Human CD8+ T cells recognize epitopes of the 28-kDa hemolysin and the 38-kDa antigen of Mycobacterium tuberculosis.

Mycobacterium tuberculosis antigens that are recognized by human CD8+ T cells are potentially important vaccine target molecules. We used a motif-based strategy to screen selected proteins of M. tuberculosis for peptides predicted to bind to human leukocyte antigen (HLA)-A*0201. We identified two 10 amino acid peptides that elicited cytolytic T lymphocyte activity and interferon-gamma production by CD8+ T cells from HLA-A*0201+ healthy tuberculin reactors. These peptides were derived from the 38-kDa antigen and the 28-kDa hemolysin, the latter being a novel target for CD8+ T cells. We speculate that hemolysins may alter the phagosomal membrane surrounding intracellular M. tuberculosis, allowing themselves and other antigens to gain access to the major histocompatibility complex class I processing pathway.