We have established anti-colon antibodies producing B cell clones from the patient with ulcerative colitis, and analyzed the immunoglobulin heavy chain variable region (VH) gene segments of these clones using RT-PCR with VH family specific primers. VH3 family was used by all ten clones from ulcerative colitis that produced anti-colon antibodies, while various VH gene families were used by eight clones from normal controls. By nucleotide sequence analysis, two LPL clones were thought to be derived from a germ line gene segment, VH26. However, other three PBL clones were derived from 22-2B, 9-1 and 1.9-III, respectively. These results suggest the heterogeneity of the colonic antigens that autoantibodies in ulcerative colitis recognize.