title: Vaccination of turkeys with cell-free culture filtrate of Pasteurella multocida: effects of dilution, iron chelation, and heterologous challenge.
abstract: Two experiments were done to further define cell-free culture filtrate (CCF) from Pasteurella multocida and its endotoxin content in protecting turkeys against challenge. In the first experiment, the greater-than-30,000-molecular-weight fraction of P. multocida strain R44/6 (serotype 3/4/9/12) CCF was used in 10-fold dilutions given by air-sac inoculation or aerosol to vaccinate turkeys, which were subsequently challenged with either homologous (P-1059, serotype 3) or heterologous (X-73, serotype 1) strains. Endotoxin content of the CCF fraction was high. Compared with positive controls given either live Clemson University vaccine or a commercial bacterin, homologous protection was provided by undiluted CCF and 1:10 dilutions of CCF, but there was no heterologous protection. In the second experiment, CCF of strain R44/6 in regular and iron-limiting media and CCF of strain FC127B (serotype 1/4) were used alone or in combination to vaccinate turkeys, which were challenged as in the first experiment. Homologous but not heterologous protection occurred, even though growth of strain R44/6 in iron-limiting media reduced endotoxin content of CCF by approximately 93%. These results indicate that endotoxin levels of less than 10% but greater than 1% of those in CCF from regular media are sufficient to induce protection in turkeys against homologous challenge but that CCF from either regular or iron-limiting medium does not provide protection against heterologous challenge.
authors: Department of Food Animal and Equine Medicine, College of Veterinary Medicine, North Carolina State University, Raleigh 27606.
authors: M D
authors: MD
authors: Ficken
authors: H J
authors: HJ
authors: Barnes
authors: A P
authors: AP
authors: Avakian
authors: D K
authors: DK
authors: Carver
mesh_terms: D000336:Aerosols; D000818:Animals; D001428:Bacterial Vaccines; D004731:Endotoxins / Q000032:analysis / Q000276:immunology; D007201:Indicator Dilution Techniques / Q000662:veterinary; D007267:Injections / Q000662:veterinary; D007502:Iron Chelating Agents; D008297:Male; D010326:Pasteurella Infections / Q000517:prevention & control / Q000662:veterinary*; D016979:Pasteurella multocida / Q000737:chemistry / Q000276:immunology*; D011201:Poultry Diseases / Q000517:prevention & control*; D014422:Turkeys / Q000276:immunology*; D014462:Ultrafiltration
chemical_list: D000336:Aerosols; D001428:Bacterial Vaccines; D004731:Endotoxins; D007502:Iron Chelating Agents