Epitopes ; immunology ; Hepacivirus ; immunology ; Hepatitis C ; immunology ; Humans

Hepatitis C virus (HCV) infection is a worldwide problem in terms of public health. It causes chronic hepatitis C in 60-80% of patients after acute hepatitis C. Chronic hepatitis C can progress to liver cirrhosis and hepatocellular carcinoma. In the present time, combination therapy of pegylated interferon-alpha and ribavirin is the standard therapy for hepatitis C, but it results in sustained virologic response only in 45-80% of treated patients. In addition, there is no available effective vaccine for HCV. To develop effective immunotherapy or preventive vaccine, understanding of the immune response against HCV is prerequisite. Among several components of immune system, T cells play a key role in the clearance of HCV and immunopathology during hepatitis C. In the study of HCV infection, however, the most important limiting factor is the absence of small animal model as only humans and chimpanzees can be infected by HCV. In this review, T cell response against HCV, which has been known from the studies of the HCV-infected patients and chimpanzees, will be discussed in several circumstances, including acute hepatitis C, chronic hepatitis C and recovered status from hepatitis C.
T-Lymphocytes/*immunology ; Humans ; Hepatitis C, Chronic/immunology ; Hepatitis C/*immunology ; Hepacivirus/immunology

In this study, three expression vectors encoding unmodified glycoproteins E1 and E2 from H77 (1a), Hebei (1b) and JFH1 (2a) strains were constructed to form pVRC-H77-E1E2, pVRC-HeBei-E1E2 and pVRC-JFH1-E1E2 expressing constructs. The protein expression was confirmed by immunofluorescene assay(IFA) and Western blot. The Lentiviral vector has the ability to package the cellular membrane into pseudo-particles. The plasmid expressing HCV E1-E2 glycoproteins in native form was co-transfected into 293FT cells with a lentiviral packaging plasmid (pHR'CMV delta R8.2)and a self-inactivated (SIN) transfer plasmid (pCS-CG) containing a reporter EGFP gene to produce infectious HCV pseudo-particles(pp). Flow cytometry assays showed that the HCVpp could infect Huh7 and Huh7-CD81, and the infectivity in Huh7-CD81 was about 2-3 times higher than that in Huh7 cells. Meanwhile, HCVpp could neither infect non-liver cells, for example, the 293 cells, nor HepG2 cell . Titration of HCVpp by p24 ELISA assay or infection assay showed that this HCVpp may contain 5-25 ng/mL p24 or 10(4)-10(5) TU (transducing unit)/ ml. An in vitro HCV neutralizing assays based on HCVpp (1a, 1b, 2a) were then established using AP33, a monoclone antibody with cross-neutralizing ability to different HCV strains. The neutralizing ability of the antibodies from HCV infected patients was further studied with this HCVpp system. In summary, three kinds of HCVpp (1a, 1b, 2a subtype) were successfully developed; In vitro HCV neutralizing assays based on HCVpp and SIN lentiviral system were established. This system paves a way for characterization of early steps of HCV infection (host tropisms, receptor binding, membrane fusion, et al. ) or screening anti-HCV drugs (such as inhibitor to virus entry). This system can be further applied to assess the human immune responses in HCV patients or evaluate HCV vaccine candidates.
Hepacivirus ; immunology ; Hepatitis C Antibodies ; immunology ; Hepatitis C, Chronic ; immunology ; Humans ; Neutralization Tests ; Viral Envelope Proteins ; immunology ; Virion ; immunology

Animals ; Hepacivirus ; genetics ; Hepatitis C ; immunology ; prevention & control ; therapy ; virology ; Humans ; Mutation ; Viral Hepatitis Vaccines ; immunology

Animals ; Antigens, CD ; immunology ; Cytokines ; metabolism ; Hepacivirus ; immunology ; Hepatitis C ; immunology ; prevention & control ; virology ; Hepatitis C Antibodies ; biosynthesis ; immunology ; Hepatitis C Antigens ; immunology ; Humans ; Killer Cells, Natural ; immunology ; T-Lymphocytes ; immunology ; metabolism ; T-Lymphocytes, Regulatory ; immunology ; metabolism ; Viral Proteins ; immunology

OBJECTIVETo observe the effect of hepatitis virus B on the detection rate of core antigen of hepatitis virus C in sera of chronic hepatitis C patients.

METHODHCVcAg and HCV RNA in sera were detected in 88 patients with chronic hepatitis C and 62 patients co-infected with HCV and HBV. At the same time, HBV DNA and HBeAg in sera were detected in 62 patients infected with HCV and HBV. Then we analyzed the correlation between HCVcAg and HBeAg/HBV DNA. The detection rates of HCVcAg in 88 patients with chronic hepatitis C and 62 patients co-infected with HCV and HBV were 72.7% (64/88) and 38.7% (24/62), respectively (x2 = 17.358, P less than 0.01).

