CD8^＋ T细胞能特异性识别某些HIV-1抗原表位，诱导出免疫主导应答；当进行HIV-1特异性CD8^＋ T细胞反应增殖测定和免疫主导应答研究时，ELISPOT是值得称道的标准实验，同时，推荐一种新颖的CFSE标记流式分析技术。     

Studies on the cross-clade and cross-species conservation of HIV-1 Gag-specific CD8 and CD4 T cell responses elicited by a clade B DNA/MVA vaccine in macaques

Here, we evaluate the T cell responses raised by our HIV-1 clade B DNA/MVA vaccine for recognition of a HIV-1 circulating recombinant form (CRF) AG Gag sequence (CRF-02). The cross-clade activity for the AG sequence was better conserved for CD8 than CD4 T cells. CD8 T cells exhibited 75% conservation for height and 83% conservation for breadth, whereas CD4 responses exhibited 45% conservation for height and 50% conservation for breadth. Five CD8 epitopes and 8 CD4 epitopes were mapped. Three of the 5 CD8 epitopes and 2 of the 8 CD4 epitopes were conserved across multiple HIV-1 clades. Impressively, all of the CD8 epitopes and half of the CD4 epitopes have been reported for human infections. Our results demonstrate that the clade B DNA/MVA HIV vaccine elicits T cell responses against epitopes that are conserved in multiple clades and recognized by humans and macaques.     

HIV-1感染者CD4+T细胞受体基因多样性特点及其与病毒载量的相关性

目的 分析HIV-1感染者CD4+T细胞受体(TCR)基因的多样性特征及其与病毒载量的相关性.方法 应用抗CD4单克隆抗体从25份HIV-1感染者和10份HIV-1阴性对照样本外周血单个核细胞(PBMC)中分离CD4+T细胞,提取细胞总RNA,然后通过逆转录及巢式多聚酶链反应(nestedPCR)对TCR 22个Vβ基因家族的互补决定区3(CDR3)进行扩增,利用ABI3700测序仪对扩增的PCR产物进行扫描,定最分析HIV-1感染者TCRCDR3区多样性变化特征及其与病毒载量的相关性.结果 HIV-1感染者CD4+T细胞TCR CDR3区平均D(distance)值显著高于正常对照组(P＜0 05),TCR Vβ基因各家族CDR3长度谱型成寡克隆分布,TCR CDR3区的紊乱与病毒载量呈正相关(r=0 494,P＜0 05);HIV-1感染引起TCR多样性的改变不仅表现在不同Vβ基因家族上,而且也表现在CDR3长度上,其中感染者Vβ8、Vβ22、Vβ23基因家族的变化与正常人差异有统计学意义.结论 HIV-1感染能引起CD4+T细胞TCR基因多样性的减少及高斯(Gaussian)分布的破坏,TCR CDR3区的紊乱与病毒载量呈正相关.

Abstract：

Objective To assess the impact of the virus on the complementary determining region 3 (CDR3) length diversity of T cell receptor(TCR) Vβ repertoires of CD4+ T lymphocytes and to explore its association with viral load in individuals with HIV-1 infection. Methods The TCR repertoire was examined using spectratyping of CDR3 length diversity within CD4+ T cells in HIV infected and healthy adults. Separation of CD4+ T cells from peripheral blood mononuclear cells ( PBMCs) was carried out by using immunomagnetic beads coated with anti-CD4 antibody. Total RNAs from the purified CD4 + T lymphocytes were isolated and used to perform nested-PCR amplifications in CDR3 of 22 TCR gene families. CDR3 diversity and its association with viral load in individuals with HIV-1 infection were analyzed. Results An average diversity for all CDR3 profiles in CD4+ T cells from 25 HIV-infected individuals was significantly different as compared to 10 age-matched healthy donors (P＜0.05) with the HIV-infected individuals losing diversity in the CDR3 profiles. There was positive correlation between changes in TCR CDR3 diversity and viral load (r = 0. 494, P ＜ 0. 05). The changes in CDR3 length diversity of Vβ families in HIV-infected individuals, particular in Vβ8, Vβ22, Vβ23 were statistically different from the healthy controls. Conclusion HIV-1 infection might induce the loss of TCR Vp repertoire diversity and disrupt the CDR3 Gaussian distributions within CD4 + T cells. There should be positive correlation between changes in TCR CDR3 diversity and the viral load in HIV-1 infected patients.     

