Genetic Removal of the CH1 Exon Enables the Production of Heavy Chain-Only IgG in Mice

Front Immunol. 2018 Sep 25:9:2202. doi: 10.3389/fimmu.2018.02202. eCollection 2018.

Abstract

Nano-antibodies possess great potential in many applications. However, they are naturally derived from heavy chain-only antibodies (HcAbs), which lack light chains and the CH1 domain, and are only found in camelids and sharks. In this study, we investigated whether the precise genetic removal of the CH1 exon of the γ1 gene enabled the production of a functional heavy chain-only IgG1 in mice. IgG1 heavy chain dimers lacking associated light chains were detected in the sera of the genetically modified mice. However, the genetic modification led to decreased expression of IgG1 but increased expression of other IgG subclasses. The genetically modified mice showed a weaker immune response to specific antigens compared with wild type mice. Using a phage-display approach, antigen-specific, single domain VH antibodies could be screened from the mice but exhibited much weaker antigen binding affinity than the conventional monoclonal antibodies. Although the strategy was only partially successful, this study confirms the feasibility of producing desirable nano-bodies with appropriate genetic modifications in mice.

Keywords: CH1 domain; HcAbs; mouse; nanobody; phage display; single domain antibodies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / genetics
  • Antibodies, Monoclonal / immunology*
  • Exons / genetics
  • Exons / immunology
  • Feasibility Studies
  • Immunoglobulin Constant Regions / genetics
  • Immunoglobulin Constant Regions / immunology
  • Immunoglobulin gamma-Chains / genetics
  • Immunoglobulin gamma-Chains / immunology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Peptide Library
  • Protein Domains / genetics
  • Protein Domains / immunology
  • Protein Engineering*
  • Single-Domain Antibodies / genetics
  • Single-Domain Antibodies / immunology*

Substances

  • Antibodies, Monoclonal
  • Immunoglobulin Constant Regions
  • Immunoglobulin gamma-Chains
  • Peptide Library
  • Single-Domain Antibodies