Long-term Nonprogressors Group Research Articles

Identification of miRNA-mRNA crosstalk in CD4+ T cells during HIV-1 infection by integrating transcriptome analyses

BackgroundHIV-1-infected long-term nonprogressors (LTNPs) are characterized by infection with HIV-1 more than 7–10 years, but keeping high CD4+ T cell counts and low viral load in the absence of antiretroviral treatment, while loss of CD4+ T cells and high viral load were observed in the most of HIV-1-infected individuals with chronic progressors (CPs) However, the mechanisms of different clinical outcomes in HIV-1 infection needs to be further resolved.MethodsTo identify microRNAs (miRNAs) and their target genes related to distinct clinical outcomes in HIV-1 infection, we performed the integrative transcriptome analyses in two series GSE24022 and GSE6740 by GEO2R, R, TargetScan, miRDB, and Cytoscape softwares. The functional pathways of these differentially expressed miRNAs (DEMs) targeting genes were further analyzed with DAVID.ResultsWe identified that 7 and 19 DEMs in CD4+ T cells of LTNPs and CPs, respectively, compared with uninfected controls (UCs), but only miR-630 was higher in CPs than that in LTNPs. Further, 478 and 799 differentially expressed genes (DEGs) were identified in the group of LTNPs and CPs, respectively, compared with UCs. Compared to CPs, four hundred and twenty-four DEGs were identified in LTNPs. Functional pathway analyses revealed that a close connection with miRNA-mRNA in HIV-1 infection that DEGs were involved in response to virus and immune system process, and RIG-I-like receptor signaling pathway, whose DEMs or DEGs will be novel biomarkers for prediction of clinical outcomes and therapeutic targets for HIV-1.ConclusionsIntegrative transcriptome analyses showed that distinct transcriptional profiles in CD4+ T cells are associated with different clinical outcomes during HIV-1 infection, and we identified a circulating miR-630 with potential to predict disease progression, which is necessary to further confirm our findings in the future.

KIR3DS1/L1 and HLA-Bw4-80I are associated with HIV disease progression among HIV typical progressors and long-term nonprogressors

BackgroundNatural killer (NK) cells have emerged as pivotal players in innate immunity, especially in the defense against viral infections and tumors. Killer immunoglobulin-like receptors (KIRs) – an important recognition receptor expressed on the surface of NK cells – regulate the inhibition and/or activation of NK cells after interacting with human leukocyte antigen (HLA) class I ligands. Various KIR genes might impact the prognosis of many different diseases. The implications of KIR-HLA interaction in HIV disease progression remains poorly understood.MethodsHere, we studied KIR genotypes, mRNA levels, HLA genotypes, CD4+ T cell counts and viral loads in our cohort of Human Immunodeficiency Virus (HIV)-infected individuals, a group that includes HIV long-term nonprogressors (LTNPs) and typical progressors (TPs).ResultsWe found that the frequency of KIR3DS1/L1 heterozygotes with HLA-Bw4-80I gene was much higher in LTNPs than in TPs (P = 0.001) and that the KIR3DL1 homozygotes without HLA-Bw4-80I gene had higher viral loads and lower CD4+ T cell counts (P = 0.014 and P = 0.021, respectively). Our study also confirmed that homozygosity for the HLA-Bw6 allele was associated with rapid disease progression. In addition to the aforementioned results on the DNA level, we observed that higher level expression of KIR3DS1 mRNA was in LTNP group, and that higher level expression of KIR3DL1 mRNA was in TP group.ConclusionsOur data suggest that different KIR-HLA genotypes and different levels of transcripts associate with HIV disease progression.

Impact of Human Immunodeficiency Virus Infection on Measures of Cardiovascular Disease in Long-Term Nonprogressors

