The Human Body

Cell-Mediated Immune Response

As with the humoral immune response, the cell-mediated immune response involves a complex series of events after antigens enter the body. Helper T cells are required, so some of the antigen must be taken up by macrophages and presented to helper T cells. The helper T cells bind the presented antigen and thereby become activated to divide and secrete interleukins. The interleukins in turn activate any killer T cells that have already bound antigen attached to class I MHC molecules on infected cells. The activated killer T cells can then kill any cells displaying antigen attached to class I MHC molecules, effectively eliminating any cells infected with the antigen.