ICAM-1-based rabies virus vaccine shows increased infection and activation of primary murine B cells in vitro and enhanced antibody titers in-vivo.
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.
Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
James E
JE
Norton
Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
Andrew G
AG
Lytle
Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
Shixue
S
Shen
Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
Evgeni P
EP
Tzvetkov
Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
Corin L
CL
Dorfmeier
Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America ; Jefferson Vaccine Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America.
James P
JP
McGettigan
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000276:immunology / Q000821:virology; D002460:Cell Line; D006224:Cricetinae; D005260:Female; D015870:Gene Expression; D016679:Genome, Viral; D006801:Humans; D056724:Immunity, Humoral / Q000187:drug effects; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000276:immunology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D011818:Rabies / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D011819:Rabies Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011820:Rabies virus / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology*; D014771:Virion / Q000235:genetics / Q000276:immunology
D000914:Antibodies, Viral; D016169:Lymphocyte Function-Associated Antigen-1; D011819:Rabies Vaccines; D011993:Recombinant Fusion Proteins; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014764:Viral Proteins; D018799:Intercellular Adhesion Molecule-1