title: Pre-clinical evaluation of a novel nanoemulsion-based hepatitis B mucosal vaccine.
abstract: BACKGROUND
  Hepatitis B virus infection remains an important global health concern despite the availability of safe and effective prophylactic vaccines. Limitations to these vaccines include requirement for refrigeration and three immunizations thereby restricting use in the developing world. A new nasal hepatitis B vaccine composed of recombinant hepatitis B surface antigen (HBsAg) in a novel nanoemulsion (NE) adjuvant (HBsAg-NE) could be effective with fewer administrations.
  
  
  RESULTS
  Physical characterization indicated that HBsAg-NE consists of uniform lipid droplets (349+/-17 nm) associated with HBsAg through electrostatic and hydrophobic interactions. Immunogenicity of HBsAg-NE vaccine was evaluated in mice, rats and guinea pigs. Animals immunized intranasally developed robust and sustained systemic IgG, mucosal IgA and strong antigen-specific cellular immune responses. Serum IgG reached > or = 10(6) titers and was comparable to intramuscular vaccination with alum-adjuvanted vaccine (HBsAg-Alu). Normalization showed that HBsAg-NE vaccination correlates with a protective immunity equivalent or greater than 1000 IU/ml. Th1 polarized immune response was indicated by IFN-gamma and TNF-alpha cytokine production and elevated levels of IgG(2) subclass of HBsAg-specific antibodies. The vaccine retains full immunogenicity for a year at 4 degrees C, 6 months at 25 degrees C and 6 weeks at 40 degrees C. Comprehensive pre-clinical toxicology evaluation demonstrated that HBsAg-NE vaccine is safe and well tolerated in multiple animal models.
  
  
  CONCLUSIONS
  Our results suggest that needle-free nasal immunization with HBsAg-NE could be a safe and effective hepatitis B vaccine, or provide an alternative booster administration for the parenteral hepatitis B vaccines. This vaccine induces a Th1 associated cellular immunity and also may provide therapeutic benefit to patients with chronic hepatitis B infection who lack cellular immune responses to adequately control viral replication. Long-term stability of this vaccine formulation at elevated temperatures suggests a direct advantage in the field, since potential excursions from cold chain maintenance could be tolerated without a loss in therapeutic efficacy.
authors.affiliation: Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, Michigan, United States of America.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Makidon
authors.forename: Anna U
authors.initials: AU
authors.lastname: Bielinska
authors.forename: Shraddha S
authors.initials: SS
authors.lastname: Nigavekar
authors.forename: Katarzyna W
authors.initials: KW
authors.lastname: Janczak
authors.forename: Jessica
authors.initials: J
authors.lastname: Knowlton
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Scott
authors.forename: Nicholas
authors.initials: N
authors.lastname: Mank
authors.forename: Zhengyi
authors.initials: Z
authors.lastname: Cao
authors.forename: Sivaprakash
authors.initials: S
authors.lastname: Rathinavelu
authors.forename: Michael R
authors.initials: MR
authors.lastname: Beer
authors.forename: J Erby
authors.initials: JE
authors.lastname: Wilkinson
authors.forename: Luz P
authors.initials: LP
authors.lastname: Blanco
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Landers
authors.forename: James R
authors.initials: JR
authors.lastname: Baker
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D000917:Antibody Formation; D002626:Chemistry, Pharmaceutical; D004304:Dosage Forms; D004655:Emulsions; D006514:Hepatitis B Surface Antigens / Q000008:administration & dosage* / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D010316:Particle Size; D011994:Recombinant Proteins / Q000008:administration & dosage; D019444:Vaccines, DNA / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D004304:Dosage Forms; D004655:Emulsions; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D019444:Vaccines, DNA