Regulation of T cell responsiveness against mycobacterial antigens by HLA class 2 immune response genes.

Helper T lymphocytes can only recognize mycobacterial antigens when they are presented by HLA class 2 molecules. Thus, these molecules may play an important role in the regulation of the immune response against mycobacteria. In this paper it is demonstrated that the T cells from individuals with different HLA class 2 molecules react to different mycobacterial antigens. These data indicate that HLA class 2 molecules are the products of immune response (Ir) genes for mycobacteria. Such genetically controlled differences in antimycobacterial T cell reactivity may explain the association of certain HLA class 2 alleles with a different course of mycobacterial infections and may have implications for vaccine development.