Recombinant fusion 24.4 kDa protein based in house ELISA for serodiagnosis of paratuberculosis

Paratuberculosis is a zoonotic chronic infectious enteric disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis. ELISA based assay is ideal and sensitive for the screening of sera from infected animals. In this study, we use Map recombinant fusion 24.4 kDa protein developed by fusing the epitopic region of 300bp each from locus tag Map 0862 and locus tag Map 1637 to produce an in-house ELISA. The recombinant fusion 24.4 kDa was purified by single step chromatography using Ni-NTA Agarose. The recombinant fusion 24.4 kDa was reacted with anti- recombinant fusion 24.4 kDa antibodies as well as bovine and sheep sera infected with Map on western blot. A total of 106 animals samples were screened by commercial kit followed by Map recombinant fusion 24.4 kDa protein-based in-house ELISA. In-house ELISA using well-characterized sera (n=106) sample from sheep and bovine yielded a sensitivity of 85% and the specificity of 84.62%. The recombinant fusion 24.4 kDa used in the present study will prove useful as a diagnostic reagent in an in-house ELISA test.