Immunophenotyping of peripheral blood CD4⁺ T lymphocytes from CMV-seropositive healthy adults. (A) Flow cytometry histograms are all gated on CD3⁺CD4⁺ lymphocytes and are representative of results obtained for at least 4 different individuals. (B) Flow cytometry histograms, gated on lymphocytes, showing cell sorting of CCR5⁺ and CCR5^- subpopulations of CD4⁺ cells from buffy coats. (C) Proliferation of PBMCs and purified CCR5⁺ and CCR5^- CD4⁺ T lymphocytes from CMV-seropositive healthy adults, in response to CMV lysate. Error bars show SD for duplicates, and cpm in unstimulated cultures ranged from 600 to 1200. Results are representative of 3 independent experiments.