ABSTRACT
When macrophages take up microorganisms by phagocytosis, they secrete interleukin (IL)-12. This cytokine is necessary for the induction of IFN-g synthesis by T cells and natural killer (NK) cells. IL-12 furthermore favors the maturation of TH1 cells, which activate macrophages, and suppresses the maturation of TH2 cells, which secrete a cytokine, IL-10, involved in the deactivation of macrophages.
