MTSA-10, the product of the Rv3874 gene of Mycobacterium tuberculosis, elicits tuberculosis-specific, delayed-type hypersensitivity in guinea pigs.

In a search for new skin test reagents specific for tuberculosis, we found that the antigen encoded by gene Rv3874 of Mycobacterium tuberculosis elicited delayed-type hypersensitivity in M. tuberculosis-infected guinea pigs but not in control animals immunized with Mycobacterium bovis bacillus Calmette-Guérin (BCG) or Mycobacterium avium. The antigen, which was named MTSA-10 (for M. tuberculosis-specific antigen 10), is a prime candidate for a component of a new tuberculin that will allow discrimination by a skin test of latent M. tuberculosis infection from vaccination with BCG or from sensitization with environmental, nontuberculous mycobacteria.