Single domain antibody multimers confer protection against rabies infection

PLoS One. 2013 Aug 20;8(8):e71383. doi: 10.1371/journal.pone.0071383. eCollection 2013.

Abstract

Post-exposure prophylactic (PEP) neutralizing antibodies against Rabies are the most effective way to prevent infection-related fatality. The outer envelope glycoprotein of the Rabies virus (RABV) is the most significant surface antigen for generating virus-neutralizing antibodies. The small size and uncompromised functional specificity of single domain antibodies (sdAbs) can be exploited in the fields of experimental therapeutic applications for infectious diseases through formatting flexibilities to increase their avidity towards target antigens. In this study, we used phage display technique to select and identify sdAbs that were specific for the RABV glycoprotein from a naïve llama-derived antibody library. To increase their neutralizing potencies, the sdAbs were fused with a coiled-coil peptide derived from the human cartilage oligomeric matrix protein (COMP48) to form homogenous pentavalent multimers, known as combodies. Compared to monovalent sdAbs, the combodies, namely 26424 and 26434, exhibited high avidity and were able to neutralize 85-fold higher input of RABV (CVS-11 strain) pseudotypes in vitro, as a result of multimerization, while retaining their specificities for target antigen. 26424 and 26434 were capable of neutralizing CVS-11 pseudotypes in vitro by 90-95% as compared to human rabies immunoglobulin (HRIG), currently used for PEP in Rabies. The multimeric sdAbs were also demonstrated to be partially protective for mice that were infected with lethal doses of rabies virus in vivo. The results demonstrate that the combodies could be valuable tools in understanding viral mechanisms, diagnosis and possible anti-viral candidate for RABV infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Neutralizing / classification
  • Antibodies, Neutralizing / genetics
  • Antibodies, Neutralizing / immunology*
  • Antibodies, Viral / classification
  • Antibodies, Viral / genetics
  • Antibodies, Viral / immunology*
  • Camelids, New World
  • Cartilage Oligomeric Matrix Protein / genetics
  • Cartilage Oligomeric Matrix Protein / immunology
  • Escherichia coli / genetics
  • Humans
  • Mice
  • Peptide Library
  • Phylogeny
  • Protein Multimerization
  • Rabies / immunology
  • Rabies / prevention & control*
  • Rabies Vaccines / administration & dosage
  • Rabies Vaccines / genetics
  • Rabies Vaccines / immunology*
  • Rabies virus / genetics
  • Rabies virus / immunology*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology
  • Single-Domain Antibodies / classification
  • Single-Domain Antibodies / genetics
  • Single-Domain Antibodies / immunology*
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / immunology*

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • COMP protein, human
  • Cartilage Oligomeric Matrix Protein
  • Peptide Library
  • Rabies Vaccines
  • Recombinant Fusion Proteins
  • Single-Domain Antibodies
  • Viral Envelope Proteins

Grants and funding

This work was supported by grants from the Ministry of Science and Technology of China (S & T Major Program: No. 2012ZX10004701-001-002, 2009ZX10004103-002, 2008ZX10003012-002-008, 2009ZX10004101-003-002, 2009ZX09503-007, 2009ZX10004-305) and the National Natural Science Foundation of China (No. 30771953, 31070783, 81021003). The funding agencies had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.