Activation of infected macaque PBMCs in vitro. Non-stimulated macaque PBMCs were infected with PBj-wt or PBj-Nef202/203GG virus. (A and B) FACS analysis of cell surface expression of T cell activation marker CD25 on day 10 p.i. (A) Histograms of one representative animal. (B) Scattergram of CD25 surface expression on T cells of 4 different animals, horizontal bars represent means (**, P < 0.04; ***, P < 0.001). (C) IL-2 concentration and (D) IL-6 concentration was measured in tissue culture supernatants of infected PBMCs of 3 different animals by ELISA. Error bars, SD.