T-cell recognition of mycobacterial antigens

T-cells play a dominant role in the immune response to mycobacterial infections. Most recognized mycobacterial antigens have been identified by monoclonal antibody techniques and, subsequently, sequenced and isolated by molecular cloning. Both CD4+ and CD8+ alpha beta T-cells, as well as gamma delta T-cells have been shown to participate in anti-mycobacterial host responses. The antigens recognized by CD4+ T-cells have been studied in most detail, with particular interest on proteins actively secreted by tubercle bacilli, on lipoproteins and on heat shock or stress proteins. Peptide mapping of T-cell epitopes of several mycobacterial proteins has suggested that many of their epitopes are recognized permissively in the context of multiple human and mouse major histocompatibility complex (MHC) class II alleles. This finding is encouraging for the development of subunit vaccines and diagnostic reagents.