Over-expression of superoxide dismutase obliterates the protective effect of BCG against tuberculosis by modulating innate and adaptive immune responses

► Assessment of protective efficacy of rBCG over-expressing SOD-A against TB. ► Over-expression of SOD in BCG completely abrogates protection of BCG vaccine. ► rBCG infected macrophages show reduction in apoptosis and microbicidal potential. ► Vaccination with rBCG skews the immune responses towards Th2 type. ► rBCG vaccination fails to generate effective multi-functional CD4 T cell response.