Submitted to: Annual Conference on Vaccine Research
Publication Type: Proceedings
Publication Acceptance Date: 3/26/2005
Publication Date: 5/5/2005
Citation: Dalloul, R.A., Lillehoj, H.S., Klinman, D.M., Ding, X., Min, W., Heckert, R.A., Lillehoj, E.P. 2005. Cpg oligodeoxynucleotides co-administered with the microneme protein mic2 protect against eimeria infections.. Annual Conference on Vaccine Research 64. Interpretive Summary: Coccidiosis is caused by several different Eimeria parasites which infect the intestine of susceptible host. Avian coccidiosis causes serious economic losses to US poultry industry and there is a need for the development non-drug-dependant control strategy against this infection. In this communication, ARS scientists, in collaboration with scientists at University of Maryland and US Food and Drug Administration have discovered new oligopeptide immunomodulators which enhance gut immunity in chickens. These scientists have identified new short synthetic oligodeoxynucleotide sequences containing unmethylated CpG motifs (CpG ODNs) which stimulate chicken innate immunity and enhance disease resistance against avian coccidiosis. The results of this study will provide basic groundwork for utilization of ODNs as immunomodulators for poultry disease control.
Technical Abstract: Short synthetic oligodeoxynucleotides containing unmethylated CpG motifs (CpG ODNs) were previously shown to 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 chicken 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.