Background Human immunodeficiency virus (HIV)-positive patients are at increased risk of accelerated atherosclerosis and cardiovascular disease (CVD) progression. However, it remains unclear whether this is the result of antiretroviral therapy, CVD risk factors, viral infection, systemic inflammation, or a combination of these elements. This study evaluated the effects of untreated HIV on carotid intimal-medial thickening (cIMT) and serum levels of selected inflammatory markers (IMs), known measures of CVD progression. Methods A cross-sectional case-control study was performed in HIV-infected long-term nonprogressors (LTNPs), with a HIV-negative control group matched by age, race, and sex. Clinical data, lipid profile, CD4 cell counts, HIV-1 RNA levels, cIMT at 3 different locations, and serum levels of different IMs were recorded. Cardiovascular disease risk factors, cIMT, and IMs were statistically compared between the LTNP and HIV-negative groups. Results Thirty-two subjects were enrolled (16 LTNP and 16 controls), and no significant difference in CVD risk factors was found. There was significantly increased cIMT at the carotid bulb for the LTNP group (P Conclusions For the LTNPs, cIMT at the bulb and serum levels of soluble tumor necrosis factor II were significantly greater than the controls, and soluble vascular adhesion molecule-1 significantly correlated with bulb cIMT. This study emphasizes the role of viremia in promoting CVD among HIV-positive patients, likely through inducing systemic inflammation.

Transcriptome analysis of primary monocytes shows global down-regulation of genetic networks in HIV viremic patients versus long-term non-progressors

Despite significant contributions of monocytes to HIV persistence, the genomic basis of HIV-infection of monocytes and its association with plasma viremia remain elusive. To understand HIV interactions with monocytes during disease progression, monocytic transcriptomes from long-term non-progressors (LTNP), HIV+ patients with viral load <1000, with viral load>1000, and seronegative controls were analyzed using Illumina microarray. Differentially expressed genes were identified (fold change >2; adjusted p<0.05) and GSEA between HIV+ groups demonstrated that the down-regulation of the pathways including Toll-like receptor (TLR) signaling, cytokine–cytokine receptor interaction, cell cycle and apoptosis was significantly associated with the viremic groups, whereas their up-regulation with the LTNP group. The down-regulation of TLR pathway in the viremic patients was exemplified by the decreased expression of TLR with the subsequent tuning down of MAPK, NF-κB, JAK-STAT, and IRF cascades. These data provide the first transcriptomic distinction between HIV+ progressors and LTNPs based on primary monocytes.

The activation and dynamics of cytokine expression by CD4+ T cells and AIDS progression in HIV-1-infected Chinese individuals

CD4+ T cells are the main targets of HIV-1 and play a central role during the progression of AIDS, but the mechanism has not been clearly elucidated. In the present study, blood samples were collected from HIV-1-infected Chinese individuals, including typical progressors (TPs) and long-term nonprogressors (LTNPs). More HIV-1 productively infected CD4+ T cells were obtained through co-cultures and the infected CD4+ T cells were discriminated from bystander cells by intracellular p24 staining. The activation level and dynamics of cytokine expression of CD4+ T cells were analyzed. After stimulating the freshly isolated PBMCs with PHA, the frequencies of CD69+CD4+ T cells/CD25+CD4+ T cells were higher in TP than in LTNP group and were positively correlated with viral load and negatively correlated with CD4+ T cell counts. The activation level of CD4+ T cells in the co-cultured PBMCs was higher in TP than in LTNP group, and HIV-1 productively infected CD4+ T cells were more activated than bystander CD4+ T cells. The expression of Th1 cytokines (IL-2 and IFN-γ) and the frequency of Th1 cells in co-cultured PBMCs were lower in TP than in LTNP group. HIV-1 productively infected CD4+ T cells expressed higher level of Th1/Th2 cytokines than bystander cells. More productive HIV-1 infection occurred in Th1 than in Th2 cells, followed by Th0 cells. The present results suggest that the excessive activation level of CD4+ T cells and the preferential replication of HIV-1 in Th1 cells that lead to the shift of Th1 to Th2 are likely crucial to AIDS progression in HIV-1-infected Chinese individuals.

Characteristics of DC subsets in chronic HIV-1 infected patients during antiretroviral therapy

