Generation of Recombinant GroEL (HSP60) of Bacillus Anthracis in Heterologous System E. coli and Evaluation of Its Humoral Immune Response in Mouse Model

Anthrax, a disease of public health as well as bio-warfare potential is caused by Gram positive, non-motile and spore forming Bacillus Anthracis. Bacteraemia and toxaemia of B. anthracis is responsible to cause lethality in anthrax-infected host. In this study, GroEL (HSP60) gene was cloned in pET28a+ vector and expressed in heterologous system E. coli. Over expressed recombinant GroEL was purified by IMAC chromatography and analysed on 10% SDS-PAGE. In western blot analysis, the rGroEL reacted with mouse anti-his antibody and anti-B. anthracis Sterne mouse serum. The immunogenicity of GroEL with aluminium hydroxide was evaluated in BALB/c mouse model. The endpoint titer of anti-rGroEL circulating antibodies in mouse serum was found high by indirect ELISA after first and second booster doses. IgG1 and IgG2b isotypes were found dominating in comparison to other isotypes. Humoral immune response generated by rGroEL indicated that it is immuno-dominant antigen of B. anthracis, which could be further evaluated as a subunit vaccine candidate against anthrax.