FIG. 3.

SIV infection leads to a severe depletion of CD3⁺CD4⁺ and CD3⁺CD4⁺CD8⁺ IEL and an increase in the proportion of CD3⁺CD8⁺ IEL, without a major change in the proportions of CD3⁺ IEL. Isolated IEL were stained for cell surface expression of CD3, CD4, and CD8 antigens and were analyzed by flow cytometry. Negative-control samples were stained with matched isotype control antibodies. CD3⁺ (▪), CD3⁺CD4⁺ (⧫), CD3⁺CD8⁺ (•), CD3⁺CD4⁺CD8⁺ (▴), and CD3⁺CD4⁻CD8⁻ (✚) IEL are indicated as percentages of gated lymphocytes.