[Variable-regions of immunoglobulin H-chain genes encoding anti-TSH receptor antibodies].

We have established EBV-transformed human B cell clones producing monoclonal anti-TSH receptor antibodies from two patients with Graves' disease. We then isolated and characterized immunoglobulin VH genes of 5 B cell clones with the TBII activity and 4 B cell clones with the TSAb activity. We found that VH gene families used in the 5 TBII clones were all VH-III, while those of the 4 TSAb clones were diverse, including VH-II, -III, -IV and -V. Most of VH segments used in TBII and TSAb are commonly used in other autoantibodies and fetal liver repertoire. The frequency of somatic mutations in TBII was higher than that in TSAb. Since the same germline VH segment (V3-23) was used for both TBII and TSAb, the frequency and position of somatic mutations may be important for generation of TBII and TSAb.