DISCRETE CHARACTERISTICS OF ANTIBODIES RAISED AGAINST THYROTROPIN RECEPTOR-RELATED PEPTIDES WHOSE SEQUENCES ARE NOT CONSERVED IN THE LUTEINIZING-HORMONE CHORIONIC-GONADOTROPIN RECEPTOR
M. Murakami et al., DISCRETE CHARACTERISTICS OF ANTIBODIES RAISED AGAINST THYROTROPIN RECEPTOR-RELATED PEPTIDES WHOSE SEQUENCES ARE NOT CONSERVED IN THE LUTEINIZING-HORMONE CHORIONIC-GONADOTROPIN RECEPTOR, The Journal of clinical endocrinology and metabolism, 81(5), 1996, pp. 1747-1752
In order to identify the specific regions in the human TSH receptor fo
r TSAb and thyroid stimulation-blocking antibody (TSBAb), we produced
rabbit antibodies raised against several peptides of the extracellular
domain of the human TSH receptor, where sequences are not conserved i
n the LH/CG receptor, and measured the TSAb activity and TSBAb activit
y of those antibodies using Chinese hamster ovary cells expressing hum
an TSH receptors. Only antisera from rabbits that were immunized with
a peptide of amino acid 32-56, including the small insertion near the
N-terminal end of the extracellular domain, showed apparent TSAb activ
ities and have been shown to be significantly precipitated by IgG of p
atients with Graves' disease. TSAb, activity positively correlated wit
h the antibody titers against the peptide in those rabbits. In contras
t, antisera from rabbits immunized with a peptide of amino acid 352-37
8, including a part of the large insertion near the C-terminal end of
the extracellular domain, showed the obvious TSBAb activities. TSBAb a
ctivity also positively correlated with the degree of antibody titers
against the peptide in those rabbits. Moreover, this peptide was signi
ficantly immunoprecipitated by the IgG from hypothyroid patients who h
ad TSBAb, and the immunoprecipitation of this peptide positively corre
lated with TSBAb activities. These results suggest that the epitope re
sponsible for TSAb is quite different from that for TSBAb in the extra
cellular domain of the human TSH receptor.