Fig. 2

Increased frequency of CD57-expressing CD4⁺ and CD8⁺ T cells in HIV-infected subjects. PBMC samples were analyzed by flow cytometry by first gating on the total mononuclear cells and then on the CD3⁺ T cells. The frequency of CD57⁺ cells among the (a) total CD4⁺ T cells, (b) CD28-expressing CD4⁺ T cells or (c) CD28-negative CD4⁺ T cells was determined. Next, the frequency of CD57⁺ cells among the (d) total CD8⁺ T cells, (e) CD28-expressing CD8⁺ T cells or (f) CD28-negative CD8⁺ T cells was determined using Mann–Whitney U-tests. The error bars represent ± 1 SD