RANTES enhances HIV-1–specific CTL activity. (A) Transformed autologous B cells infected with recombinant vaccinia virus expressing Gag HIV-1 antigens were used as targets. Lysis by HIV-1–specific CTLs was determined in the presence of 25 nM RANTES (closed squares), 1 μg/ml anti-RANTES (open circles), or without additions (closed circles). No lysis was obtained in the presence or absence of 25 nM RANTES (open squares and closed triangles, respectively) when transformed autologous B cells infected with wild-type recombinant vaccinia virus were used as targets. Similar effects were obtained in eight experiments with CTLs from different HIV-1–infected donors. (B) Transformed autologous B cells preincubated with the synthetic peptide 476–484 corresponding to the Pol epitope of HIV-1LAI were used as targets. Lysis by HIV-1–specific CTLs was determined in the presence of 25 nM RANTES (closed squares), 25 nM RANTES(9-68) (open squares), 1 μg/ml anti-RANTES (open circles), or without additions (closed circles). Data from one experiment. (C) Human plasmocytoid cells Hmy cotransformed with the HLA-A2 and the HIV-1LAI nef genes were used as targets. Lysis by HIV-1–specific CTLs was determined in the presence of 25 nM RANTES (closed squares), 25 nM RANTES(9-68) (open squares), 1 μg/ml anti-RANTES (open circles), or without additions (closed circles). The data are representative for two experiments. (D) RANTES does not affect the lytic activity of NK cells. Lysis of K562 target cells by NK cells obtained from venous blood of healthy donors was determined in the presence of 25 nM RANTES (closed squares), 1 μg/ml anti-RANTES (open circles), or without additions (open squares). The data are representative for four experiments. (E) Effects of 25 nM RANTES, 1 μg/ml anti-RANTES and 25 nM RANTES(9−68) on the activity of HIV-1–specific CTLs from eight different donors. Transformed autologous B cells infected with recombinant vaccinia virus expressing Gag (squares), Pol (circles), or Env (triangles) were used as targets. Data are shown for an E/T ratio of 40:1. The straight lines connect the lytic activity values obtained in the absence (−) or presence (+) of the added reagent as indicated.