Deletion of the 19kDa antigen does not alter the protective efficacy of BCG

Abstract Expression of the Mycobacterium tuberculosis 19kDa lipoprotein in saprophytic mycobacteria has been found to reduce their ability to prime a protective response to subsequent virulent challenge in the mouse model. The present study was designed to test whether 19kDa expression has an analogous detrimental effect on the efficacy of BCG vaccination. In contrast to the results in saprophytes, neither overexpression of the 19kDa antigen, nor deletion of the endogenous 19kDa gene altered the ability of BCG to protect against M. tuberculosis challenge in a mouse model.