Cross-sectional analysis of plasma IL-7 levels in sooty mangabeys. Plasma IL-7 levels are depicted for 13 uninfected (□) and 11 SIVsm-infected (○) sooty mangabeys, a species that does not progress to simian AIDS. Mean of each group is shown by horizontal line. The minimum detectable level of IL-7 was 0.10 pg/mL.