Thyroid-stimulating antibodies in sera from XXXX with @entity2743 are heterogeneous in epitope recognition.

@entity1 @entity2743 @entity535 @entity2621 @entity5010
Two synthetic peptides, P354-14 ( @entity535 nos. 354 to 367) and P338-16 (nos. 338 to 353), corresponding to the partial @entity535 sequences of the hTSH receptor structure were studied for their ability to bind specifically serum IgGs from @entity1 with @entity2743 and to inhibit thyroid stimulating TSH receptor antibody ( @entity5010 SAb) activity. IgG binding was measured by an ELISA using sera from 102 Graves', 20 @entity2621 @entity1 , and 9 normal subjects. Both peptides showed significantly increased IgG binding of Graves' sera compared with those of @entity2621 and normal sera. There was a significant correlation (r = 0.529) between the amount of IgG bound by the two peptides, but neither of these values correlated well with their @entity5010 SAb activity nor thyrotropin-binding inhibitor TSH receptor antibody ( @entity5010 IAb) activity. @entity5010 SAb inhibiting effects of these peptides were then analysed by measuring @entity5010 SAb activity after incubation with the peptides. Among eight Graves' IgGs tested the @entity5010 SAb activity of three was inhibited by both peptides, two were inhibited only by P354-14 and three were not affected by either. These @entity5010 SAb inhibiting effects were dose-dependent and reproducible. To confirm these findings, a peptide-sepharose gel affinity absorption study was performed. Eleven Graves' IgGs were applied to both peptide gels and the @entity5010 SAb activity of the unabsorbed fraction was measured. The @entity5010 SAb activity of five IgGs was strongly absorbed only by P354-14 and five others were absorbed by both peptides to an almost similar extent.(ABSTRACT TRUNCATED AT 250 WORDS)
