HIV-specific cytotoxicity increases after overnight culture in an IL-2–dependent manner from PBMCs of HIV-infected donors 228 (A), 237 (B), and 307 (C). Cytotoxicity is measured as in Fig 1against targets expressing lacZ control (vSC8), gp160 (vPE16), RT (vCF21), and gag (vDK1). The percent of CD8 T cells that express CD3ζ increases concomitantly.