Padmavathy, C.Vijayarani, K.Kumanan, K.Thangavelu, A.Srithar, A.TANUVAS2018-07-232018-07-232018-07http://krishikosh.egranth.ac.in/handle/1/5810061559TNV_IVJ_2018_95(7)45-49Paratuberculosis caused by Mycobacterium avium subsp. paratuberculosis is a chronic incurable infection with worldwide prevalence due to the limitations in the early diagnosis and lack of effective vaccine. There is a need to identify the antigen, which could be candidates for vaccines with universal ef cacy and for speci c early diagnosis of paratuberculosis. A novel ESAT gene family with homology to ESAT6 was identi ed among mycobacterial species encoding ESAT6 Like proteins. Among the genes of this family ESXO, was found to be immunodominant and protects against M. tuberculosis. MAP 4_2856 is an ortholog ESXO gene of M. avium subsp. paratuberculosis encoding putative ESAT6 like protein. In this study ESXO gene was cloned in pET 21b vector and expressed in E.coli. Strong immuno reactivity with bovine anti M. avium subsp. paratuberculosis antibodies in immunoblot analysis supports for an immunodominant antigen candidate for use.enVeterinary ScienceArticle