Objective To understand the dynamics of DC subsets in chronic HIV-infected patients during antiretroviral therapy (ART).Methods Seventeen treatment-naive chronic HIV-infected patients were enrolled in our study,and blood was collected at week 0,4,12,24,48 and 60 of ART.Additional 15 HIV-uninfected age-matched healthy adults and 15 long term non-progressors(LTNP) were recruited as controls.CD4+T cell counts and viral loads were examined routinely.The counts of DC subsets were measured by flow cytometry and IFN-α plasma levels were measured by ELISA.Data analysis was performed using SPSS version 16.0.Results ( 1 ) Before ART,mDC ( percentage and absolute count) in ⅢⅤ-infected group were significantly lower than those in healthy group and LTNP group,P＜0.001 in both groups.After 60 weeks of ART,mDC in HIV-infeeted group were significantly increased,and there were no significant differences compared with healthy controls and LTNP group.(2) pDC and IFN-α plasma levels remained relatively stable during ART,and similar to those in healthy controls and LTNP group.(3)Significant associations were found for DC subsets and CD4+ T cell counts before ART.mDC subsets at week 12,24,60 post ART were positively correlated with CD4+ T cell counts,and negntively correlated with virus load.Changes in mDC at week 8 post ART positively correlated with the changes in CD4+T cells at week 60 post ART,and negatively correlated with the changes in virus load at week 60 post ART.Conclusion The counts of mDC significantly reduced in HIV-infected patients,increased after ART,and positively correlated with CD4+ T cell counts.The findings suggest that mDC may play an important role in controlling HIV infection,mDC may serve as an early predictor for immune reconstitution in the initiation of ART. Key words: Human immunodeficiency virus infection; Antiretroviral therapy; Dendritic cell; Interferon

Trivalent Adenovirus Type 5 HIV Recombinant Vaccine Primes for Modest Cytotoxic Capacity That Is Greatest in Humans with Protective HLA Class I Alleles

If future HIV vaccine design strategies are to succeed, improved understanding of the mechanisms underlying protection from infection or immune control over HIV replication remains essential. Increased cytotoxic capacity of HIV-specific CD8+ T-cells associated with efficient elimination of HIV-infected CD4+ T-cell targets has been shown to distinguish long-term nonprogressors (LTNP), patients with durable control over HIV replication, from those experiencing progressive disease. Here, measurements of granzyme B target cell activity and HIV-1-infected CD4+ T-cell elimination were applied for the first time to identify antiviral activities in recipients of a replication incompetent adenovirus serotype 5 (Ad5) HIV-1 recombinant vaccine and were compared with HIV-negative individuals and chronically infected patients, including a group of LTNP. We observed readily detectable HIV-specific CD8+ T-cell recall cytotoxic responses in vaccinees at a median of 331 days following the last immunization. The magnitude of these responses was not related to the number of vaccinations, nor did it correlate with the percentages of cytokine-secreting T-cells determined by ICS assays. Although the recall cytotoxic capacity of the CD8+ T-cells of the vaccinee group was significantly less than that of LTNP and overlapped with that of progressors, we observed significantly higher cytotoxic responses in vaccine recipients carrying the HLA class I alleles B*27, B*57 or B*58, which have been associated with immune control over HIV replication in chronic infection. These findings suggest protective HLA class I alleles might lead to better outcomes in both chronic infection and following immunization due to more efficient priming of HIV-specific CD8+ T-cell cytotoxic responses.

C-Reactive Protein Levels Increase During HIV-1 Disease Progression in Rakai, Uganda, Despite the Absence of Microbial Translocation

Microbial translocation has been implicated as a contributing factor to the heightened immune activation observed during HIV-1 disease progression. When examined in a longitudinal study of HIV-1 seroconverters in Rakai, Uganda, microbial translocation was not associated with HIV-1 disease progression. However, the role of general immune activation in HIV disease progression in this population was not fully examined. Longitudinal serum samples of HIV-1 seroconverters in three HIV-1 disease progression groups [long-term nonprogressors (LTNP), standard progressors (SP), and rapid progressors (RP)] from Rakai, Uganda, were tested for levels of C-reactive protein (CRP), a marker for immune activation. CRP levels significantly increased in the SP group (P < 0.0001) but not in the RP group or the LTNP group. CRP levels during the first year post-HIV seroconversion in the RP group were significantly higher than those observed in the LTNP group (P < 0.05). For the entire population, CRP levels negatively correlated with lipopolysaccharide levels (P < 0.05) and were not associated with endotoxin antibody levels. This study suggests that in this population, increased immune activation is significantly associated with HIV-1 disease progression but not microbial translocation.

