Cross-protection factor(s) of Pasteurella multocida: passive immunization of turkeys against fowl cholera caused by different serotypes.

An antiserum cross-protective against different serotypes of Pasteurella multocida was made in turkeys by inoculating them with killed serotype 3 organisms grown in vivo and then exposing them to live serotype 3 organisms. In passive-immunization studies, the antiserum protected young turkeys against the homologous and heterologous serotypes 1, 4, 5, 9, and 12. In addition, the antiserum protected against P. multocida of a heterologous capsule serogroup, serogroup F. A globulin and two IgG fractions purified from the antiserum protected against heterologous challenge with serotype 1. Turkey-grown P. multocida were chemically lysed and separated into soluble and insoluble components to make immunoadsorbents. Antibodies from the cross-protective antiserum isolated by the immunoadsorbents passively protected young turkeys against heterologous serotype I challenge.