Scientific Publications by FDA Staff

Proc Natl Acad Sci U S A 2013 Apr 30;110(18):7418-22

Structural evidence for a bifurcated mode of action in the antibody-mediated neutralization of hepatitis C virus.

Deng L, Zhong L, Struble E, Duan H, Ma L, Harman C, Yan H, Virata-Theimer ML, Zhao Z, Feinstone S, Alter H, Zhang P

Hepatitis C virus (HCV) envelope glycoprotein E2 has been considered as a major target for vaccine design. Epitope II, mapped between residues 427-446 within the E2 protein, elicits antibodies that are either neutralizing or nonneutralizing. The fundamental mechanism of antibody-mediated neutralization at epitope II remains to be defined at the atomic level. Here we report the crystal structure of the epitope II peptide in complex with a monoclonal antibody (mAb#8) capable of neutralizing HCV. The complex structure revealed that this neutralizing antibody engages epitope II via interactions with both the C-terminal a-helix and the N-terminal loop using a bifurcated mode of action. Our structural insights into the key determinants for the antibody-mediated neutralization may contribute to the immune prophylaxis of HCV infection and the development of an effective HCV vaccine.