Abstract

Bovine Tuberculosis an important infectious disease of cattle in developing countries which needs an urgent requirement for effective strategies for disease eradication. The spread of Bovine Tuberculosis also poses a human health risk. We assessed the possibility of using the quantification of IFN-ɣ-producing CD4+ lymphocytes by Cytokine Flow Cytometric analysis of intracellular IFN-ɣ expression for discrimination of naturally infected cattle "which is confirmed by isolation of M.bovis" from vaccinated animals with BCG vaccine. The obtained results showed that significant numbers of IFN-γ-expressing CD4+ T-cells were detected following culture of heparinized blood from M. bovis-infected animals with purified protein derived from M.bovis (PPD-B), the BCG-vaccinated animals had a significant low number of CD4+ T lymphocytes expressing IFN-ɣ compared with naturally M.bovis-infected animals. It is concluded that this assay could allow an accurate diagnosis of M. bovis and allow the discrimination of BCG-vaccinated cattle from infected cattle, which can evaluate the recent prepared vaccine used against tuberculosis in cattle. So it is recommended to evaluate this discrimination technique on larger number of animals to deduce dependable results

Key words: Bovine Tuberculosis, BCG vaccine, T-lymphocytes, Gamma Interferon