AVIAN GENOMIC AND IMMUNOLOGIC APPROACHES FOR CONTROLLING MUCOSAL PATHOGENS
Title: Embryo vaccination of chickens using a novel adjuvant formulation stimulates protective immunity against Eimeria maxima infection
Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 5, 2011
Publication Date: June 1, 2011
Citation: Lee, S.H., Lillehoj, H.S., Jang, S., Hong, Y., Min, W., Lillehoj, E., Yancy, R.J., Dobinowski, P. 2011. Embryo vaccination of chickens using a novel adjuvant formulation stimulates protective immunity against Eimeria maxima infection. Vaccine. 28(49):7774-7778.
Interpretive Summary: Development of molecular vaccines in general suffers from a weak immunogenicity associated with subunit antigen of pathogens. For example, in spite of encouraging results, immunization with recombinant proteins has, in general, shown limited success in stimulating broad-spectrum protective immunity against multiple coccidia species due to their low antigenicity and restricted expression during the parasite life cycle. In this study, ARS scientists collaborated with private industry scientists to demonstrate the immunoenhancing effects of novel formulation which is a combination of Quil A/cholesterol/DDA/Carbopol (QCDC) adjuvant on an experimental recombinant coccidia vaccine. In this study, novel vaccine formulation was given in ovo since this is used in commercial applications worldwide throughout the poultry industry. The results showed that Eimeria profilin plus QCDC increased body weight gain such that it was equal to the uninfected controls. In summary, this study demonstrates an adjuvant effect of QCDC on enhancing immunogenicity of a peptide vaccine and this information will help animal vaccine industry to formulate a better vaccine for poultry.
Our previous study demonstrated that chickens immunized subcutaneously with an Eimeria recombinant profilin protein vaccine emulsified in a Quil A/cholesterol/DDA/Carbopol (QCDC) adjuvant developed partial protection against experimental avian coccidiosis compared with animals immunized with profilin alone. Because in ovo vaccination is presently used in commercial applications worldwide throughout the poultry industry, the current study was undertaken to investigate chicken embryo vaccination with profilin plus QCDC adjuvant. Eighteen day-old embryos were immunized with isotonic saline (control), profilin alone, QCDC alone, or profilin plus QCDC, and orally challenged with live E. maxima at 7 days post-hatch. Body weight gain, fecal oocyst output, and intestinal cytokine transcript levels were assessed as measures of protective immunity. While immunization with profilin alone or QCDC alone did not alter body weight gain of infected chickens compared with the saline control group, vaccination with profilin plus QCDC increased body weight gain such that it was equal to the uninfected controls. Immunization with profilin plus QCDC also reduced fecal oocyst shedding compared with unimmunized controls, although in this case QCDC failed to provide an adjuvant effect since no difference was observed between the profilin-only and profilin/QCDC groups. Finally, increased levels of transcripts encoding IL-1ß, IL-15, and IFN-' were seen in the intestinal tissues of animals given profilin plus QCDC compared with the profilin-only or QCDC-only groups. In summary, this study demonstrates an adjuvant effect of QCDC on body weight gain and intestinal cytokine responses following in ovo vaccination of chickens with an Eimeria profilin vaccine.