The branch of the immune system in which the reaction to foreign material is performed by specific defence cells ( killer cells , macrophage and other white blood cells ) rather than antibodies.

Humoral Immunity

Any immune reaction that can be transferred with immune serum is termed humoral immunity (as opposed to cell-mediated immunity). In general, this term refers to resistance that results from the presence of specific antibodies ( immunoglobulins ). These antibodies circulate through the blood and lymph system. When blood is spun in centrifuge, the red blood cells fall to the bottom of the tube, leaving behind a straw-colored liquid called the serum . Antibodies are located in the blood serum and thus can be transferred with an immune serum.