CD3ζ is downmodulated to a greater extent in CD8 T cells than CD4 T cells. Gated lymphocytes were analyzed for triple staining with antibodies to CD3ζ with CD3 and CD20 or CD4 and CD8. (A) Profile of a healthy donor (I), asymptomatic, slow-progressor subject no. 6156 (II), and AIDS patient no. 355 (III). (B) Representative results from healthy donors, asymptomatic HIV-infected donors and AIDS patients show progressive downmodulation of ζ in CD8 more than CD4 T cells. The percent of CD20 B cells (□), CD3 T cells (▧), CD4 T cells (⊡) and CD8 T cells (▪) that costain with ζ is shown.