FIG. 1.

CD3-negative lymphocytes expressing IFN-γ in response to HIV peptides. Flow cytometric plots on gated lymphocytes from two subjects are shown. (A) Whole blood from HIV-infected subject 23 was stimulated with pools of HIV-1 consensus subtype B overlapping peptide pools in a 5-h ICS assay. Pol peptides were divided into two separate pools, and peptides for Rev, Tat, and Vpu and for Vif, Nef, and Vpr were combined. Gated lymphocytes were studied for expression of CD3 and intracellular IFN-γ. HIV-specific IFN-γ expression from non-CD3 lymphocytes in response to Pol and Env is detected. (B) Whole blood from HIV-infected subject 26 was similarly incubated with pools of overlapping 15-mer peptides from HIV-1 peptides for 5 h. Gated lymphocytes were studied for CD3 and intracellular IFN-γ expression as above. A large proportion of CD3-negative cells produced IFN-γ in response to the combined Rev, Tat, and Vpu peptide.