Cellular responses to invading pathogens utilize phagocytic and cytotoxic cells of the innate and adaptive immune responses.

The immune system is intimately connected with the hematologic system since white blood cells (leukocytes, including B- and T-lymphocytes) are key players in the lymphoid system.
Cellular participants in the immune and inflammatory responses include :
● phagocytic cells (dendritic cells, monocytes and macrophages, and granulocytes)
● antigen presenting cells (dendritic cells, macrophages, B lymphocytes, helper T cells, γδ T cells)
● antibody producing cells (plasma cells)
● cytotoxic cells (CTL, NK)
● regulatory cells (APCs, helper T cells, regulatory T cells)
● cells-in-waiting (memory B cells, monocytes)
● chemical releasing cells (basophils, eosinophils, neutrophils; mast cells – histamine, cytokines; hepatocytes – complement proteins)