HIV-specific CD8+ T cell responses to HXB2 Gag and Nef peptide pools in Chinese HIV/AIDS patients

HXB2 is primarily used as a template strain in developing HIV vaccines in Europe and the US. However, it is not yet known whether the strain can induce strong HIV-specific CD8+ T cell responses in Chinese HIV/AIDS patients. In the present study, two groups of subjects were investigated: 9 AIDS patients and 7 long-term nonprogressors (LTNPs). HIV-specific CD8+ T cell responses were examined in all patients through the ELISPOT assay. CD4+ T cell counts, CD8+ T cell counts, viral load and HIV subtype of each patient were also measured. Thailand B virus strain was identified among all the patients. The breadth and magnitude of HIV-specific CD8+ T cell responses in the LTNPs group are greater than those in the AIDS group (P<0.01). There is a positive correlation between magnitude of HIV-specific CD8+ T cell responses and CD4+ T cells, and a negative correlation between HIV-specific CD8+ T cell responses and mean viral load. In summary, the HIV-specific CD8+ T cell responses to the HXB2 Gag and Nef peptide pools are considerable in Chinese HIV/AIDS patients infected with Thailand B virus strain. HIV-1 vaccines based on HXB2 strain that can induce extensive immunity may be helpful for Chinese.

Nef Mutations in Long-term Non-progressors from Former Plasma Donors Infected with HIV-1 Subtype B in China

To study the specific amino acid variation in Nef that may be related to disease progression after infection with HIV-1 subtype B, a predominant strain circulating in China, and to determine whether changes in Nef secondary structure may influence different stages of AIDS development based on the concept that the Nef gene of HIV infection dramatically alter the severity of viral infection and virus replication and disease progression, and that long-term non-progressors (LTNP) of HIV infection are commonly associated with either a deletion of the Nef gene or the defective Nef alleles. The study subjects were divided into LTNP1(n=14), LTNP2 (n=16) and slow progressor (SP, n=19) groups for mutational analysis of the Nef sequence. The data were obtained by using Bioedit, MEGA, Anthewin and SAS software. Residues in Nef TA(48/49) and K151 occurred more frequently in the LTNP group while AA(48/49) was more frequently observed in the SP group. Of the differences observed in the secondary structure comparison using Nef consensus sequences of these three groups, one was roughly corresponding to the Nef(48/49) mutation site. TA(48/49), K(151), and AA(48/49) in the Nef gene might be associated with the different stages of HIV infection, and there may be a link between the Nef secondary structure and the progression of HIV-1 infection.

Correlation between the function of monocytes/macrophages and disease progression in people living with HIV/AIDS in several provinces in China

To investigate the functional states of peripheral blood monocytes/macrophages and their relation with the disease progression in people living with HIV/AIDS (PWHA). Peripheral blood samples were collected from 57 PWHA who didn't receive antivirus treatment before and 32 healthy controls in Jilin, Liaoning, and Henan provinces. Flow cytometry was used to detect the expression of the early activation molecule CD69 in the CD14(+) cells. The plasma HIV RNA level was determined using real-time PCR. The CD69 expression rate in the CD14(+) T cells of the PWHA group was 27% +/- 4%, significantly higher than that of the controls (P < 0.01). The CD69 expression rate of the AIDS group was 39% +/- 3%, significantly higher than those of the HIV group and long-term nonprogressors (LTNP) group (26% +/- 3% and 20% +/- 4% respectively, both P < 0.05), that of the HIV groups being significantly higher than that of the LTNP group too (P < 0.05). The side scatter value of the CD14(+) T cells of the PWHA group was 76 +/- 16, significantly higher than that of the control group (50 +/- 12, P < 0.05). The monocyte/macrophage CD69 expression rate was significantly negatively correlated with the absolute value of CD4(+) T cells (r = -0.872, P < 0.01), and not correlated with the value of CD8(+) T cells (P > 0.05). The monocyte/macrophage CD69 expression rate was significantly positively correlated with the HIV-1 RNA viral load (r = 0.697, P < 0.01). The activation and the phagocytosis function of the monocytes/macrophages of the PWHA in China are higher than those of the healthy control. They are positively correlated with the disease progression.

HIV-1-Infected Long-Term Non-Progressors have Milder Mitochondrial Impairment and Lower Mitochondrially-Driven Apoptosis in Peripheral Blood Mononuclear Cells than Typical Progressors

