Q. What are the antigen-presenting cells of the immune system?
The antigen-presenting cells of the immune system also known as APC cells are cells that do digestion and phagocytosis of foreign (to the body) microorganisms and later expose antigens derived from these microorganisms in the outer side of their plasma membrane. These processed antigens are then recognized by lymphocytes that activate the immune response. Several kinds of cells, like the macrophages, can act as antigen-presenting cells.