Abstract: Bullous pemphigoid has two autoantigens:BPAG1 (220 000～240 000) and BPAG2 (160 000～180 000),which are distinct gene products.In this paper we constructed a cDNA clone encoding BPAG2 fragment by PCR to study the molecular characters of BPAG2.First we synthesized specific primers,and a Hind Ⅲ restriction enzyme site was added to the downstream primer.Then a 588bp at BPAG2 amino terminal was amplified from human keratinoeyte cDNA library.This PCR products were cloned into a plasmid pKPL-3a digested with Nco Ⅰ and Hind Ⅲ and then transformed E.coli. pop2136.We screened out a positive recombinant clone,and confirmed that the insert in this recombi-nant encoded the amino-terminal non-collagenous domain of BPAG2 by restriction enzymes digestion and DNA sequencing.

Key words: Pemphigoid,bullous, Antigens, cDNA