title: Immune responses to HBsAg conjugated to protein D of non-typeable Haemophilus influenzae in mice.
abstract: BACKGROUND
  Hepatitis B vaccine that contains an aluminum hydroxide adjuvant induces apoptotic death of Hepa 1-6 cells. Difficult-to-degrade chemical additives in vaccines effectively enhance vaccine immunogenicity, but also affect the host tissue. Identification of bio-molecules that are readily degraded and compatible in vivo as an adjuvant is important for vaccine research. The hapten-carrier effect suggests that stimulation of helper T (Th) cells by carrier adjuvants is feasible. Protein D (PD) of non-typeable Haemophilus influenzae covalently conjugated to some polysaccharide vaccines has been confirmed to convert T-cell independent (TI) antigens into T-cell dependent (TD) antigens, and elicit strong T-cell responses ultimately. Herein, we would substitube PD for aluminum hydroxide adjuvant in Hepatitis B vaccine.
  
  
  RESULTS
  Truncated PD (amino acids 20-364) was expressed in Escherichia coli and purified by (NH4)2SO4 precipitation and DEAE chromatography. After evaluation of antigenicity by western blotting, PD was covalently conjugated to yeast-derived recombinant HBsAg by cross-linking with glutaraldehyde. Intramuscular immunization with the conjugate induced higher level of HBsAg-specific antibody than did HBsAg alone (p < 0.05), and was comparable to commercial Hepatitis B vaccine. During the surveillance period (days 35-105), anti-HBs titers were hold high. Moreover, the conjugated vaccine enhanced Th1 immune responses, while Th2 responses were also activated and induced an antibody response, as determined by IFN-γ ELISPOT and IgG1/IgG2a ratio assays.
  
  
  CONCLUSIONS
  Recombinant truncated PD covalently conjugated to HBsAg antigen enhanced the immunogenicity of the antigen in mice simultaneously by humoral and cellular immune response, which would facilitate therapeutic hepatitis B vaccines.
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Qiudong
authors.initials: Q
authors.lastname: Su
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Yi
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Qiu
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Xuexin
authors.initials: X
authors.lastname: Lu
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Junying
authors.initials: J
authors.lastname: Ding
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Jia
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Ruiguang
authors.initials: R
authors.lastname: Tian
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Beijing, China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Bi
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002450:Cell Communication / Q000276:immunology; D005260:Female; D006193:Haemophilus influenzae / Q000145:classification / Q000276:immunology*; D006514:Hepatitis B Surface Antigens / Q000276:immunology* / Q000378:metabolism; D018796:Immunoconjugates / Q000276:immunology*; D007072:Immunoglobulin D / Q000235:genetics / Q000378:metabolism*; D007074:Immunoglobulin G / Q000276:immunology; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D010957:Plasmids / Q000235:genetics; D013154:Spleen / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D001426:Bacterial Proteins; D002352:Carrier Proteins; D006514:Hepatitis B Surface Antigens; D018796:Immunoconjugates; D007072:Immunoglobulin D; D007074:Immunoglobulin G; D008074:Lipoproteins; D014765:Viral Vaccines; C067989:glpQ protein, Haemophilus influenzae