Cancer may develop when the immune system breaks down or is not functioning adequately. Biological therapies are designed to repair, stimulate, or enhance the immune system's responses. Types of lymphocytes include B cells, T cells, and Natural Killer cells. Each type of B cell makes one specific antibody, which recognizes one specific antigen. T cells also regulate the immune response by signaling other immune system defenders.
T cells work primarily by producing proteins called lymphokines.
They attack without first having to recognize a specific antigen. Monocytes are white blood cells that can swallow and digest microscopic organisms and particles in a process known as phagocytosis. Antibodies respond to antigens by latching on to, or binding with, the antigens. Specific antibodies match specific antigens, fitting together much the way a key fits a lock. Cytokines are substances produced by some immune system cells to communicate with other cells.