title: CD1b restricts the response of human CD4-8- T lymphocytes to a microbial antigen.
abstract: Molecules encoded by the human CD1 locus on chromosome 1 (ref. 33) are recognized by selected CD4-8- T-cell clones expressing either alpha beta or gamma delta T-cell antigen receptors. The known structural resemblance of CD1 molecules to antigen-presenting molecules encoded by major histocompatibility complex (MHC) genes on human chromosome 6 (refs 3, 4, 34, 35), suggested that CD1 may represent a family of antigen-presenting molecules separate from those encoded in the MHC. Here we report that the proliferative and cytotoxic responses of human CD4-8- alpha beta TCR+ T cells specific for Mycobacterium tuberculosis can be restricted by CD1b, one of the four identified protein products of the CD1 locus. The responses of these T cells to M. tuberculosis seemed not to involve MHC encoded molecules, but were absolutely dependent on the expression of CD1b by the antigen-presenting cell and involved an antigen processing requirement similar to that seen in MHC class II-restricted antigen presentation. These results provide, to our knowledge, the first direct evidence for the proposed antigen-presenting function of CD1 molecules and suggest that the CD1 family plays a role in cell-mediated immunity to microbial pathogens.
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology*; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology*; D018949:Antigens, CD1; D001402:B-Lymphocytes / Q000276:immunology; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D002738:Chloroquine; D005404:Fixatives; D005976:Glutaral / Q000494:pharmacology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D015847:Interleukin-4 / Q000494:pharmacology; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D014162:Transfection
chemical_list: D000942:Antigens, Bacterial; D015703:Antigens, CD; D018949:Antigens, CD1; D015704:CD4 Antigens; D016827:CD8 Antigens; D005404:Fixatives; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D002738:Chloroquine; D005976:Glutaral