Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 1, 2002
Publication Date: October 12, 2002
Citation: Zhou, H., Lillehoj, H.S., Lamont, S.J. 2003. Association of chicken interferon-y genotype and protein level with antibody response kinetics. Avian Diseases. 46:869-876.
Interpretive Summary: Interferon (IFN)-gamma is a soluble substance which is secreted by T lymphocytes after these cells encounter foreign antigens. Since T lymphocytes are important effect cells mediating cell-mediated immune responses, the assessment of IFN-gamma production during infection has been used as a major indicator of host immunity. In this study, scientists at Iowa State University and ARS scientists collaborated to develop an enzyme-based immunoassay to measure chicken IFN-gamma production and used this assay to demonstrate the role of chicken IFN-gamma in antibody production in different genetic lines of chickens. The results provide important information on the role of host genetic background in controlling host immune responses.
Although previous studies have demonstrated an association between interferon-gamma (IFN-gamma) promoter genotype and antibody response in chickens, the protein levels that may mediate such a gene-trait association have not been determined. The objective of this study was to evaluate the correlation of circulating IFN-gamma levels with both the IFN-gamma promoter polymorphisms and with antibody response, in order to evaluate the role of IFN-gamma protein in mediating genetic control of antibody response in chickens. Serum IFN-gamma protein level and antibody response to sheep erythrocytes (SRBC) and Brucella abortus antigens, and Salmonella enteritidis (SE) vaccine were measured in an intercrossed F2 population derived from inbred lines. Single nucleotide polymorphism in the IFN-gamma promoter region was associated with IFN-gamma protein expression after both primary and secondary immunizations. Higher IFN-gamma protein level was associated with increased maximum level and decreased time to reach maximum secondary antibody response to SRBC and also with higher antibody level to SE. These results suggest that one of the mechanisms by which promoter polymorphism of IFN-gamma affects antibody production in chickens may involve IFN-gamma protein secretion in the circulation.