Serum antibodies to antigens derived from a saline extract of Pasteurella haemolytica: correlation with resistance to experimental bovine pneumonic pasteurellosis.
The serum antibody response was determined to 6 antigen groups (AG's) derived from a saline extract (SE) of Pasteurella haemolytica, serotype 1. Using an enzyme-linked immunosorbent assay, sera were analyzed from 65 calves that had been previously vaccinated with saline, the unfractionated SE, a bacterin, or live P. haemolytica. The serum antibody responses to the 6 AG's were correlated with resistance to an experimental transthoracic challenge with the organism. The antibody responses to AG's 1, 5, and 6 appeared to be potentially important in resistance to challenge. In the 3 experiments conducted, a significantly higher (p less than 0.05) increase in antibody was seen to AG's 1, 5, and 6 in calves vaccinated with live organisms compared to those vaccinated with the bacterin. A significant correlation (p less than 0.05) was seen between high antibody to AG 1 and resistance to challenge in all 3 experiments. In 2 of the 3 experiments, a significant correlation (p less than 0.05) was seen among high antibody titers to AG's 5 and 6 and resistance, whereas in 1 experiment the correlation was significant (p less than 0.05) between antibody to AG 4 and resistance. A rise in antibody to AG's 2 and 3 was seen only in calves vaccinated with SE. Because AG's 1, 5, and 6 are higher in carbohydrate than the other AG's, this suggests that antibody to polysaccharide antigens may be important to resistance. Other potentially protective antigens of P. haemolytica are discussed.
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D000942:Antigens, Bacterial / Q000276:immunology / Q000302:isolation & purification; D001428:Bacterial Vaccines / Q000276:immunology / Q000494:pharmacology; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000517:prevention & control; D003603:Cytotoxins / Q000276:immunology; D007109:Immunity; D010326:Pasteurella Infections / Q000276:immunology* / Q000517:prevention & control / Q000662:veterinary*; D012766:Pasteurellosis, Pneumonic / Q000276:immunology* / Q000517:prevention & control
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D003603:Cytotoxins