Filia, GursimranKaur, Gurleen2021-10-122021-10-122019https://krishikosh.egranth.ac.in/handle/1/5810176919T1799The present investigation was carried out to diagnose bovine tuberculosis and to characterizse the tuberculous lesions. Tissue samples from 20 cases suspected for bTB along with five healthy tissue samples were used for the study. Ziehl- Neelsen staining was done and AFB were detected in 13 samples. Extraction of DNA from tissue samples was carried out and subjected to IS6110 PCR using INS1/INS2 primers specific for MTC with band size at 245 bp. Eleven samples were found positive by IS6110 PCR. For the differentiation of species of MTC, gyrB PCR-RFLP was performed. All the PCR positive samples showed presence of M.bovis subsp. bovis as the major causative agent of bTB. Histopathologically, eleven samples showed the presence of characteristic granulomas and majority of the granulomas observed were encapsulated with areas of central necrosis and calcification. IHC was performed on samples for detection of MTC antigen. Thirteen of the total samples were positive by IHC. Cytokines (IFN-γ, TNF-α, IL-10, IL-4, IL-13) were estimated in tissue homogenates by ELISA. A significant increase in the pro-inflammatory cytokine levels was observed in TB positive samples as compared to that of anti-inflammatory cytokine levels. However, both pro-inflammatory and anti-inflammatory cytokines levels along with IL-10 (immune-modulator) were increased in TB positive animals as compared to that of healthy animals. Thus, the present study showed that M. bovis is the main cause of bTB and cytokines play a major role in immunopathogenesis of bTB.EnglishThesis