Transgenic mice expressing HLA-DQA1*0301 and HLA-DQB1*0302 genes (DQ8) were produced. The transgenes were then transferred into mouse (Ab degrees) class II negative mice: the only class II molecules expressed in these animals were therefore coded by the HLA-DQ8 genes. Good expression of HLA-DQ molecules was found. Both CD4+ T cells and DQ8-specific T-cell receptor V beta expressing cells were positively selected in these mice. The HLA-DQ8 molecules expressed in these animals can present various foreign and self antigens and induce T-cell proliferation in vitro. These mice will be invaluable in future studies of the structure and function of HLA-DQ8 genes.