Fig 2: (A) Profiles of hTSHR-169 fusion protein induced by 0.1 mM IPTG. Samples were separated in 12% SDS-PAGE gel. Protein bands were visualized by coomassie brilliant blue staining. M: protein marker; NI: without IPTG; I: with IPTG. (B) Western blot experiments to examine the purified hTSHR-169 fusion protein's antigenicity. A single band at the expected size of 16.8 kDa was detected when purified fractions of hTSHR-169 were incubated with monoclonal anti-TSHR antibody and serum collected from GD patients, but not in healthy control. M: protein marker. (C) Optimization of dot blot assay, recombinant hTSHR-169 was spotted onto the NCM (different concentrations from 10–1000 ng) and incubated with serum collected from GD patient or healthy subject (twofold dilution ranging from 1:20 to 1:120). Ag (-) or Ab (-) indicate that NCM was probed only with recombinant TSHR-169 or TRAb, respectively. Arrow indicates the minimum concentration required to detect TRAb in GD samples compare to control