FIG. 1.

DNA PCR of the nef gene. (A) SIVmac239Δnef or SIVmac251 nef sequences were detected in PBMC samples obtained at 100 days postchallenge by using two sets of primer pairs (1 and 2). (B) Products amplified by primer set 1 showing both the Δnef fragment and the wild-type (wt) nef fragment. (C) Products amplified by primer set 2 showing only wild-type nef. Individual macaques are identified by the animal number and a letter representing the challenge group: A, 5-week challenge; B, 10-week challenge; D, 25-week challenge. 1480-A and 1492-B represent nonimmunized control animals in the 5- and 10-week challenge groups, respectively.