Induction of organ-selective CD4+ regulatory T cell homing

Compelling evidence suggests that Foxp3⁺CD25⁺CD4⁺ Treg play a fundamental role in immunoregulation. We have previously demonstrated that Treg have to enter peripheral tissues to suppress ongoing inflammation. However, relatively little is known about how Treg acquire the expression of homing receptors required for tissue‐ or inflammation‐specific migration. Migratory properties of conventional naïve T cells are shaped by the tissue microenvironment and organ‐specific dendritic cells during priming. Here, we show that this basic concept also holds true for CD25⁺CD4⁺ Treg: Priming of Treg within peripheral LN led to the expression of selectin ligands, which facilitate migration into inflamed skin, whereas activation within mesenteric LN led to induction of the integrin α₄β₇, which is required for migration into mucosal tissues. Furthermore, we could establish in vitro culture systems containing either dendritic cells from mesenteric and peripheral LN, or retinoic acid and IL‐12 as polarizing compounds to induce mucosa‐ and skin‐seeking Treg, respectively. Together, our results demonstrate that Treg, similarly to conventional T cells, can be configured with organ‐selective homing properties allowing efficient targeting into distinct tissues.     

中国HIV感染者细胞毒性淋巴细胞与CD4~+CD25~+调节性T细胞相关性研究

目的：对中国HIV感染者NK细胞、CD8^＋T细胞及胞内穿孔素、颗粒酶-B表达与CD4^＋CD25^＋Foxp3^＋调节性T细胞水平的相关性进行研究,探讨调节性T细胞在HIV感染中的作用机制。方法：选取73名HIV/AIDS患者（长期不进展组、无症状HIV组、AIDS组）,应用流式细胞仪胞内染色技术检测NK细胞、CD8^＋T细胞数量及胞内穿孔素、颗粒酶-B表达水平,分析其与CD4^＋CD25^＋Foxp3^＋调节性T细胞水平的相关性。结果：CD4^＋CD25^＋Foxp3^＋调节性T细胞百分率与NK细胞、CD8^＋T淋巴细胞数量呈明显负相关（P〈0.01）,与CD8^＋T细胞内穿孔素、颗粒酶-B表达百分率呈明显正相关（P〈0.05）,与NK细胞内穿孔素、颗粒酶-B表达水平绝对值负相关（P〈0.01）,与CD8＋T细胞内颗粒酶-B表达绝对值呈明显负相关（P〈0.01）,与CD8^＋T细胞内穿孔素表达绝对值无明显相关性（P〉0.05）。CD4^＋CD25^＋Foxp3^＋调节性T细胞绝对值与CD8^＋T细胞内穿孔素、颗粒酶-B表达百分率呈明显负相关（P〈0.05）。结论：中国HIV感染者细胞毒性淋巴细胞数量功能的变化与调节性T细胞显著相关,提示高水平的调节性T细胞可能与细胞毒性淋巴细胞耗竭相关,可能为导致疾病进展的原因之一。     

Human circulating specific antibody-forming cells after systemic and mucosal immunizations: differential homing commitments and cell surface differentiation markers

Circulating spontaneous antibody-secreting cells (ASC) induced by mucosal and systemic immunizations in human volunteers have been characterized with respect to differentiation stage and homing commitments. Irrespective of the immunization route, the large majority of ASC co-expressed CD19 and HLA-DR, which are normally lost during the transition of plasmablasts to plasmocytes, as well as CD38, a marker of activated B cell blasts, expressed also by plasmocytes. However, these cells expressed neither CD28, a molecule acquired by plasmocytes, nor CD22 and CD37, which are lost during the transition of plasmablasts to plasmocytes. Therefore, the large majority of ASC found in peripheral blood after oral and parenteral immunizations are terminally differentiated B cells, but not fully differentiated plasmocytes. As a whole, the mucosally derived ASC population seemed to be more homogenously differentiated. CD25 was detected on few ASC, whereas ASC expressing CD71 were more numerous, especially among systemically derived ASC. Almost all ASC expressed the adhesion molecules CD44 and α4-integrins, irrespective of immunization route. However, virtually all systemically derived ASC expressed L-selectin, recognizing the peripheral lymph node addressin, whereas only a minority of mucosally induced blood ASC expressed L-selectin. These studies are the first to demonstrate in humans that circulating precursors of mucosal B cell immunoblasts utilize organ-specific recognition mechanisms distinct from those of corresponding systemic B cells and appear to be more advanced in the B lineage maturation pathway. Specialization of receptor expression could explain both the unification of immune responses in diverse mucosal sites and the physiologic segregation of mucosal from non-mucosal immune mechanisms in humans.     

