Journal of Clinical and Cellular Immunology
Open Access
ISSN: 2155-9899
ISSN: 2155-9899
Gaber S Abdellrazeq
Alexandria University, Egypt
Posters-Accepted Abstracts: J Clin Cell Immunol
Introduction: Control of bovine tuberculosis (bTB) continues to be a problem world-wide because of difficulties in identifying infected animals at all stages of infection. The use of the IFN-�³ release assays (IGRA) as an ancillary test with the tuberculin skin tests has improved the ability to identify infected animals. However, infected animals may still be missed. Objective: The objective of the present study was to evaluate a rapid flow-cytometric approach based on intracellular cytokine staining as an alternative readout. Materials & Methods: Antigen-specific cells producing IFN-�³ were identified after a 6 hour stimulation with PPD-B, PPD-A and ESAT-6/CFP-10. Defined groups of animals naturally infected with Mycobacterium bovis (Mbv), animals infected with non-tuberculous mycobacteria (NTM) and uninfected control animals were analyzed to evaluate the sensitivity and specificity of the optimized assay. Both antemortem and postmortem diagnostic tests were carried out to verify the status of infection. Results: We show that IFN-�³ is induced in T cells from whole blood samples from cattle infected with Mbv 6 hours post stimulation with PPD-B, PPD-A and ESAT-6/CFP-10, whereas non-infected animals did not respond. Four color flow cytometric analysis demonstrated responding cells were CD45R0+CD69+CD4+ memory T cells. Moreover, induction of IFN-�³ in response to ESAT-6/CFP-10 can be used to distinguish between cattle infected with Mbv and cattle exposed to NTM. Conclusion: Although further studies are needed, the results indicate that detection of intracellular IFN-�³ may represent an important alternative approach with the potential for improved detection of cattle secreting IFN-�³ below levels of detection in culture medium.