title: Studies on protective antigen of Bordetella pertussis: isolation of protective antigen by sucrose density gradient centrifugation and some properties of the antigen.
mesh_terms: D000941:Antigens; D001886:Bordetella pertussis / Q000276:immunology*; D066298:In Vitro Techniques; D013501:Surface-Active Agents; D014461:Ultracentrifugation
chemical_list: D000941:Antigens; D013501:Surface-Active Agents