Cloning, sequencing, and expression of interferon-gamma from elk in North America

Eradication of Mycobacterium bovis relies on accurate detection of infected animals, including potential domestic and wildlife reservoirs. Available d iagnostic tests lack the sensitivity and specificity necessary for accurate detection, particularly in infected wildlife populations. Recently, an in vitro diagnostic test for cattle which measures plasma interferon-gamma (IF N-gamma) levels in blood following in vitro incubation with M. bovis purifi ed protein derivative has been enveloped. This test appears to have increas ed sensitivity over traditional testing. Unfortunately, it does not detect IFN-gamma from Cervidae. To begin to address this problem, the IFN-gamma ge ne from elk (Cervus elaphus) was cloned, sequenced, expressed, and characte rized. cDNA was cloned from mitogen stimulated peripheral blood mononuclear cells. The predicted amino acid (aa) sequence was compared to known sequen ces from cattle, sheep, goats, red deer (Cervus elaphus), humans, and mice. Biological activity of the recombinant elk IFN-gamma (rElkIFN-gamma) was c onfirmed in a vesicular stomatitis virus cytopathic effect reduction assay. Production of monoclonal antibodies to IFN-gamma epitopes conserved betwee n ruminant species could provide an important tool for the development of r eliable, practical diagnostic assays for detection of a delayed type hypers ensitivity response to a variety of persistent infectious agents in ruminan ts, including M, bovis and Brucella abortus. Moreover, development of these reagents will aid investigators in studies to explore immunological respon ses of elk that are associated with resistance to infectious diseases.