EXPRESSION AND FUNCTIONAL-CHARACTERIZATION OF RECOMBINANT CHICKEN INTERFERON-GAMMA

A cDNA encoding chicken interferon-gamma (chIFN-gamma) was cloned from a CD4(+) T-cell hybridoma by reverse transcription-polymerase chain r eaction (RT-PCR) and expressed in Escherichia coli, COS-and CEC-32 fib roblast cell lines. In general, recombinant chicken IFN-gamma (rchIFN- gamma) expressed in the COS-and CEC-32 cell lines showed high bioactiv ity in vitro. The kinetics of IFN-gamma gene expression were examined in concanavalin A (Con A)-activated spleen lymphocytes by Northern blo t and RT-PCR. IFN-gamma mRNA was detected as early as 30 min after Con A activation, reached peak expression at 2 h and then decreased start ing at 4 h post Con A activation. A rabbit serum made to a synthetic p eptide of IFN-gamma immunoprecipitated a 60 kDa E. coli maltose-bindin g fusion protein of recombinant IFN-gamma (MBP-IFN) and a 26-27 kDa se creted protein from COS cells and Con A-activated spleen cells. IFN-ga mma inhibited vesicular stomatitis virus (VSV) mediated cytotoxicity o f chicken embryonic fibroblast (CEF) cells and upregulated the express ion of many macrophage cell surface antigens, including class I and cl ass Il major histocompatibility complex (MHC) proteins. These results show that chicken IFN-gamma possesses anti-viral activity and immunore gulates macrophage activities. (C) 1997 Elsevier Science B.V.