T-cell regulation of macrophage function.

Macrophage function has long been known to be controlled by activated T cells. As the cytokines that control macrophage activation are defined, it is becoming apparent that macrophage 'activation' is more subtle than previously appreciated. Moreover, recent work has shown the dependence of T-cell development on macrophages, from the costimulation of T cells by macrophage surface molecules such as the B7 family, to the modulation by monokines of T-cell phenotype and growth, including IL-1, IL-10, IL-12 and IL-15. Combinations of cytokines and costimulators have revealed some of the processes by which an apparently dichotomous T-cell response can regulate the subtle diversity of the immune response.