In the presence of antigens these lymphocytes produce cells with antibody bound to their surface. They can attack whole cells and are responsible for such reactions as graft rejection, allergic responses, and delayed hypersensitivity reactions. In humans they are probably formed by lymphatic tissue in the gut. B-lymphocytes produce cells that release free antibody into the blood, neutralizing bacterial toxins and coating bacteria to facilitate their ingestion by the phagocytic cells. See also immunosuppression .
Immunization is the production of immunity by artificial means.
The Macmillan Encyclopedia 2001 5. All rights reserved.