Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 31, 1995
Publication Date: N/A
Interpretive Summary: Interferons are protein hormones secreted by lymphocytes in response to bacteria, virus and parasites. These proteins play an important role in modulating host immune response to infections. Therefore, studying the function and biochemistry of interferon is crucial in our understanding of avian diseases such as coccidiosis. In order to better understand the function of chicken interferon, ARS scientists isolated interferon from chicken lymphocytes and showed that chicken interferon activates macrophages. The results will enhance our understanding of how interferon enhances host protective immunity to coccidian parasites.
Conditioned medium (CM) containing immune interferon (IFN) activity was prepared by stimulating spleen lymphocytes obtained from inbred SC chickens with 10 ug concanavalin A (Con A) for 48 hours. Pretreatment of spleen cells with monoclonal antibody (mAb) against CD4, but not CD8, abrogated IFN production suggesting that CD4+ lymphocytes are responsible for immune IFN production. Immune IFN was purified 25-fold from Con A CM using controlled-pore glass column chromatography resulting in an increase in specific antiviral activity from 7 to 3290 units/mg. Partially purified immune IFN retained antiviral and macrophage-activation factor (MAF)- like activities. Normal peripheral blood macrophages, when cultured in the presence of partially purified immune IFN, showed a dose-dependent increase in cell surface major histocompatibility complex (MHC) class II antigen expression by flow cytometry. Northern blot analysis of mRNA obtained from IFN-treated macrophages showed a concomitant increase in class II gene expression. This effect was more obvious in cells induced for 48 hours than in those induced for 24 hours. These results strongly suggest the existence of an avian homologue of the MAF-like activity.