[The fusion protein of cytoplasmic transduction peptide (CTP)-HBcAg18-27-Tapasin enhances specific immune response to hepatitis B virus and inhibits viral replication in transgenic mice].
OBJECTIVE
To investigate the effect of protein transduction domain-hepatitis B virus core antigen (CTP-HBcAg18-27)-Tapasin fusion protein-induced specific cytotoxic T lymphocyte (CTL) response on hepatitis B virus (HBV) replication in HBV transgenic mice.


METHODS
Twenty HBV-transgenic mice were randomly divided into two groups for a 3-week course of once weekly subcutaneous immunizations with either CTP-HBcAg18-27-Tapasin fusion protein or CTP-HBcAg18-27. Mice administered isotonic saline served as blank controls. Expressions of cytokines in splenocytes were analyzed by flow cytometry. Serum levels of hepatitis B surface antigen (HBsAg) and HBV DNA were determined by microparticle enzyme immunoassay and real-time fluorescent PCR assay, respectively. Expression of HBsAg in hepatic tissues was detected by immunohistochemistry.


RESULTS
Immunization with 100 mug of CTP-HBcAg18-27-Tapasin fusion protein led to a significant increase in proportions of CTLs in spleen (2.70%+/-0.20% vs. 50 mug of CTP-HBcAg18-27-Tapasin: 1.66%+/-0.53%, 50 mug of CTP-HBcAg18-27: 1.26%+/-0.56%, and blank controls: 0.75%+/-0.71%; F = 741.45, P = 0.000) and up-regulation of inflammatory cells in hepatic tissue. In addition, both immunizations of CTP-HBcAg18-27-Tapasin led to significant decreases in serum HBsAg and HBV DNA levels compared to those in the CTP-HBcAg18-27 group.


CONCLUSIONS
HBV-related modification of the expression of the molecular chaperone Tapasin may affect its interaction with intracellular antigen peptides, thereby leading to increases the number of specific CTLs in the spleen, decreases in serum HBsAg and HBV DNA levels, and down-regulation of HBsAg expression in hepatic tissue. These results obtained in HBV-transgenic mice suggest that the CTP-HBcAg18-27-Tapasin fusion protein has anti-HBV activity.
Department of Infectious Disease,Shanghai JiaoTong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
Yuyan
Y
Tang
Xiaohua
X
Chen
Liqin
L
Zhou
Meng
M
Zhuo
Guoqing
G
Zang
Zhenghao
Z
Tang
Yongsheng
Y
Yu
D000818:Animals; D004279:DNA, Viral / Q000097:blood; D005260:Female; D006509:Hepatitis B / Q000276:immunology*; D006512:Hepatitis B Core Antigens / Q000235:genetics; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000502:physiology*; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014162:Transfection; D014779:Virus Replication
D004279:DNA, Viral; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins; C107762:tapasin