Ex vivo γδ T cells from HIV-1–infected patients express IFN-γ: response to microbial antigen stimulation. PBMCs from HIV-1–infected Pts (A: 1 representative Pt; n = 30 Vδ1 and n = 4 Vδ2 in C) or Hds (B: 1 representative Hd; n = 10 in D) were surface stained with the APC–anti-CD3 (Ai-Aiv, Bi-Biv) the FITC-conjugated A13 or BB3 mAbs to identify Vδ1 (Ai-ii, Bi-ii) or Vδ2 (Aiii-iv, Biii-iv) T cells and cytoplasmically stained with PE-anti–IFN-γ (performed immediately after isolation, Ai-Aiv and Bi-Biv, and ex vivo in C and D) or after 7 days of culture with IPP, PPD, CMV, PC, or Ca and rIL-2 was added on day 4 (C,D). (C,D) None indicates PBMCs cultured in the absence of antigens. Samples were analyzed by FACSCanto flow cytometer (Becton Dickinson). Results are expressed as mean far red (APC) fluorescence intensity (x-axis, arbitrary units, au) versus mean green (FITC) fluorescence intensity (y-axis, au; Ai, Aiii and Bi, Biii) or as mean green (FITC) fluorescence intensity (x-axis, au) versus mean red (PE) fluorescence intensity (y-axis, au; Aii, Aiv and Bii, Biv). In the top right quadrant of contour plots in Aii, Aiv, Bii, and Biv, the percentage of IFN-γ⁺ cells among Vδ1 or Vδ2 T cells, gated as shown in Ai, Bi or Aiii, Biii, respectively, is indicated. (C,D) Percentage of IFN-γ⁺ Vδ1 (■) or Vδ2 (□) on PBMC from Pts (C) or Hds (D) before and after culture with the indicated antigens; mean ± SD from 30 Pts (n = 30 Vδ1 and n = 4 Vδ2) and 10 Hds: *P < .01 versus ex vivo or versus none. (C) **P < .01 versus Hds.