title: Speculation on the phylogeny of cellular recognition.
mesh_terms: D000818:Animals; D000845:Annelida; D000917:Antibody Formation; D001770:Blood Bactericidal Activity; D003063:Cnidaria; D005399:Fishes; D005802:Genes, MHC Class II; D006680:HLA Antigens / Q000235:genetics; D007111:Immunity, Cellular; D007448:Invertebrates / Q000276:immunology*; D010802:Phylogeny; D011161:Porifera
chemical_list: D006680:HLA Antigens