Submitted to: International Conference on Mycobacterium bovis
Publication Type: Abstract Only
Publication Acceptance Date: 8/22/2005
Publication Date: 8/22/2005
Citation: Harrington, N., Waters, W.R., Surujballi, O., Prescott, J. 2005. Development of a Multispecies Real-time RT-PCR Whole Blood Assay to detect Interferon-gamma Response to Mycobacterial Antigens and Evaluation in Mycobacterium bovis-infected elk (cervus elaphus)[abstract]. International Conference on Mycobacterium bovis. p. 73. Interpretive Summary:
Technical Abstract: In North America, wild elk (Cervus elaphus) and white-tailed deer (Odocoileus virginianus) can be reservoirs for Mycobacterium bovis and are implicated in the maintenance and transmission of tuberculosis to other wildlife, to cattle, and to humans. Current diagnostic tests lack sufficient sensitivity and specificity for accurate detection of infected wildlife populations. In other species, methods which assay the in vitro production of gamma interferon (IFN-gamma) in response to mycobacterial antigens by ELISA or ELISPOT are more sensitive than other tests for tuberculosis. Unfortunately, these assays do not react with many non-traditional domestic and wildlife species. Furthermore, these protein based assays are difficult to develop because of a lack of immunological reagents. This report describes the development of a simple and rapid multispecies whole blood assay for the quantitative measurement of IFN-gamma mRNA response to M. bovis antigens by real-time reverse transcriptase (RT) polymerase chain reaction (PCR). The whole blood assay was evaluated to determine its potential usefulness in detecting M. bovis-infection using experimentally infected elk and was compared to other cellular assays including a commercial cervid IFN-gamma ELISA (Cervigam). In response to mycobacterial antigens, the production of IFN-gamma mRNA correlated well with lymphocyte blastogenesis and the production of the IFN-gamma protein as detected by ELISA. This assay will be particularly relevant for the diagnosis of tuberculosis in wildlife/non-traditional species for which protein-based immunoassays are not yet available.