title: Interactions of leukocytes in phylogenetic perspective.
mesh_terms: D000818:Animals; D002450:Cell Communication; D006649:Histocompatibility Antigens / Q000502:physiology; D008211:Lymphocyte Cooperation; D010802:Phylogeny; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006649:Histocompatibility Antigens