Background: Most of HIV vaccine trials are conducted with clade B subtype while the majority of infected individuals living in Africa are contaminated with non-B clade HIV. An efficient vaccine against HIV must induce good cellular immune responses. In order to evaluate the feasibility of a HIV vaccine trial in Ivory Coast, we analyzed whether CD8⁺ T-cells from Ivorian patients (pts) infected with HIV clade A/G were able to recognize clade B epitopes included in vaccine candidates currently tested in France.

Methods: Fresh whole blood was collected from 9 Ivorian infected with HIV-1 CRF02-AG subtype. CD8⁺ T-lymphocyte responses against 110 HIV-1 clade B peptides that are well defined CD8⁺ T-epitopes (in Nef, Gag, RT and Env regions) and pooled by 10, were measured by Elispot IFNg. Sequencing of rt, gag and nef HIV gene of theses pts were done in order to identify variations in the epitope sequences. Samples from French cohort infected with HIV-1 clade B were tested similarly.

Results: All Ivorian pts had CD8⁺ T responses against at least 1 pool. Five (5) of the nine Ivorian pts recognised at least 5 out of the 11 pools. Peptides that induced CD8⁺ T responses were also identified in some pts. There was no difference in the number of recognized pool between Ivorian and French cohort (p = 0.62, Fischer test). Sequence analysis revealed very few variations in nef and gag immunodominant regions between HIV clade AG and clade B.

Conclusions: Data of this study show that individuals infected with subtype AG HIV-1 can generate cross-reactive CD8⁺ T against HIV-1 subtype B. Furthermore there is no major variation in immunodominant regions corresponding to HIV clade B vaccine candidates in particular lipopeptide vaccines currently tested in France (ANRS Vac04, Vac10, Vac12). These promising results allow us to consider a vaccine trial in Ivory Coast using HIV clade B lipopeptides.