title: How the immune system works.
mesh_terms: D000937:Antigen-Antibody Reactions; D000941:Antigens / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007154:Immune System Diseases / Q000276:immunology; D007109:Immunity; D008264:Macrophages / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000941:Antigens