1a.Objectives (from AD-416)
Evaluate the immunomodulatory effect of Pfizer's proprietary adjuvants in a poultry disease model.
1b.Approach (from AD-416)
Investigate the efficacy of Pfizer's new adjuvant in formulation in recombinant vaccine.
This trust agreement with the Pfizer Animal Health was established in 2007 to develop a new strategy for delivering recombinant poultry vaccines against avian coccidiosis. Using novel immunomodulators which are patented by the Pfizer Animal Health, various delivery methods to activate local immunity against poultry pathogens were investigated. 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 in ovo 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. However, 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-G were seen in the intestinal tissues of animals given profilin plus QCDC compared with the profilin-only or QCDC-only groups. This study demonstrated an adjuvant effect of QCDC on body weight gain and intestinal cytokine responses following in ovo vaccination of chickens with an Eimeria profilin vaccine. This information will be used for development of an in ovo vaccination strategy against avian coccidiosis and other enteric diseases of poultry. This project is being monitored by monthly teleconferences and frequent meetings at the national and international meetings where both parties attend.