Vaccine samples.

HVTN 502 participants (MRKAd5, ClinicalTrials.gov identifier {"type":"clinical-trial","attrs":{"text":"NCT00095576","term_id":"NCT00095576"}}NCT00095576) were randomized to receive the Ad5 vaccine with HIV-1 gene inserts (gag, pol, nef) or placebo (22). HVTN 505 participants (DNA/rAd5, ClinicalTrials.gov identifier {"type":"clinical-trial","attrs":{"text":"NCT00865566","term_id":"NCT00865566"}}NCT00865566) were randomized to receive the DNA/rAd5 vaccine with HIV-1 gene inserts (gag, pol, env a/b/c, nef [DNA only]) or placebo (18). Informed consent was obtained from all participants, and all relevant guidelines of the authors’ institutions were followed. A total of 46 vaccine recipients (37 from MRKAd5 and 9 from DNA/Ad5) who were previously found to have positive responses to vaccine-encoded epitopes (5) were screened for cross-reactive CD8 T-cell responses for this study. Of the MRKAd5 recipients, 13 were individuals who eventually became HIV-1 infected. Five placebo recipients from MRKAd5 and two from DNA/Ad5 were tested for vaccine responses, and no positive responses were detected in these recipients.