Low CCR5 expression protects HIV-specific CD4+ T cells of elite controllers from viral entry.

HIV elite controllers maintain a population of CD4 + T cells endowed with high avidity for Gag antigens and potent effector functions. How these HIV-specific cells avoid infection and depletion upon encounter with the virus remains incompletely understood. Ex vivo characterization of single Gag-specific CD4 + T cells reveals an advanced Th1 differentiation pattern in controllers, except for the CCR5 marker, which is downregulated compared to specific cells of treated patients. Accordingly, controller specific CD4 + T cells show decreased susceptibility to CCR5-dependent HIV entry. Two controllers carried biallelic mutations impairing CCR5 surface expression, indicating that in rare cases CCR5 downregulation can have a direct genetic cause. Increased expression of ß-chemokine ligands upon high-avidity antigen/TCR interactions contributes to autocrine CCR5 downregulation in controllers without CCR5 mutations. These findings suggest that genetic and functional regulation of the primary HIV coreceptor CCR5 play a key role in promoting natural HIV control.

Public T cell receptors confer high-avidity CD4 responses to HIV controllers.

The rare patients who are able to spontaneously control HIV replication in the absence of therapy show signs of a particularly efficient cellular immune response. To identify the molecular determinants that underlie this response, we characterized the T cell receptor (TCR) repertoire directed at Gag293, the most immunoprevalent CD4 epitope in the HIV-1 capsid. HIV controllers from the ANRS CODEX cohort showed a highly skewed TCR repertoire that was characterized by a predominance of TRAV24 and TRBV2 variable genes, shared CDR3 motifs, and a high frequency of public clonotypes. The most prevalent public clonotypes generated TCRs with affinities at the higher end of values reported for naturally occurring TCRs. The high-affinity Gag293-specific TCRs were cross-restricted by up to 5 distinct HLA-DR alleles, accounting for the expression of these TCRs in HIV controllers of diverse genetic backgrounds. Transfer of these TCRs to healthy donor CD4+ T cells conferred high antigen sensitivity and polyfunctionality, thus recapitulating key features of the controller CD4 response. Transfer of a high-affinity Gag293-specific TCR also redirected CD8+ T cells to target HIV-1 capsid via nonconventional MHC II restriction. Together, these findings indicate that TCR clonotypes with superior functions are associated with HIV control. Amplification or transfer of such clonotypes may contribute to immunotherapeutic approaches aiming at a functional HIV cure.

Early control of HIV-1 infection in long-term nonprogressors followed since diagnosis in the ANRS SEROCO/HEMOCO cohort.

BACKGROUND: To clarify early correlates and natural history of HIV long-term nonprogressors (LTNPs) since HIV diagnosis. METHODS: Patients enrolled in the French ANRS SEROCO/HEMOCO cohort with CD4 count >500 cells/mm3 at HIV diagnosis. LTNP status was defined as being asymptomatic, antiretroviral free, and with CD4 cell count >500 cells/mm3 for >8 years after HIV diagnosis. In LTNPs, we modeled the biological markers' progression through a joint model. Factors associated with loss of LTNP status were identified through a Cox model. RESULTS: Sixty (9%) of 664 patients were identified as LTNPs during follow-up. At enrollment, HIV RNA was 1.85 log copies/10(6) PBMCs and high HIV DNA increase were associated with an increased risk of losing LTNP status [adjusted hazard ratio: 2.8 (1.2-6.8) and 2.2 (1.0-4.8), respectively]. CONCLUSIONS: LTNP status is established in the first years of HIV infection, low HIV DNA level at enrollment and slow increase of HIV DNA being associated with maintained LTNP status.