1. ¹Department of Microbiology, Second Military Medical University, Shanghai 200433, China E-mail: qizt@smmu.edu.cn
2. ²Department of Infectious Diseases, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China

Correspondence: Zhong Tian QI, Department of Microbiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China. Tel/fax: 0086-21-25070312; E-mail: qizt@smmu.edu.cn

Received 21 January 2003; Revised 10 August 2003; Accepted 15 September 2003.

Abstract

The human CD81 (hCD81), the most recently proposed receptor of hepatitis C virus (HCV), can especifically bind to HCV envelope glycoprotein 2 (E2). In this study, hCD81-expressing murine NIH/3T3 cells were used to select hCD81-binding peptides from a phage displayed nonapeptide library (PVIII9aaCys). Eighteen of the 75 clones selected from the library showed specific binding to the hCD81-expressing NIH/3T3 cells by enzyme linked immunosorbent assay (ELISA) and competitive inhibition test. Twelve out of the 18 clones shared the amino acid motif SPQYWTGPA. Sequence comparison of the motif showed no amino acid homology with the native HCV E2. The motif-containing phages could competitively inhibit the ability of HCV E2 binding to native hCD81-expressing MOLT-4 cells, and induce HCV E2 specific immune response in vivo. These results suggest that the selected motif SPQYWTGPA should be a mimotope of HCV E2 to bind to hCD81 molecules. Our findings cast new light on developing HCV receptor antagonists.