title: Characterization of two different types of direct plaque-forming cells.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000941:Antigens; D004912:Erythrocytes / Q000276:immunology; D006386:Hemagglutination Tests; D006462:Hemolytic Plaque Technique; D007106:Immune Sera; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D008297:Male; D051379:Mice; D012756:Sheep; D013154:Spleen / Q000166:cytology* / Q000276:immunology
chemical_list: D000941:Antigens; D007106:Immune Sera