Mycobacterial antibodies against BCG and M.tuberculosis H37RA do not recognize pathogenic M.tuberculosis cells but do recognize their cytoplasmic constituents

The humoral immune response against mycobacterial pathogens and BCG vaccine is still poorly understood. It is not known if antibodies raised against BCG react with all pathogenic M. tuberculosis strains. The question arose during the development of a tuberculosis detection system based on antibodies. It was found that antibodies raised against cells of avirulent TB strain H37Ra and against whole sonicates of BCG do not react consistently with whole cells of pathogenic TB strains and very poorly with whole BCG cells. These antibodies; however, react very well with the internal components of the BCG cell [i.e. A 60 and cytoplasmic constituents]