Multiple sites of post-activation CD8+ T cell disposal

Antigen-triggered activation of T cells leads to a sequence of differentiation steps including up-regulation of activation markers, blast formation, proliferation, delivery of effector functions, and ultimately apoptosis. It is still controversial in which anatomical site activation-induced apoptosis and elimination of T cells occur. To address this question, we used mice transgenic for a T cell receptor (F5) specific for an influenza virus nucleoprotein peptide (NP68) presented on the major histocompatibility complex H-2 D^b molecule. Accumulation and apoptosis of T cells was studied using terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling in situ combined with immunohistology after intraperitoneal injection of the cognate peptide into F5 mice which are wild type or deficient for Rag-1. After 4 days of peptide treatment, large perivascular infiltrations of CD8⁺ cells were observed in liver, lung, and kidney of F5 mice. CD8⁺ cell numbers were also increased in skin and small intestine, but not in brain or heart muscle of peptide-treated animals. The infiltrating CD8⁺ cells show an increased percentage of apoptosis in liver, lung and, most strikingly, the kidney. These data suggest that in the F5 system, T cell disposal after activation occurs in a number of organs. Essentially identical findings were obtained in Rag-1^+/+ and Rag-1^-/- F5 mice, suggesting that the deletion mechanism did not involve other T or B cells.     

Human CD8+ cytotoxic T cell responses to adenovirus capsid proteins

Adenoviruses (Ads) cause fatal disease in allogeneic stem cell transplant recipients, but there is no established therapy. Ad-specific CD8+ T cells were detected in PBMC from healthy adults at a mean frequency of 77 per 10(5) CD8+ T cells (range 8-260) by interferon-gamma ELISPOT and cytokine flow cytometry assays. CD8+ T cell lines from 7 of 7 donors exhibited MHC-class-I-restricted killing of targets expressing the capsid protein hexon. In contrast, cytotoxicity against the capsid proteins fiber and penton base was weaker or not detected. Two HLA-A2-restricted hexon epitopes and one HLA-B-restricted epitope were identified, all of which are adjacent to or overlap an HLA-DP4-restricted epitope in the highly conserved C-terminus. Thus, hexon is the immunodominant T cell target among capsid proteins and contains multiple C-terminal epitopes conserved among serotypes. These data support evaluation of donor lymphocyte infusions for treatment of Ad disease post-transplant.     

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.     

Preclinical evaluation of cellular immune responses elicited by a polyvalent DNA prime/protein boost HIV-1 vaccine

While DNA vaccines have been shown to prime cellular immune responses, levels are often low in nonhuman primates or humans. Hence, efforts have been directed toward boosting responses by combining DNA with different vaccination modalities. To this end, a polyvalent DNA prime/protein boost vaccine, consisting of codon optimized HIV-1 env (A, B, C, E) and gag (C) and homologous gp120 proteins in QS-21, was evaluated in rhesus macaques and BALB/c mice. Humoral and cellular responses, detected following DNA immunization, were increased following protein boost in macaques and mice. In dissecting cellular immune responses in mice, protein-enhanced responses were found to be mediated by CD4+ and CD8+ T cells with a Th1 cytokine bias. Our study reveals that, in addition to augmenting humoral responses, protein boosting of DNA-primed animals augments cellular immune responses mediated by CD8+ CTL, CD4+ T-helper cells and Th1 cytokines; thus, offering much promise in controlling HIV-1 in vaccinees.     

