title: The preparation of antigens from yolk sacs infected with rickettsiae.
authors.forename: N H
authors.initials: NH
authors.lastname: TOPPING
authors.forename: C C
authors.initials: CC
authors.lastname: SHEPARD
mesh_terms: D000941:Antigens; D006801:Humans; D007109:Immunity; D012281:Rickettsia; D014438:Typhus, Epidemic Louse-Borne; D015017:Yolk Sac
chemical_list: D000941:Antigens
keywords: TYPHUS/immunity