Construction and characterization of an experimental ISCOMS-based hepatitis B polypeptide vaccine.
OBJECTIVE
To characterize the biochemical and immunological properties of an experimental ISCOMS vaccine prepared from a novel therapeutic polypeptide based on T cell epitopes of HBsAg, and a heptatis B-ISCOMS was prepared and investigated.


METHODS
An immunostimulating complexes(ISCOMS)-based vaccine containing a novel therapeutic hepatitis B polypeptide was prepared by dialysis method, and its formation was visualized by electron microscopy and biochemically verified by SDS-polyacrylamide gel electrophoresis. Amount of the peptide within ISCOMS was determined by Bradford assay, and specific CTL response was detected by ELISPOT assay.


RESULTS
Typical cage-like structures of submicroparticle with a diameter of about 40nm were observed by electron microscopy. Results from Bradford assay showed that the level of peptide incorporation was about 0.33g.L(-1). At the paralleled position close to the sixth band of the molecular weight marker(3480kDa) a clear band was shown in SDS-PAGE analysis, indicating successful incorporation of polypeptide into ISCOMS. It is suggested that ISCOMS delivery system could efficiently improve the immunogenicity of polypeptide and elicit specific immune responses in vivo by the results of ELISPOT assay, which showed that IFN-gamma producing cells(specific CTL responses) were increased(spots of ISCOMS-treated group: 47+/-5, n =3; control group: 5+/-2, n =3).


CONCLUSIONS
ISCOMS-based hepatitis B polypeptide vaccine is successfully constructed and it induces a higher CTL response compared with short polypeptides vaccine in vivo.
Guan
Xiao-Ju
XJ
Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200031, China.
Guan
Xiao-Jun
XJ
Wu
Yu-Zhang
YZ
Jia
Zheng-Cai
ZC
Shi
Tong-Dong
TD
Tang
Yan
Y
D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D005260:Female; D006514:Hepatitis B Surface Antigens / Q000276:immunology; D017325:Hepatitis B Vaccines / Q000276:immunology; D006801:Humans; D016882:ISCOMs; D007371:Interferon-gamma / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D000939:Epitopes; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D016882:ISCOMs; D010455:Peptides; D007371:Interferon-gamma