V-beta-8-positive T cells were isolated from human peripheral blood lymphocytes using a monoclonal antibody specific for the V beta 8 family. Alloreactive T-cell lines were generated by stimulation with mononuclear cells from individuals homozygous for HLA DR1-DR9. Cloned V beta 8-positive T cells were then assayed for alloreactivity based on a proliferative assay using irradiated B-cell lines. V beta 8-positive T-cell clones alloreactive to DR2 and DR5 molecules were chosen for further study based on the association of these MHC antigens with autoimmune disease. DNA sequence analysis confirmed the use of the V beta 8 gene family as well as providing information on the use of the V, D, J and N segments in these alloreactive T-cell clones.