CD4 and HIV-1 infection: As with the data regarding HIV-1 infection and CD4 T cell depletion we first compared activation of T cells by their expression of CD25, CD38, and HLA-DR in donor-matched tissues infected with a T/F HIV-1 construct, NL-1051.TD12.ecto and a control C/R HIV-1 variant, NL-SF162.ecto.