The humoral response involved mostly B cells that recognize antigens or pathogens that are circulating in the blood. The response that occurs happens through a chain of events. First, the antigen binds to the B cell. Then, helper cells activate the B cell. The B cell then produces plasma cells, which bear antibodies. The antibodies are released and circulate the body to bind to antigens. B cells also produce memory cells, which provide future immunity.
The cell mediated response involves T cells and a chain of events occurs to trigger an immune response. Self cells bind to T cells, which then are activated by interleukins. If endogenous antigens are present, T cells produce cytotoxic T cells. If exogenous antigens are displayed, T cells produce helper T cells.