Section A - OVERVIEW OF THE IMMUNE SYSTEM. The need. External defenses. Immune defense. Antigens. Section B - CELLS OF THE INNATE IMMUNE SYSTEM. Phagocytes. Natural killer cells. Mast cells and basophils. Dendritic cells. Other cells of the innate immune system. Section C - MOLECULES OF THE INNATE IMMUNE SYSTEM. Innate molecular defense against microbes. Complement. Acute phase proteins. Interferons. Other molecules. Section D - ADAPTIVE IMMUNE SYSTEM: LYMPHOCYTES, LYMPHOID ORGANS AND TISSUES. Lymphocytes. Lymphoid organs and tissues. Mucosa-associated lymphoid tissues. Lymphocyte traffic and recirculation. Section E - DEVELOPMENT OF THE IMMUNE SYSTEM. Haemopoiesis - development of blood cells. T cells are produced in the thymus. B cells are produced in the bone marrow. Immunity in the newborn. Section F - ANTIBODIES. Basic structure. Antibody classes. Generation of diversity. Allotypes and Idiotypes. Functions. Monoclonal antibodies. Section G - CYTOKINES. Molecules with multiple functions. Cytokine families. Cytokines in the clinic. Section H - ANTIGEN RECOGNITION. Non-self recognition by the innate immune system. B cell recognition of antigen, the B cell receptor complex and co-receptors. T cell recognition of antigen, the T cell receptor complex. The Major histocompatibility complexes (MHC), antigen processing and presentation. Section I - THE ACUTE INFLAMMATORY RESPONSE. The acute inflammatory response. Section J - THE ANTIBODY RESPONSE. The cellular basis of the antibody response. Section K - THE T CELL RESPONSE - CELL MEDIATED IMMUNITY. Cell mediated immunity. T cytotoxic cells. T helper cells. Section L - LYMPHOCYTE ACTIVATION. Receptors, co-receptors and signaling. T cell activation. B cell activation. Section M - SELF AND NON-SELF DISCRIMINATION. Cell recognition of self and non-self. Central tolerance. Peripheral tolerance. Acquired tolerance. Section N - REGULATION OF THE IMMUNE RESPONSE. Components involved in immune regulation. The role of antigen. Gene, T helper cells and cytokines. The role of antibody. Other control mechanisms. Section O - IMMUNITY TO INFECTION. The microbial cosmos. Immunity to different organisms. Pathogen defence strategies. Section P - TUMOR IMMUNOLOGY. Origin and host defence against tumors. Tumor antigens. Immune responses to tumors. Immunodiagnosis. Cytokine and cellular immunotherapy of tumors. Immunotherapy of tumors with antibodies. Tumor vaccines. Section Q - TRANSPLANTATION. The transplantation problem. Transplantation antigens. Rejection mechanisms. Prevention of graft rejection. Section R - VACCINATION. Principles of vaccination. Immunization. Antigen preparations. Vaccines to pathogens and tumors. Section S - IMMUNODEFICIENCY - WHEN THE IMMUNE SYSTEM FAILS. Deficiencies in the immune system. Primary/congenital (inherited) immunodeficiency. Secondary (aquired) imm