Development and applications of a monoclonal antibody against caprine interferon-gamma

Background Interferon-gamma (IFN-gamma) is an important mediator of type I immune response and has antiviral, immunoregulatory and anti-tumor properties, plays a wide range of roles in inflammation and autoimmune diseases. The aim of this study was to obtain monoclonal antibody (mAb) against caprine IFN-gamma by immunizing of BALB/c mice with the purified rIFN-gamma. Results Recombinant caprine IFN-gamma was expressed in Escherichia coli strain BL21 (DE3) and monoclonal antibodies against caprine IFN-gamma were produced by immunizing of BALB/c mice with rIFN-gamma. One hybridoma secreting mAb was screened by enzyme-linked immunosorbent assay (ELISA) which was designated as 2C. MAb secreted by this cell line were analyzed through ELISA, western blot and application of the mAb was evaluated by immunofluorescence analysis using goat lip tissues infected with Orf virus. ELISA analysis revealed that mAb 2C can specifically recognize rIFN-gamma protein and culture supernatant of goat peripheral blood mononuclear cells (PBMCs) stimulated by concanavalin A (Con A) but cannot recognize the fusion tag protein of pET-32a. Western blot analysis showed that mAb 2C can specifically react with the purified 34.9 kDa rIFN-gamma protein but does not react with the fusion tag protein of pET-32a. Immunofluorescence results demonstrated that mAb 2C can detect IFN-gamma secreted in histopathological sites of goats infected with Orf virus. Conclusions A caprine IFN-gamma-specific mAb was successfully developed in this study. Further analyses showed that the mAb can be used to detect IFN-gamma expression level during contagious ecthyma in goats.