Concentrations of Soluble CD95 and CD8 Antigens in the Plasma and Levels of CD8+CD95+, CD8+CD38+, and CD4+CD95+ T Cells Are Markers for HIV-1 Infection and Clinical Status

Apoptosis mediated via the CD95 (FAS/APO-1) receptor is thought to play a role in the depletion of CD4+ T cells in HIV infection. In the present study expression of the CD95 antigen on lymphocyte subsets and the plasma level of soluble CD95 (sCD95) were determined in HIV-1-infected adults. The expression of CD95 was increased on CD8 cells in all groups of HIV+ individuals, while increased expression of CD95+ cells on CD4 cells was limited to individuals with CD4 counts of <200 mm³. The proportion of CD4+ that expressed CD95 was inversely correlated with the percentage of CD4+ PBL. The concentration of sCD95 was significantly higher in the plasma of HIV-infected individuals than in normal controls. The level of sCD95 in HIV-infected subjects showed no correlation with the percentage of PBL expressing CD95, indicating that the increased level of sCD95 did not reflect release from CD95+ PBL. The plasma sCD95 concentration was significantly correlated with the percentage of CD8+ cells and, particularly, with CD8+CD38– cells. A striking inverse correlation was found between the sCD95 plasma concentration and the proportion of CD4+CD95+ cells out of the total CD4+ population. There was no correlation between the serum level of sCD95 and that of soluble CD8 (sCD8), both of which were increased in the plasma of HIV+ individuals. Unlike the level of sCD95, the level of sCD8 in the plasma of HIV+ individuals. Unlike the level of sCD95, the level of sCD8 in the plasma of HIV+ individuals was correlated with the percentage of CD95+ and CD8+CD38+ cells. The present study indicates that plasma sCD95 may be one of the factors that regulate apoptotic death of lymphocytes in HIV infection.     

T cell receptor cross-recognition of an HIV-1 CD8+ T cell epitope presented by closely related alleles from the HLA-A3 superfamily

HLA-A3 and -A11 share similar peptide-binding motifs, however, it is unclear if promiscuous epitope presentation by HLA-A3 or HLA-A11 is associated with promiscuous TCR recognition. Here, we show that despite widespread cross-presentation of identical HIV-1 peptides in HIV-1-infected individuals expressing HLA-A3 or HLA-A11, peptides presented by HLA-A3 or HLA-A11 commonly exhibited clear immune distinctiveness with exclusive TCR recognition. Yet, using HLA-A3 and HLA-A11 tetramers for testing T cell cross-recognition of the HIV-1 Nef QK10 epitope, we observed in two study persons that specific CD8+ T cell populations were able to cross-recognize this peptide in the context of both HLA-A3 and HLA-A11. This cross-recognition was mediated by single cross-reactive TCRs, as shown by TCR sequencing in conjunction with TCR Vbeta chain immunostaining. In each cross-reactive cell population, multiple TCR beta chain variants were detected in the presence of only one TCR alpha chain variant. Thus, despite distinct TCR recognition of HLA-A3 or HLA-A11 presented HIV-1 peptides in the vast majority of cases, specific TCRs can cross-recognize their antigen in the context of both HLA-A3 and HLA-A11.     

Significantly skewed memory CD8+ T cell subsets in HIV-1 infected infants during the first year of life

HIV-1 infection causes a severe T cell compromise; however, little is known about changes in naive, memory, effector and senescent T cell subsets during the first year of life.T cell subsets were studied over the first year of life in blood from 3 infant cohorts: untreated HIV-infected, HIV-exposed but uninfected, and HIV-unexposed. In HIV-infected infants, the frequency of CCR7⁺CD45RA⁺ naive CD8⁺ T cells was significantly decreased, while the frequency of CCR7⁻CD45RA⁻ effector memory CD8⁺ T cells was increased, compared with the control cohorts. A larger population of CD8⁺ T cells in HIV-infected infants displayed a phenotype consistent with senescence. Differences in CD4⁺ T cell subset frequencies were less pronounced, and no significant differences were observed between exposed and unexposed HIV-uninfected infants. We concluded that the proportion of naive, memory, effector and senescent CD8⁺ T cells during the first year of life is significantly altered by HIV-1 infection.     

