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

Expression of the Mycobacterium tuberculosis 19kDa lipoprotein in saprophyt ic mycobacteria has been found to reduce their ability to prime a protectiv e response to subsequent virulent challenge in the mouse model. The present study was designed to test whether 19kDa expression has an analogous detri mental effect on the efficacy of BCG vaccination. In contrast to the result s 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. (C) 2001 Harcourt Publishers L td.