The immune system "belongs in the body".
D000818:Animals; D001921:Brain / Q000276:immunology; D005260:Female; D006801:Humans; D007109:Immunity; D066298:In Vitro Techniques; D008214:Lymphocytes / Q000502:physiology; D008297:Male; D009420:Nervous System / Q000276:immunology*; D051381:Rats; D013315:Stress, Psychological / Q000276:immunology