Pili in microspheres protect rabbits from diarrhoea induced by E. coli strain RDEC-1.
We tested whether pilus proteins of rabbit diarrhoeagenic Escherichia coli (RDEC-1), incorporated into biodegradable microspheres, could function as safe and effective oral immunogens in the rabbit diarrhoea model. The RDEC-1 adhesin, AF/R1, incorporated into poly(D,L-lactide-co-glycolide) microspheres, was administered intraduodenally. Vaccinated and unvaccinated rabbits were challenged with RDEC-1 and killed 1 week later. Vaccination with AF/R1 in microspheres did not cause diarrhoea or weight loss. After challenge, rabbits given AF/R1 in microspheres, in contrast to unvaccinated animals, remained in good health. RDEC-1 attachment to caecal epithelium of vaccinated rabbits was reduced (p = 0.02), whereas numbers of RDEC-1 in intestinal fluids were little affected. Also, in vaccinated animals, biliary anti-AF/R1 IgA levels were increased, and AF/R1-induced blast-cell transformation was vigorous in spleen cell cultures. We conclude that vaccination with AF/R1 in microspheres was safe and protected rabbits against RDEC-1 disease, probably by interfering with adherence of the bacteria to the intestinal mucosa. The interference might have been due to the presence of specific antibodies secreted in bile.
McQueen
C E
CE
Department of Gastroenterology, Walter Reed Army Institute of Research, Washington, DC 20307.
Boedeker
E C
EC
Reid
R
R
Jarboe
D
D
Wolf
M
M
Le
M
M
Brown
W R
WR
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000276:immunology; D001422:Bacterial Adhesion; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology / Q000633:toxicity; D001646:Bile / Q000276:immunology; D001835:Body Weight; D002432:Cecum / Q000382:microbiology; D003967:Diarrhea / Q000382:microbiology / Q000517:prevention & control*; D004339:Drug Compounding; D004926:Escherichia coli / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000382:microbiology / Q000517:prevention & control*; D022361:Escherichia coli Vaccines; D010861:Fimbriae, Bacterial / Q000276:immunology*; D007413:Intestinal Mucosa / Q000382:microbiology; D008213:Lymphocyte Activation; D008863:Microspheres; D010581:Peyer's Patches / Q000276:immunology; D011817:Rabbits; D014611:Vaccination / Q000379:methods
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D022361:Escherichia coli Vaccines