title: High precursor frequency of human T cells reactive to HLA-DQ molecules expressed on mouse L cell transfectants.
abstract: In humans, the HLA-DR molecule is a major stimulatory molecule of allogeneic mixed lymphocyte reactions (MLR) and a major restriction molecule for the presentation of soluble antigens to the T cell. Little is known of the biological function of HLA-DQ. To examine the size of the repertoire of precursor T cells recognizing the autologous or allogeneic HLA-DQ molecule, the frequency of T cells reactive to HLA-DQ was estimated in comparison with T cells reactive to HLA-DR. We made use of a limiting dilution analysis and mouse L cells transfectants expressing the HLA-DR or -DQ molecule, as stimulators. Human T cells recovered from a primary MLR stimulated with allogeneic peripheral blood lymphocytes (PBL) proliferated in response to L cell transfectants expressing HLA class II genes shared by the stimulator cells in the primary MLR. This observation suggested that the HLA class II molecules on L cell transfectants shared to some extent epitopes for alloreactive T cells with those expressed on human PBL. The precursor frequencies of CD4+ T cells reactive to allogeneic or autologous DQ molecules were as high as those of T cells reactive to allogeneic DR molecules and were estimated to be 1/800-1/1800. The frequency of the T cells reactive to autologous DR molecules was low (1/7200-1/16,000). The biological significance of the high frequency of HLA-DQ-reactive precursor T cells is discussed.
authors.affiliation: Department of Genetics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fujisawa
authors.forename: N
authors.initials: N
authors.lastname: Kamikawaji
authors.forename: M
authors.initials: M
authors.lastname: Yasunami
authors.forename: A
authors.initials: A
authors.lastname: Kimura
authors.forename: Y
authors.initials: Y
authors.lastname: Nishimura
authors.forename: T
authors.initials: T
authors.lastname: Sasazuki
mesh_terms: D000818:Animals; D000939:Epitopes; D006683:HLA-DQ Antigens / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007739:L Cells; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D014162:Transfection
chemical_list: D000939:Epitopes; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens