PROTECTION AGAINST ENTERIC COLIBACILLOSIS IN PIGS SUCKLING ORALLY VACCINATED DAMS - EVIDENCE FOR PILI AS PROTECTIVE ANTIGENS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 42  (2) , 173-177
Abstract
Pregnant gilts were vaccinated orally with Escherichia coli that produced pilus antigens K99 or 987P. The vaccines were live or dead enterotoxigenic E. coli (ETEC) or a live rough non-ETEC strain which has little ability to colonize pig intestine. Pigs born to the gilts were challenge exposed orally with K99+ or 987P+ ETEC, which did not produce heat-labile enterotoxin or flagella and which produced somatic and capsular antigens different from those of the vaccine strains. Control gilts had low titers of serum and colostral antibodies against pilus antigens and their suckling pigs frequently had fatal diarrhea after challenge exposure. Serum antibody titers against pilus antigens of the vaccine strains increased in the gilts after vaccination with live ETEC and the colostral antibody titers of these gilts were higher than those of controls. Pigs suckling such vaccinated gilts were more resistant than controls to challenge exposure by ETEC of the homologous pilus type. This resistance was not attained when vaccine and challenge strains were of different pilus types and it could not be attributed to enterotoxin neutralization by colostrum. In contrast to the live ETEC vaccines given to the pregnant gilts, the live rough non-ETEC and dead ETEC vaccines stimulated little or no production of antibody against pili, and the pigs born of these vaccinated gilts remained highly susceptible to challenge exposure. Pili can be protective antigens in oral ETEC vaccines. In the system reported, protection depended on living bacteria for the production of pilus antigens in vivo or for the transport of pilus antigens across intestinal epithelium.

This publication has 18 references indexed in Scilit: