The mitogen-induced generation of interferon-gamma producing cells in cultures of rhesus monkey peripheral blood mononuclear cells is age-dependent.

An enzyme-linked immunoabsorbent spot (ELISPOT) assay has been developed for measuring the frequency of interferon-gamma (IFN-gamma) producing cells in rhesus monkeys. Aged monkeys revealed, upon mitogenic stimulation, a significantly higher percentage of IFN-gamma secreting peripheral blood mononuclear cells (PBMC) compared to young animals. No correlation was found between the frequency of IFN-gamma producing PBMC and the mitogen-driven proliferation, indicating that in rhesus monkeys no direct correlation exists between these two activation parameters.