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.