No Major Differences in the Functional Profile of HIV Gag and Nef-Specific CD8+ Reponses between Long-Term Nonprogressors and Typical Progressors

Abstract The mechanism explaining the failure of HIV-specific CD8+ T cell responses to successfully control HIV replication remains elusive. A total of 83 drug-naive HIV-infected individuals, 27 of whom were long-term nonprogressors (LTNP), was examined. The ability of CD8+ T lymphocytes to produce three different cytokines (MIP-1β, TNF-α, IL-2) in response to HIV Gag and Nef peptides and to polyclonal stimuli and the ability of HIV-specific CD8+ T cells to expand in vitro were evaluated by multiparameter flow cytometry. In response to polyclonal stimulation, LTNP presented significantly higher levels of several CD8+ T cell subsets than progressors. While most patients presented detectable Gag and Nef-specific CD8+ responses, no significant differences in any of the CD8+ functional T cell subsets were recognized when comparing LTNP and progressors. HIV responses were dominated by cells producing only MIP-1β or TNF-α, being similar in LTNP and progressors. However, expansion of HIV-specific CD8+ T cells wa...