Persistent human immunodeficiency virus-1 antigenaemia affects the expression of interleukin-7Ralpha on central and effector memory CD4+ and CD8+ T cell subsets

Interleukin (IL)-7 and its receptor (IL-7Ralpha) play important roles in regulating lymphopoiesis. Previous studies have reported that human immunodeficiency virus-1 (HIV-1) viraemia affects the expression of IL-7Ralpha, but its effects on CD4+ and CD8+ T cell memory subsets have not been studied. Using eight-colour flow cytometry, we compared the immunophenotypic patterns of CD4+ and CD8+ T cell subsets expressing IL-7Ralpha and activation markers, as well as circulating IL-7 levels, in three well-defined groups of HIV-1-infected subjects: successfully treated, viraemic and long-term non-progressor (LTNP). Compared with successfully treated and LTNP subjects, viraemic patients had reduced expression of IL-7Ralpha on both CD4+ and CD8+ T cells, particularly on central and effector memory T cell compartments, and substantially elevated expression of activation markers on CD8+ T cell subsets. Circulating IL-7 levels were correlated negatively with the number of CD4+ and CD8+ T cell subsets expressing IL-7Ralpha; these associations were stronger with CD4+ T cell subsets and mainly with central and effector memory cells. The expression of activation markers on CD4+ and CD8+ cell T subsets was not related to circulating IL-7 levels. A strong negative correlation was observed between central memory CD4+ or CD8+ T cells expressing IL-7Ralpha and those expressing activation markers, independently of IL-7 levels. Collectively, these results provide further insight on the role of unsuppressed viral load in disrupting the IL-7/IL-7Ralpha system and contributing to HIV-1 disease progression.     

中国HIV感染长期不进展者CD4+CD25+Foxp3+调节性T细胞变化研究

目的 对中国HIV感染长期不进展者(LTNP)CD4+CD25+Foxp3+调节性T细胞水平及其与疾病进展相关性进行研究,探讨CD4+CD25+Foxp3+ 调节性T细胞在LTNP保护机制中发挥的作用.方法 选取74名HIV-1感染者(LTNP、典型进展HIV组、AIDS组)及16名健康对照,应用流式细胞仪胞内染色技术在单细胞水平检测CD4+CD25+Foxp3+调节性T细胞表达水平,分析其与CD4+ T细胞数量、病毒载量、淋巴细胞活化、凋亡水平的相关性.结果 中国HIV感染LTNP CD4+CD25+Foxp3+ T细胞百分率明显低于典型进展HIV、AIDS组及健康对照组(P<0.05).HIV/AIDS患者CD4+CD25+Foxp3+ T细胞百分率与CD4+ T细胞显著负相关(r=-0.509,P<0.001),与病毒载量明显正相关(r=0.414,P<0.01),与CD4、CD8+ T细胞表面CD38、CD95表达水平明显正相关(P<0.05),与CD4、CD8+ T细胞表面HLA-DR表达无显著相关性.结论 中国HIV感染LTNP CD4+CD25+Foxp3+ 调节性T细胞百分率明显低于典型进展者,提示调节性T细胞与LTNP保护机制相关.     

CD8+ T cells and immunoregulatory networks in asthma

It is well established that infection with respiratory viruses can cause acute local inflammation in humans and is a leading cause in the hospitalization of asthmatics. Less well recognized is the potential for viral infections to actually protect against the development of asthma, as are the cellular mechanisms which might underlie such protection. This review outlines the basic immunological pathways involved in atopic asthma and details the currently recognized cellular mechanisms induced by respiratory viral infections which can protect against the development of asthma. Specifically, it appears that virus infection induced memory T cells that remain in tissues, e.g. the lung and airways, can under certain circumstances create a local cytokine milieu which inhibits the development of ensuing allergic immune responses at that site. One key aspect of this immune modulation is the cytokine-dependent communication which occurs between the innate and the adaptive immune systems. The mechanistic principles underlying this form of immunomodulation should be taken into consideration when developing future forms of therapy and rational vaccine design.     

