Enhanced binding of antibodies generated during chronic HIV infection to mucus component MUC16

Mucosal Immunol. 2016 Nov;9(6):1549-1558. doi: 10.1038/mi.2016.8. Epub 2016 Mar 9.

Abstract

Transmission of HIV across mucosal barriers accounts for the majority of HIV infections worldwide. Thus, efforts aimed at enhancing protective immunity at these sites are a top priority, including increasing virus-specific antibodies (Abs) and antiviral activity at mucosal sites. Mucin proteins, including the largest cell-associated mucin, mucin 16 (MUC16), help form mucus to provide a physical barrier to incoming pathogens. Here, we describe a natural interaction between Abs and MUC16 that is enhanced in specific disease settings such as chronic HIV infection. Binding to MUC16 was independent of IgG subclass, but strongly associated with shorter Ab glycan profiles, with agalactosylated (G0) Abs demonstrating the highest binding to MUC16. Binding of Abs to epithelial cells was diminished following MUC16 knockdown, and the MUC16 N-linked glycans were critical for binding. Further, agalactosylated VRC01 captured HIV more efficiently in MUC16. These data point to a novel opportunity to enrich Abs at mucosal sites by targeting Abs to MUC16 through changes in Fc glycosylation, potentially blocking viral movement and sequestering the virus far from the epithelial border. Thus, next-generation vaccines or monoclonal therapeutics may enhance protective immunity by tuning Ab glycosylation to promote the enrichment of Abs at mucosal barriers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibody Affinity / immunology
  • CA-125 Antigen / immunology*
  • CA-125 Antigen / metabolism
  • Female
  • Glycosylation
  • HIV Antibodies / immunology*
  • HIV Antibodies / metabolism
  • HIV Infections / immunology*
  • HIV Infections / metabolism
  • HIV Infections / virology*
  • HIV-1 / immunology*
  • Humans
  • Immunoglobulin Fc Fragments / immunology
  • Immunoglobulin Fc Fragments / metabolism
  • Immunoglobulin G / immunology
  • Membrane Proteins / immunology*
  • Membrane Proteins / metabolism
  • Mucous Membrane / immunology
  • Mucous Membrane / metabolism
  • Mucous Membrane / virology
  • Mucus / metabolism
  • Protein Binding
  • Vagina

Substances

  • CA-125 Antigen
  • HIV Antibodies
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G
  • MUC16 protein, human
  • Membrane Proteins