Baseline Ad5 serostatus does not predict Ad5 HIV vaccine-induced expansion of adenovirus-specific CD4+ T cells

Hutnick NA, Carnathan DG, Dubey SA, Cox KS, Kierstead L, Ratcliffe SJ, Robertson MN, Casimiro DR, Ertl HC, Betts MR. (2009) Nat Med. 15:876-8

The mechanisms underlying possible increased HIV-1 acquisition in adenovirus 5 (Ad5)-seropositive subjects vaccinated with Ad5-HIV-1 vectors in the Merck STEP trial remain unclear. We find that Ad5 serostatus does not predict Ad5-specific CD4(+) T cell frequency, and we did not observe durable significant differences in Ad5-specific CD4(+) T cells between Ad5-seropositive and Ad5-seronegative subjects after vaccination. These findings indicate no causative role for Ad5-specific CD4(+) T cells in increasing HIV-1 susceptibility in the STEP trial.