Altered primary CD8+ T cell response to a modified virus Ankara(MVA)-vectored vaccine in the absence of CD4+ T cell help

T cell receptor-transgenic F5 mice were used to assess primary CD8+ T cell responses to a modified virus Ankara (MVA)-vectored vaccine in the absence of CD4+ T cell help. Naive, CD8-enriched, CFSE-labelled F5 cells were transferred into normal or CD4+ cell-depleted mice and the mice were vaccinated with MVA.HIVA-NP. At different time points during the primary response, F5 cells were re-isolated and analysed on divisional basis for a number of parameters. We demonstrated that the primary CD8+ T cell response in the absence of CD4+ T cell help differed from that in normal CD4+ cell-undepleted mice. While in the absence of CD4+ T cell help, the initial migratory progress from the local response to a systemic one was not grossly affected, the proportion of dying F5 cells during the expansion phase was markedly increased and resulted in an overall smaller expansion and significantly decreased frequency of CD8+ T cell memory after contraction. T cells primed without help displayed accelerated proliferation and activation, while expression of interferon-gamma remained similar. These phenomena were observed in the lymph nodes draining the MVA.HIVA-NP immunization site and were similar, but delayed by 2-3 days in spleen and non-draining lymph nodes.     

C-type lectin Mermaid inhibits dendritic cell mediated HIV-1 transmission to CD4+ T cells

Dendritic cells (DCs) are important in HIV-1 transmission; DCs capture invading HIV-1 through the interaction of the gp120 oligosaccharides with the C-type lectin DC-SIGN and migrate to the lymphoid tissues where HIV-1 is transmitted to T cells. Thus, the HIV-1 envelope glycoprotein gp120 is an attractive target to prevent interactions with DCs and subsequent viral transmission. Here, we have investigated whether the structural homologue of DC-SIGN, the nematode C-type lectin Mermaid can be used to prevent HIV-1 transmission by DCs. Our data demonstrate that Mermaid interacts with high mannose structures present on HIV-1 gp120 and thereby inhibits HIV-1 binding to DC-SIGN on DCs. Moreover, Mermaid inhibits DC-SIGN-mediated HIV-1 transmission from DC to T cells. We have identified Mermaid as a non-cytotoxic agent that shares the glycan specificity with DC-SIGN and inhibits DC-SIGN-gp120 interaction. The results are important for the anti-HIV-1 microbicide development directed at preventing DC-HIV-1 interactions.     

Phenotypical and functional evaluation of CD8+/S6F1+ T lymphocytes in haemophiliac individuals with HIV-1 infection.

In this study we investigated the distribution of the S6F1 antigen, an epitope of the lymphocyte function-associated antigen, on CD8+ T lymphocytes in a series of 15 HIV-1+ and 20 HIV-1- haemophiliac patients. MoAbs recognizing the S6F1 antigen have been claimed to distinguish between killer effectors (brightly S6F1+ stained) and suppressor cells (dimly S6F1+ stained) within the CD8+ lymphoid population. In addition, we tried to find a correlation between the spontaneous in vitro immunoglobulin synthesis from patients' peripheral blood lymphocytes and the pattern of S6F1 expression. Although the total number of double-positive CD8+/S6F1+ cells was similar in both HIV-1+ and HIV-1- haemophiliac patients, a significant increase in the CD8+/S6F1+ population bright versus dim was documented in HIV-1-infected with respect to HIV-1- haemophiliacs (bright/dim ratio 3.97 +/- 0.61 versus 0.75 +/- 0.1, respectively, P < 0.005). This finding was correlated to a significant increase in spontaneous in vitro immunoglobulin production in HIV-1+ subjects compared with control haemophiliacs (P < 0.005). Purified CD8+ lymphocytes from HIV-1+ subjects showed a reduced suppressor activity on mitogen-induced immunoglobulin production. Taken together, these data suggest that HIV-1 infection favours the generation of CD8+/S6F1+ bright cells with putative cytotoxic-associated function, leading to a progressive reduction in the number of CD8+/S6F1+ dim suppressor lymphocytes. This phenomenon may contribute to the polyclonal hypergammaglobulinaemia present in HIV-1+ haemophiliac patients.