Construction of single-chain Fv with two possible CDR3H conformations but similar inter-molecular forces that neutralize bovine herpesvirus 1

Mol Immunol. 2010 Feb;47(5):953-60. doi: 10.1016/j.molimm.2009.11.011. Epub 2009 Dec 16.


Bovine herpesvirus 1 (BoHV-1) causes respiratory and genital diseases in cattle for which available vaccines do not confer adequate protection. Since passive immunization with antibodies permits disease prevention, single-chain fragment variable (scFv), originating from a monoclonal bovine IgG1 antibody against BoHV-1, were constructed and expressed in Pichia pastoris in V(lambda)-V(H) orientation via a flexible seven-amino acid linker. Similar to the intact IgG, the purified recombinant scFv neutralized BoHV-1 in vitro and recognized viral antigens in BoHV-1 infected MDBK cells by immunofluorescence. Homology modeling of the Fv predicts two distinct conformations for CDR3H. Firstly, a long protruding CDR3H conformation where no disulfide linkage occurred between two "non-canonical" Cys residues resulted in a large binding cavity between V(lambda) and V(H). Secondly, a smaller potential antigen-binding cavity is predicted with a disulfide linkage between the two Cys residues of CDR3H creating a six-membered loop in the ascending polypeptide, which fitted into the space between V(lambda) and V(H). Despite such potential configurational diversity of the antigen-binding site, the electrostatic surface potentials that would interact with the BoHV-1 epitope are largely similar for both the topographies where salt-bridge type electrostatic interactions likely occur at the edges of the binding site. Given that IgG1 antibody against BoHV-1 is clonally selected, it is likely that disulfide-stabilized broader and flatter surface topography is specifically generated to accommodate the predicted carbohydrate neutralizing B-epitope on BoHV-1. The specificity and neutralizing capacity for BoHV-1 of the scFv should make this bovine antibody fragment a useful diagnostic and potential therapeutic candidate for an important viral pathogen in cattle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / genetics
  • Antibodies, Monoclonal / immunology*
  • Antibodies, Monoclonal / pharmacology
  • Antibodies, Neutralizing / genetics
  • Antibodies, Neutralizing / immunology*
  • Antibodies, Neutralizing / pharmacology
  • Antibodies, Viral / genetics
  • Antibodies, Viral / immunology*
  • Antibodies, Viral / pharmacology
  • Antibody Specificity / genetics
  • Antibody Specificity / immunology*
  • Binding Sites, Antibody / genetics
  • Binding Sites, Antibody / immunology
  • Cattle
  • Cell Line
  • Complementarity Determining Regions / genetics
  • Complementarity Determining Regions / immunology*
  • Complementarity Determining Regions / pharmacology
  • Herpesvirus 1, Bovine / immunology*
  • Immunoglobulin G / genetics
  • Immunoglobulin G / immunology*
  • Immunoglobulin G / pharmacology
  • Infectious Bovine Rhinotracheitis / immunology*
  • Infectious Bovine Rhinotracheitis / prevention & control
  • Mice
  • Protein Structure, Secondary / genetics
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Recombinant Proteins / pharmacology


  • Antibodies, Monoclonal
  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Complementarity Determining Regions
  • Immunoglobulin G
  • Recombinant Proteins