IL-7 upregulates the IL-2 and IFN-γ secretion of activated human T lymphocytes. T cells were left unstimulated or stimulated with PHA or PHA plus anti-CD28 (aCD28) in the presence or absence of IL-7. Cell free supernatants were harvested after 12 and 24 hours and analyzed for secreted (A) IL-2 protein and (B) IFN-γ protein with ELISAs. The mean values for the IL-2 and IFN-γ secretion found in four independent experiments are shown.