Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 28, 2011
Publication Date: April 5, 2011
Citation: Lee, S.H., Lillehoj, H.S., Jang, S., Lee, K., Yancy, R.J., Dominowski, P. 2011. Effects of novel adjuvant complex/Eimeria profilin vaccine on intestinal host immune responses against live E. acervulina challenge infection. Vaccine. 28(39):6498-6504. Interpretive Summary: Avian coccidiosis is an economically important intestinal disease caused by multiple species of Eimeria. Due to the increasing emergence of drug-resistant coccidia in commercial production settings, alternative strategies are sought. Although there is a growing reliance on the use of Eimeria parasite vaccines for coccidiosis control, live vaccines pose the risk of unintended infection under the immunosuppressive conditions associated with high-density commercial poultry rearing conditions. On the other hand, while subunit protein and DNA vaccines do not present the possibility of field infections, both are of limited immunogenicity and there is a lack of suitable immunoenhancing adjuvants for their use in poultry. To address these challenges, ARS scientists teamed with Pfizer Animal Health scientists to demonstrate the efficacy of a novel adjuvant composed of Quil A, cholesterol, dimethyl dioctadecyl ammonium bromide, and Carbopol (QCDC) on protective immunity against avian coccidiosis following immunization with an Eimeria recombinant protein. The results of this collaboration showed that broiler chickens subcutaneously immunized with Eimeria profilin emulsified with QCDC showed enhanced body weight gain and reduced gut lesions. In summary, this study provides the first evidence to document the immunoenhancing activities of QCDC adjuvant in poultry and this new knowledge will enhance our ability to develop novel vaccines against poultry diseases.
Technical Abstract: The effects of a novel adjuvant; composed of Quil A, cholesterol, dimethyl dioctadecyl ammonium bromide, and Carbopol (QCDC), on protective immunity against avian coccidiosis following immunization with an Eimeria recombinant protein were determined. Broiler chickens were subcutaneously immunized with isotonic saline (control), Eimeria recombinant profilin alone, or profilin emulsified with QCDC at 1 and 7 days post-hatch and orally challenged with live E. acervulina at 7 days following the last immunization. Body weight gains, gut lesion scores, fecal oocyst outputs, profilin serum antibody titers, lymphocyte proliferation, and intestinal cytokine transcript levels were assessed as measures of protective immunity. Chickens immunized with profilin plus QCDC showed increased body weight gains and decreased intestinal lesion scores compared with the profilin only or control groups. However, no differences were found in fecal oocyst shedding among the three groups. Profilin serum antibody titers and antigen-induced peripheral blood lymphocyte proliferation in the profilin/QCDC group were higher compared with the profilin only or control groups. Finally, while immunization with profilin alone or profilin plus QCDC uniformly increased the levels of intestinal transcripts encoding, all cytokines examined (IL-1ß, IL-10, IL-12, IL-15, IL-17A, and IFN-') compared with the control group, transcripts for IL-10 and IL-17A were further increased in the profilin/QCDC group compared with the profilin only group. In summary, this study provides the first evidence to document the immunoenhancing activities of QCDC adjuvant in poultry.