Recombinant Proteins based ‘rELISA’ Field Validation for Differential Diagnosis of Johne’s Disease in Goats

Abstract

Background: Johne’s disease (JD), caused by Mycobacterium avium subspecies paratuberculosis (MAP), is spreaded worldwide in domestic livestock. It is very clear that JD control program having tedious complications so, only ‘Test and cull’ and ‘vaccination’ strategies are key components in JD control program. ‘Test and cull’ policy is not feasible in Indian condition due to religious beliefs However, vaccination interferes with the immunological tests used for screening of infected and vaccinated (Healthy) animals. Thus, a test that can differentiate between infected and vaccinated animals (DIVA) is needed before implementation of vaccination program. Methods: Herein, we evaluated two in-house ELISA tests i.e., recombinant proteins-based ELISA (rELISA); developed by using six MAP specific recombinant culture filtrate proteins and indigenous ELISA (i_ELISA); developed using whole-cell protoplasmic MAP antigens for their potential. Sera collected from goats under ‘infected’, ‘healthy and vaccinated’ and ‘healthy and non-vaccinated’ groups were tested by both the tests. Result: On analyzing the anti-MAP antibodies level detected by both the ELISAs and anti-MAP antibodies against secretary proteins only detected in i_ELISA, it was concluded that rELISA can differentiate healthy, vaccinated and infected goats, if used in-combination with i_ELISA. Therefore, recombinant proteins based rELISA has potential to be considered as companion tool for future diagnostic for successful implementation of JD vaccination control program.