Development of DNA-designed avian IgY antibodies for quantitative determination of bovine interferon-gamma.

Interferon-gamma (IFN-γ), a cytokine produced by sensitized T lymphocytes, is one of the key elements in defining T helper 1 lymphocyte immune responses. Quantitative evaluation of IFN-γ expression could provide an important analytical tool for measurement of cell-mediated immunity and investigating immune responses to infectious diseases. Method of DNA-designed avian IgY antibodies was used for production of monospecific polyclonal antibodies that allows quantification of the recombinant bovine IFN-γ protein. IFN-γ cDNA was subcloned and expressed in mammalian expression plasmid (pcDNA3.1(+)) under the control of the human cytomegalovirus promoter. Chickens were immunized by plasmid DNA, and egg yolk antibodies extracted from eggs were collected after immunization. IgY-specific antibodies were evaluated by an antigen capture enzyme-linked immunosorbent assay (ELISA) using recombinant IFN-γ. Based on the results, developed bovine IFN-γ capture ELISA could detect up to 1 ng/ml of IFN-γ by 64-fold diluted IgY. Monospecific anti-bovine IFN-γ antibodies generated in chickens are useful for quantifying different concentrations of recombinant bovine IFN-γ, which is expressed in cell culture.