Fig. 1

PBMC gating strategy. PBMCs were isolated as described. An initial acquisition gate on the FSC versus the SSC profile that excluded most of the non-lymphocytes was introduced to minimize background fluorescence. T cells were identified using an anti-CD3 Ab. CD4⁺CD3⁺ cells and CD8⁺CD3⁺ cells were then gated and screened for the expression of the chemokine receptors CXCR4 and CCR5