Phenotypic characterization of HIV-infected subpopulation. (A) CD4⁺ T cells were infected as described. The cells were immunostained for p24 and CD95 (i-iii), CD25 (iv-vi), TUNEL and CD95 (vii-ix), or Bcl-2 (x-xii). Expression of each marker in uninfected, bystander, and HIV-infected populations is shown from one representative donor. (B) Mean fold increase of each marker in panel A over HIV-uninfected cultures from 3 donors. ^*P < .05.