Macrophages are covered with chemical receptors and phagocytose foreign particles, but are specific about what immune responses to be involved in.
Dendritic cells phagocytose invaders; then they present the antigen on their surface to stimulate the acquired immune system (lymphocytes) as backup.
TH17 cells do a variety of tasks including recruiting neutrophils, creating defensins, and mediating inflammation in the intestinal epithelium and skin.
TH1 cells are created to make cytokines, like interferon gamma, that activate macrophages and cytotoxic T lymphocytes (CTLs).
Once activated by T lymphocytes or Natural Killer cells,[3] interferon gamma upregulates expression of macrophages and both types of Major Histocompatibility Complex (MHC) antigens.