Limited Immunogenicity of HIV CD8 super(+) T-Cell Epitopes in Acute Clade C Virus Infection

• Published in: The Journal of infectious diseases 2011-09, Vol.204 (5), p.768-776
• Main Authors: Radebe, Mopo, Nair, Kriebashnie, Chonco, Fundisiwe, Bishop, Karen, Wright, Jaclyn K, van der Stok, Mary, Bassett, Ingrid V, Mncube, Zenele, Altfeld, Marcus, Walker, Bruce D, Ndung'u, Thumbi
• Format: Article
• Language: English
• Subjects: Human immunodeficiency virus 1
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1093/infdis/jir394

Background. Human immunodeficiency virus type 1 (HIV-1)-specific CD8 super(+) responses contribute to the decline in acute peak viremia following infection. However, data on the relative immunogenicity of CD8 super(+) T-cell epitopes during and after acute viremia are lacking. Methods. We characterized CD8 super(+) T-cell responses in 20 acutely infected, antiretroviral-naive individuals with HIV-1 subtype C infection using the interferon- gamma enzyme-linked immunosorbent spot assay. Eleven of these had not fully seroconverted at the time of analysis. Viruses from plasma were sequenced within defined cytotoxic T-lymphocyte (CTL) cell epitopes for selected subjects. Results. At approximately 28 days after estimated initial infection, CD8 super(+) T-cell responses were directed against an average of 3 of the 410 peptides tested (range, 0-6); 2 individuals had no detectable responses at this time. At 18 weeks, the average number of peptides targeted had increased to 5 (range 0-11). Of the 56 optimal Gag CTL epitopes sequenced, 31 were wild-type in the infecting viruses, but only 11 of 31 elicited measurable CD8 super(+) T-cell responses. Conclusions. These data demonstrate that the majority of CD8 super(+) responses are not elicited during acute HIV infection despite the presence of the cognate epitope in the infecting strain. There is a need to define factors that influence lack of induction of effective immune responses and the parameters that dictate immunodominance in acute infection.