Expression and immunoactivity of chimeric particulate antigens of receptor binding site-core antigen of hepatitis B virus.
OBJECTIVE
To improve the immunogenicity of receptor binding site of hepatitis B virus (HBV) on preS1 antigen using HBV core antigen as an immuno-carrier.


METHODS
One to 6 tandem copies of HBV preS1 (21-47) fragment were inserted into HBcAg at the sites of aa 78 and 82, and expressed in E.coli. ELISA, Western blot and animal immunization were used to analyze the antigenicity and immmunogenicity of purified particulate antigens. The ability to capture HBV by antibodies elicited by chimeric particles was detected with immuno-capture PCR.


RESULTS
Recombinant antigens CI, CII, CIII carrying 1-3 copies of HBV preS1 (21-47) individually could form virus-like particles (VLPs), similar to HBcAg in morphology. But recombinant antigens carrying 4-6 copies of HBV preS1 (21-47) were poorly expressed in E.coli. Chimeric antigens were lacking of immunoreactivity with anti-HBc monoclonal antibodies (McAbs), but still reserved good immunoreactivity with anti-HBe McAbs. CI, CII, CIII could strongly react with anti-preS1 McAb, suggesting that preS1 (21-47) fragment was well exposed on the surface of chimeric VLPs. Three chimeric VLP antigens (CI, CII and CIII) could stimulate mice to produce high-level antibody responses, and their immunogenicity was stronger than non-particulate antigen 21-47*6, containing 6 copies of preS1 (21-47). Mouse antibodies to CI, CII and CIII were able to capture HBV virions in immuno-capture PCR assay in vitro.


CONCLUSIONS
Chimeric particulate antigens of receptor binding site-core antigen of HBV can elicit strong antibody responses to preS1. They have a potential to be developed into prophylactic or therapeutic vaccines against HBV infection.
Yang
Hai-Jie
HJ
The Key Laboratory of Ministry of Education for Cell Biology and Tumor Cell Engineering, Xiamen University, Xiamen 361005, Fujian Province, China.
Chen
Min
M
Cheng
Tong
T
He
Shui-Zhen
SZ
Li
Shao-Wei
SW
Guan
Bao-Quan
BQ
Zhu
Zi-Heng
ZH
Gu
Ying
Y
Zhang
Jun
J
Xia
Ning-Shao
NS
D000818:Animals; D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D001665:Binding Sites / Q000276:immunology; D015153:Blotting, Western; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005260:Female; D015967:Gene Expression Regulation, Viral; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control*; D006512:Hepatitis B Core Antigens / Q000276:immunology; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000235:genetics / Q000276:immunology*; D006513:Hepatitis B e Antigens / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D011498:Protein Precursors / Q000235:genetics* / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D014771:Virion / Q000276:immunology
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000939:Epitopes; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D006513:Hepatitis B e Antigens; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; C050806:presurface protein 1, hepatitis B surface antigen