Mitochondrial parameters in peripheral blood mononuclear cells (PBMC) and their relationship with mitochondrially-driven PBMC apoptosis were investigated in a group of HIV-1-infected long-term nonprogressors (LTNP) and compared with untreated asymptomatic HIV-1 infected typical progressors (TP) and uninfected healthy controls (HC). Twenty-six LTNP, 27 TP and 31 HC were evaluated. Studies were performed in PBMCs. Mitochondrial DNA content (mtDNA) was assessed by quantitative real-time PCR. Activities of mitochondrial respiratory chain complexes (MRC) II, III and IV were determined by spectrophotometry. Caspase-3 activity was assessed by fluorimetry, and caspase-9 activation and Bcl-2 levels were assessed by immunoblotting. mtDNA abundance (p<0.05), MRC complex II (p<0.001), complex III (p<0.01) and complex IV (p=0.01) were lower in the TP group than in the HC group. In the LTNP group these parameters were similar to those of the HC group except for complex II, which was decreased (p<0.01). The PBMC of TP showed the highest overall apoptotic activation, since their caspase-3 activity was greater than that of HC (p<0.05) and LTNP. In the case of LTNP, however, the difference was non-significant. Caspase-9 and the caspase-9/Bcl-2 ratio were both over-expressed in TP compared to HC (p<0.01) and LTNP (p<0.05). Both of these measurements indicate that mitochondrially-driven apoptosis in TP is greater than in LTNP and HC. A relationship between mitochondrial damage and apoptotic activation was found in TP. Mitochondrial damage is associated with increased PBMC apoptosis in patients with active HIV-1 replication (TP). These abnormalities are slight or not present in LTNP.

High Frequencies of the CCR2b-64I and SDF1-3'A Mutations with HIV Infection in Koreans

Background: Host genetic polymorphisms in the HIV-1 co-receptor CCR5 and CCR2b and SDF-1, ligand for co-receptor CXCR4, have been known to be associated with the resistance of HIV infection and/or the delayed disease progression in HIV-infected patients. Methods: We examined the frequencies of SDF1-3’A and CCR2b-64I alleles of 354 Koreans including 100 HIV-uninfected persons, 13 discordant spouses of HIV-infected persons, and 241 HIV-infected persons. The genotyping assays of SDF1 and CCR2b genes were carried out by polymerase chain reaction-restriction fragment length polymorphism. Results: The frequencies of CCR2b-64I and SDF1-3’A alleles in Koreans were very high compared with Caucasians and blacks. Observed frequencies of CCR2b-64I and SDF1-3’A allelic variants were 25.1% and 28.7%, respectively. The frequency of the CCR2b-64I allele in Koreans was 2~4 times higher than those of other ethnic groups with the exception of Asian. The frequencies of CCR2b-64I and SDF13’A genotypes did not show the significant difference between HIV-infected and uninfected Koreans. However, the prevalence of CCR2b-64I genotype of the LTNP group was about two times higher than that of the remainder group (P< 0.05). Four (45%) out of 9 LTNPs (long-term nonprogressors) showed having the SDF1-3’A allele and 7 (78%) out of 9 LTNPs carried the CCR2b-64I allele. 3 (33%) out of 9 LTNPs had both SDF1-3’A and CCR2b-64I alleles. But none of 5 RPs (rapid progressors) appeared to have both SDF1-3’A and CCR2b-64I alleles. Conclusion: The different genetic backgrounds in study populations may affect the disease progression and the AIDS epidemic in each country. Further studies need to define whether high frequencies of CCR2b-64I and SDF1-3’A allelic variants may affect the HIV disease progression. (Immune Network 2002;2(2):86-90)

Frequency and function of HIV-specific CD8 + T Cells

The virus-specific CD8 + T cell responses of 27 HIV-infected patients were studied, including a unique cohort of long term nonprogressors (LTNP) with normal CD4 + T cell counts, low levels of plasma viral RNA, strong proliferative responses to HIV antigens and an over-representation of the HLA B*5701 class I allele. The frequencies of CD8 + T cells specific to the majority of HIV gene products were measured by flow cytometric detection of intracellular interferon-gamma (IFN-γ) in response to HIV-vaccinia recombinant infected autologous B cells. Very high frequencies (1.4–22%) of circulating CD8 + T cells were found to be HIV-specific and were not only found in LTNP with reduced plasma virus. No correlation was evident between the frequency of HIV-specific CD8 + T cells and levels of plasma viremia. In each case, the vast majority of cells (up to 17.2%) responded to Gag– Pol gene products. Although similar frequencies of Gag peptide-specific CD8 + T cells were found in LTNP and progressors by either intracellular IFN-γ or MHC class I tetramer staining, the breadth of these responses was greater in patients with progressive HIV infection compared with the LTNP group. The frequency of CD8 + T cells specific for a single peptide was not representative of an individual patient's total HIV-specific CD8 + T cell response. These data demonstrate that high numbers of HIV-specific CD8 + T cells exist even in patients with high level viremia and progressive disease. Further, they suggest that other qualitative parameters of the CD8 + T cell response may differentiate some patients with very low levels of plasma virus and nonprogressive infection.

