Submitted to: Vaccine
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/25/2006
Publication Date: 11/13/2006
Citation: Dalloul, R.A., Lillehoj, H.S., Klinman, D.M., Ding, X., Min, W., Heckert, R.A., Lillehoj, E.P. 2006. In ovo administration of CpG oligodeoxynucleotides and the recombinant microneme protein MIC2 protects against Eimeria infections . Vaccine 23:3108-3113. Interpretive Summary: Coccidiosis is an intestinal parasitic disease caused by several distint species of Eimeria parasites. Drugs have been traditionally used to control coccidiosis. However, with increasing concerns by the consumers on the development of drug resistance, the development of alternative control strategies against avian coccidiosis is needed. In this paper, ARS scientists in collaboration with non ARS scientists demonstrate a novel immunomodulating compound which consists of novel short oligodeoxynucleotides containing unmethylated CpG motifs (CpG ODNs). CpG ODNs enhanced host intestinal immunity and significantly improved disease resistance against avian coccidia in chickens. These results clearly established the ability of CpG ODN to improve protective immunity against poultry parasitic disease. The information will benefit poultry vaccine companies.
Technical Abstract: We have previously demonstrated that short oligodeoxynucleotides containing unmethylated CpG motifs (CpG ODNs) exert a positive effect on weight loss and oocyst shedding associated with Eimeria infection when injected in vivo. The present work investigated the effects of in ovo vaccination with CpG ODNs and an Eimeria recombinant microneme protein (MIC2), alone or in combination, on susceptibility to coccidiosis. In ovo injection of CpG ODNs alone enhanced resistance to experimental E. acervulina infection as best exemplified by reduced oocyst shedding. Two CpG ODNs reduced the oocyst load, but did not affect weight gain. When co administered with the recombinant microneme protein, both ODNs reduced oocyst shedding; however, only ODN D19 plus MIC2 consistently improved weight gain. Vaccinating with ODN 2006 or MIC2 protein curtailed oocyst shedding but did not enhance weight gain in E. tenella infected birds. Co administration of CpG ODN and MIC2 did not have an additive effect in reducing the oocyst output; however, it resulted in the highest and lowest Ab response before and after E. tenella infection, respectively. Collectively, CpG ODNs administered in ovo demonstrated immunoenhancing and adjuvant effects following Eimeria infections.