Protection against colibacillosis in neonatal piglets by immunization of dams with procholeragenoid.
Protection against colibacillosis in neonatal piglets was obtained by immunization of pregnant dams with procholeragenoid. Procholeragenoid is a stable high-molecular-weight aggregate of cholera toxin formed during the heating of cholera toxin. Procholeragenoid retained approximately 1% of the toxicity of native toxin as determined in the rabbit ileal loop and Y-1 adrenal cell assays and 5% of the activity in the rabbit skin assay. Immunization of pregnant dams with 50 micrograms of procholeragenoid 5 and 2 weeks before the expected delivery date elicited high titers of antitoxic immunoglobulin G and toxin-neutralizing antibody in both the colostrum and serum. In three independent field trials, immunization with procholeragenoid resulted in a substantial decrease in diarrhea (73% in controls versus 11% in immunized) and death (4.7% in controls versus 0.77% in immunized) in neonatal piglets. The protection rate in the immunized population was approximately 85% for both diarrhea and death. In the following gestation period, reimmunization of dams with a single dose of procholeragenoid (50 micrograms) 2 weeks before delivery elicited titers of antitoxic immunoglobulin G and toxin-neutralizing antibody comparable to those obtained during the primary immunization. The death rate in neonatal piglets (0.86%) was comparable to that seen after immunization during the first gestation period (0.77%). These results indicate that substantial protection of neonatal piglets against colibacillosis can be obtained by immunization of dams with procholeragenoid. Protection was found to be based solely on antitoxic immunity.
D000818:Animals; D000831:Animals, Newborn; D000992:Antitoxins / Q000096:biosynthesis; D002772:Cholera Toxin / Q000276:immunology; D003126:Colostrum / Q000276:immunology; D004927:Escherichia coli Infections / Q000517:prevention & control / Q000662:veterinary*; D005260:Female; D005759:Gastroenteritis / Q000517:prevention & control / Q000662:veterinary*; D007114:Immunization / Q000662:veterinary*; D007074:Immunoglobulin G / Q000096:biosynthesis; D011247:Pregnancy; D013552:Swine; D013553:Swine Diseases / Q000517:prevention & control*
D000992:Antitoxins; D007074:Immunoglobulin G; D002772:Cholera Toxin