Human combinatorial libraries yield rare antibodies that broadly neutralize hepatitis C virus
Published online before print October 2, 2007
Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0705522104
Daniel X. Johansson *, Cécile Voisset {dagger}, Alexander W. Tarr {ddagger}, Mie Aung {ddagger}, Jonathan K. Ball {ddagger}, Jean Dubuisson {dagger}, and Mats A. A. Persson *{sect}
*Department of Medicine, Center for Molecular Medicine, Karolinska University Hospital Solna, Karolinska Institutet, 171 76 Stockholm, Sweden; {dagger}Institut de Biologie de Lille, Unité Mixte de Recherche 8161, Centre National de la Recherche Scientifique, Université de Lille I and II and Institut Pasteur de Lille, 59045 Lille, France; and {ddagger}Institute of Infection, Immunity, and Inflammation, School of Molecular Medical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom
Communicated by Richard A. Lerner, The Scripps Research Institute, La Jolla, CA, July 27, 2007 (received for review May 29, 2007)
One way to dissect the antibody response to an invading microorganism is to clone the antibody repertoire from immune donors and subsequently characterize the specific antibodies. Recently, methodological advances have allowed investigations of neutralizing antibodies against hepatitis C virus (HCV) in vitro. We have investigated three human mAbs, previously isolated from an individual infected with HCV of genotype 2b, that are known to cross-react in a binding assay to the envelope E2 protein of genotypes 1a and 1b. We now report that two of them have a neutralizing activity with a breadth not previously observed. Indeed, mAbs 1:7 and A8 recognized E2 from all of the six major genotypes, and they neutralized retroviral pseudoparticles [HCV pseudoparticles (HCVpp)] carrying genetically equally diverse HCV envelope glycoproteins. Importantly, these antibodies were also able to neutralize the cell culture infectious HCV clone JFH-1 in vitro, with IC50 values of 60 ng/ml and 560 ng/ml, respectively. The conformational epitopes of these two broadly reactive antibodies were overlapping yet distinct and involved amino acid residues in the 523–535 region of E2, known to be important for the E2–CD81 interaction. The third antibody clone, representing a dominant population in the initial screen for these antibodies, was less broadly reactive and was unable to neutralize the genotype 2a infectious clone JFH-1. Our results confirm at the clonal level that broadly neutralizing human anti-HCV antibodies can be elicited and that the region amino acids 523–535 of the HCV envelope glycoprotein E2 carries neutralizing epitopes conserved across all genotypes.
Author contributions: D.X.J., J.D., and M.A.A.P. designed research; D.X.J., C.V., A.W.T., and M.A. performed research; C.V., A.W.T., J.K.B., J.D., and M.A.A.P. contributed new reagents/analytic tools; D.X.J., C.V., A.W.T., M.A., J.K.B., J.D., and M.A.A.P. analyzed data; and D.X.J., C.V., A.W.T., J.K.B., J.D., and M.A.A.P. wrote the paper.
Conflict of interest statement: The antibodies analyzed in this article have been the topic of a patent application since 1996. It is currently assigned to Karolinska Innovations AB, a tech transfer office of the Karolinska Institutet, where M.A.A.P. performed the work. However, the patent and patent applications are in the process of being transferred to a spinoff company, Molecules of Man AB. M.A.A.P. has a financial interest in this company (as shareholder).
{sect}To whom correspondence should be addressed.
Mats A. A. Persson, E-mail: mats.persson@ki.se
www.pnas.org/cgi/doi/10.1073/pnas.0705522104 |