Heterophile Antibodies Indicate Progression of Autoimmunity in Human Type 1 Diabetes Mellitus Before Clinical Onset

We previously reported serum cytokines in a group of long term non-progressors to Type 1 diabetes; this reactivity detected in ELISA is now identified as heterophile antibody in some sera. Here, we characterize heterophile antibody activity. A 14 kDa-polypeptide from heterophile antibody containing serum bound to an anti-IL-4 column, but IL-4 was not detected by Western blot or by MS/MS sequencing. However, in 2/13 heterophile antibody positive sera, T-cell growth was potentiated and was blocked by an anti-human immunoglobulin. To examine the relationship between low affinity heterophile antibody presence and disease progression, 1100 archived serum samples were analyzed with two pairs of antibodies from 443 diabetes-free first degree relatives of Type 1 diabetes mellitus patients for heterophile antibody; 95 individuals developed diabetes on follow-up. Twenty-two individuals, whose serum was heterophile antibody positive with the second pair of antibodies (but negative with the first pair of antibodies), had a significantly higher incidence of developing diabetes after five years. Thirty-seven individuals with heterophile antibody reactivity with the first pair of antibodies, regardless of reactivity with the second pair of antibodies, had a significantly lower incidence of developing diabetes. While we cannot exclude the presence of genuine cytokine in all sera, these data indicate the presence of distinct groups of heterophile antibodies in patients at high risk to develop diabetes. Thus, anti-Ig heterophilic antibodies with different immunochemical reactivities are linked to the progression of or protection from Type 1 diabetes autoimmunity.

HLA B*5701 is highly associated with restriction of virus replication in a subgroup of HIV-infected long term nonprogressors.

A unique cohort of HIV-1-infected long term nonprogressors (LTNP) with normal CD4(+) T cell counts and <50 copies/ml of plasma were prospectively recruited for study. HLA typing revealed a dramatic association between the HLA B*5701 class I allele and nonprogressive infection [85% (11 of 13) vs. 9.5% (19 of 200) in progressors; P < 0. 001]. Antigen-specific CD8(+) T cells were enumerated by flow cytometric detection of intracellular IFN-gamma in response to HIV antigens and HLA B*57-gag tetramer staining. No quantitative differences in the total HIV-specific CD8(+) T cell responses were observed between B*57(+) LTNP and five B*57(+) progressors (P = 0.4). Although similar frequencies of peptide specific CD8(+) T cells were also found, the gag-specific CD8(+) T cell response in the LTNP group was highly focused on peptides previously shown to be B*57-restricted. These findings indicate that, within this phenotypically and genotypically distinct cohort, a host immune factor is highly associated with restriction of virus replication and nonprogressive disease. They also strongly suggest a mechanism of virus specific immunity that directly operates through the B*5701 molecule. Further characterization of qualitative differences in the virus-specific responses that distinguish HLA B*57(+) LTNP from progressors may ultimately define mechanisms of effective immune mediated restriction of virus replication.

Low CD4 counts rather than superantigenic-like effects account for differences in expressed T-cell receptor (TCR) repertoires between HIV-1 seropositive long-term non-progressors and individuals with progressive disease.

Analysis of HIV-infected individuals who have stable CD4 counts many years after seroconversion may provide an insight as to how the host's immune system can successfully control HIV infection. In this study we analysed the T-cell receptor (TCR) Vbeta repertoire in 13 HIV+ individuals, seven of whom were classed as long-term non-progressors (LTNP), using a technique which couples anchor PCR (AnPCR) amplification of beta-chain cDNA to differential probe hybridization with non-radioactively labelled Vbeta family specific oligonucleotide probes. There were no significant differences in the expressed TCR repertoires between the LTNP group and the other HIV-infected individuals. However, there was a statistically significant inverse correlation between CD4 count and the number of Vbeta family-specific perturbations in the recent seroconverters (SC) and those with progressive infection (PI), consistent with other shared features of clinical disease progression (Th1/Th2 switch and high frequency of viral isolation). We conclude that long-term clinical non-progression in HIV-1 infection is not associated with the loss or expansion of a particular Vbeta family; instead, low CD4 count in the PI and SC individuals was correlated with increased number of Vbeta family-specific perturbations relative to the LTNP group and that it is hence unlikely that HIV encodes a superantigen.