Mycobacterium Tuberculosis ESAT6 Products

ESAT-6 (6-kDa early secretory antigenic target) from Mycobacterium tuberculosis H37Rv (ATCC 27294) (1) is a secreted tubercular protein that forms a dominant target for cell-mediated immunity in the early phase of infection (2). The deduced amino acid sequence indicates a molecular mass of 10 kDa. It is present in M. tuberculosis, virulent strains of M. bovis, and in M. flavescens, M. kansasii, M. marinum, and M. szulgai, but not in avirulent M. bovis BCG substrains (3).