Abstract: Objective To detect the B cell epitopes of human MCHR1 recognized by serum autoantibodies in patients with vitiligo. Methods The DNA encoding antigen fragments of MCHR1 from amino acid (aa) 1 to 94 were amplified from pcDNA3/MCHR1 by PCR and inserted into the vector pGEX-4T-1. After identification, the recombinant plasmid pGEX-4T-1/MCHR1 was transfected into E. coli for fusion protein production which was purified by GST agarose affinity chromatography later. The sera from 38 vitiligo patients were examined for MCHR1 antibodies by enzyme-linked immunoabsorbent assay. Results Amino acids (aa) 1 to 94 of MCHR1 which most possibly included in B cell epitopes were selected to express. The recombinant plasmid pGEX-4T/MCHR1 was confirmed by sequence analysis. SDS-PAGE showed that a Mr 37 kD fusion protein was expressed by E.coli. Of the sera from vitiligo patients examined by ELISA, 5 of 38 were considered positive for MCHR1 antibody. Conclusion There are B cell epitopes in amino acids(aa) 1 to 94 of MCHR1 which can be recognized by antibodies from vitiligo patients.

Key words: Vitiligo, Melanocytes, Epitopes