Pre-clinical evaluation of a novel nanoemulsion-based hepatitis B mucosal vaccine.
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.
Makidon
Paul E
PE
Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, Michigan, United States of America.
Bielinska
Anna U
AU
Nigavekar
Shraddha S
SS
Janczak
Katarzyna W
KW
Knowlton
Jessica
J
Scott
Alison J
AJ
Mank
Nicholas
N
Cao
Zhengyi
Z
Rathinavelu
Sivaprakash
S
Beer
Michael R
MR
Wilkinson
J Erby
JE
Blanco
Luz P
LP
Landers
Jeffrey J
JJ
Baker
James R
JR
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
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