PASSIVE CROSS-PROTECTION PROVIDED BY ANTISERA DIRECTED AGAINST IN-VIVO-EXPRESSED ANTIGENS OF PASTEURELLA-MULTOCIDA

Chicken antisera produced against the detergent-insoluble fraction of in vivo-grown P-1059 (serotype 3) Pasteurella multocida passively prot ected against heterologous X-73 (serotype 1) challenge. Likewise, anti sera from chickens that survived infection by live P-1059 provided pas sive heterologous protection. The two antisera, which contained cross- protection antibodies, were adsorbed with the detergent-insoluble frac tion of in vitro-grown P-1059 and still passively cross-protected agai nst heterologous serotype challenge. The proteins of in vivo-grown P-1 059 that had molecular weights of 204,000, 192,000, 179,000, and 153,0 00, which were recognized by the adsorbed antisera on immunoblots, may be responsible for cross-protection.