ICAM-1-based rabies virus vaccine shows increased infection and activation of primary murine B cells in vitro and enhanced antibody titers in-vivo

PLoS One. 2014 Jan 29;9(1):e87098. doi: 10.1371/journal.pone.0087098. eCollection 2014.

Abstract

We have previously shown that live-attenuated rabies virus (RABV)-based vaccines infect and directly activate murine and human primary B cells in-vitro, which we propose can be exploited to help develop a single-dose RABV-based vaccine. Here we report on a novel approach to utilize the binding of Intracellular Adhesion Molecule-1 (ICAM-1) to its binding partner, Lymphocyte Function-associated Antigen-1 (LFA-1), on B cells to enhance B cell activation and RABV-specific antibody responses. We used a reverse genetics approach to clone, recover, and characterize a live-attenuated recombinant RABV-based vaccine expressing the murine Icam1 gene (rRABV-mICAM-1). We show that the murine ICAM-1 gene product is incorporated into virus particles, potentially exposing ICAM-1 to extracellular binding partners. While rRABV-mICAM-1 showed 10-100-fold decrease in viral titers on baby hamster kidney cells compared to the parental virus (rRABV), rRABV-mICAM-1 infected and activated primary murine B cells in-vitro more efficiently than rRABV, as indicated by significant upregulation of CD69, CD40, and MHCII on the surface of infected B cells. ICAM-1 expression on the virus surface was responsible for enhanced B cell infection since pre-treating rRABV-mICAM-1 with a neutralizing anti-ICAM-1 antibody reduced B cell infection to levels observed with rRABV alone. Furthermore, 100-fold less rRABV-mICAM-1 was needed to induce antibody titers in immunized mice equivalent to antibody titers observed in rRABV-immunized mice. Of note, only 10(3) focus forming units (ffu)/mouse of rRABV-mICAM-1 was needed to induce significant anti-RABV antibody titers as early as five days post-immunization. As both speed and potency of antibody responses are important in controlling human RABV infection in a post-exposure setting, these data show that expression of Icam1 from the RABV genome, which is then incorporated into the virus particle, is a promising strategy for the development of a single-dose RABV vaccine that requires only a minimum of virus.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Viral / biosynthesis*
  • B-Lymphocytes / immunology
  • B-Lymphocytes / virology
  • Cell Line
  • Cricetinae
  • Female
  • Gene Expression
  • Genome, Viral*
  • Humans
  • Immunity, Humoral / drug effects
  • Intercellular Adhesion Molecule-1 / genetics
  • Intercellular Adhesion Molecule-1 / immunology*
  • Lymphocyte Function-Associated Antigen-1 / genetics
  • Lymphocyte Function-Associated Antigen-1 / immunology
  • Mice
  • Mice, Inbred C57BL
  • Rabies / immunology
  • Rabies / prevention & control*
  • Rabies / virology
  • Rabies Vaccines / administration & dosage
  • Rabies Vaccines / genetics
  • Rabies Vaccines / immunology*
  • Rabies virus / genetics
  • Rabies virus / immunology*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / immunology
  • Vaccines, Attenuated
  • Vaccines, Synthetic
  • Viral Proteins / genetics
  • Viral Proteins / immunology*
  • Virion / genetics
  • Virion / immunology

Substances

  • Antibodies, Viral
  • Lymphocyte Function-Associated Antigen-1
  • Rabies Vaccines
  • Recombinant Fusion Proteins
  • Vaccines, Attenuated
  • Vaccines, Synthetic
  • Viral Proteins
  • Intercellular Adhesion Molecule-1