Activation in infected and uninfected CD4⁺ T cells in HIV-1–infected tissues. Tissue blocks from 3 different donors (54 blocks for each data point) were infected with X4_LAI.04. CD4⁺ T cells from infected and matched uninfected tissues were stained for activation markers (HLA-DR and CD25) and for p24gag and analyzed by flow cytometry. The graphs represent the averages (± SEM) of CD25⁺/HLA-DR⁺ CD4⁺ T cells at days 5 and 12 after infection. CD25⁺/HLA-DR⁺ CD4⁺ T cells in uninfected control tissue. CD25⁺/HLA-DR⁺ CD4⁺ T cells were divided in X4_LAI.04 infected tissue in productively infected cells (p24gag⁺) and bystander cells (p24gag⁻). * Represents significant differences for a nonparametric paired T test.