RESULTSThe detection rates of HCV RNA in 88 patients with chronic hepatitis C and 62 patients co-infected with HCV and HBV was 81.8% (72/88) and 53.2% (33/62)respectively (x2=20.110, P less than 0.01). In 62 patients infected with HCV and HBV, the detection rate of HCVcAg in HBeAg positive patients and HBeAg negative patients were 28.6% (12/42) and 60% (12/20), respectively (x2 = 7.547, P = 0.011). Moreover, the positive rates of HBV DNA in HBeAg positive patients and HBeAg negative patients were 42.9% (18/42) and 80% (16/20), respectively (P more than 0.05). The detection rates of HCVcAg in HBV DNA positive patients and HBV DNA negative patients were 39.1% (18/46) and 37.5% (6/16), respectively (x2 = 0.013, P = 0.908). Compared with the detection rates of HCVcAg in patients only infected with HCV, the detection rate of HCVcAg in HBeAg or HBV DNA negative patients infected with HCV and HBV were 60% (12/20) (x2 = 1.266, P = 0.261) and 37.5% (6/16) (x2 =7.635, P less than 0.01), respectively.

CONCLUSIONThe detection rate of HCVcAg in patients infected with HCV and HBV is relatively low. The reason is possibly that HBeAg inhibits duplication of HCV and decreases the expression of HCVcAg.

Coinfection ; immunology ; virology ; DNA, Viral ; Hepacivirus ; immunology ; Hepatitis B ; immunology ; virology ; Hepatitis B virus ; Hepatitis C Antigens ; blood ; Hepatitis C, Chronic ; immunology ; virology ; Humans

OBJECTIVETo investigate the correlation between impaired non-viral specific immune function of dendritic cell (DC) and viral clearance and cytotoxic T lymphocyte (CTL) response to HBV or HCV in patients with HBV and HCV coinfection.

METHODSTwenty-five patients with HBV and HCV coinfection were investigated in this study. In 1994 and 2002, biochemical and virological markers and quantitative serum HBV DNA and HCV RNA levels were detected in these patients. According to the virus clearance status, these patients were divided into 4 groups: 14 patients with both HBV and HCV clearance (Group A), 6 patients with HCV clearance only (Group B), 3 patients with HBV clearance only (Group C), and 2 patients with persistent infection of HBV and HCV (Group D). Phenotypes and immune functions of monocyte-derived DCs were compared between these groups. 51Cr release assay were used to measure CTL response to epitopes derived from HBV, HCV or influenza virus (as positive control) in HLA-A2+ patients.

RESULTSImpaired non-viral specific immune functions of DCs were observed in group B, C and D compared with group A and normal donors (Group N). These impaired functions included CD86 decreasing expression and lower capacity to stimulating allogenic T cells and uptaking antigen. The specific CTL response to HBV- and HCV-derived peptides could be induced in group A (12/12). The specific CTL response to HBV-derived peptides or to HCV-derived peptides could be induced in group C (3/3) or B (5/5), respectively. But the specific CTL response to both of two HBV-derived peptides or two HCV-derived peptides could not be induced in group C (0/3) or B (0/5), respectively. And no CTL response to HBV or HCV-derived peptides could be induced in groups D (0/1) and N (0/4).

CONCLUSION1. The results suggest that specific CTL response to HBV or HCV play a vital role in the viral clearance. 2. The DCs with impaired non-viral specific immune functions exist in chronic patients with HBV and/or HCV infection, but do not interfere with clearance and CTL response to HBV or HCV. It is reasonable to speculate that impaired functions of DCs result from viral infection.

Adult ; Dendritic Cells ; immunology ; Female ; Hepacivirus ; immunology ; Hepatitis B virus ; immunology ; Humans ; Immunophenotyping ; Lymphocyte Culture Test, Mixed ; Male ; Middle Aged ; T-Lymphocytes, Cytotoxic ; immunology

Hepatitis C virus (HCV) core protein is considered to be an attractive candidate for development of protective HCV vaccines. However, this protein may attenuate the induction of systemic immune responses due to its immunomodulatory properties. In this study, we constructed a HCV core gene-containing eukaryotic expression plamid pCI-C, and an in vivo-inducible prokaryotic expression plasmid pZW-C, and transformed the recombinant plasmids into an attenuated Salmonella typhimurium aroA strain SL7207. The resulting bacterial strains SL7207/pCI-C and SL7207/pZW-C were used to orally immunize BALB/c mice, and the immune responses specific to HCV core protein were assessed. Immunization with the recombinant bacteria SL7207/pCI-C led to a persistent drop in percentage of CD3 CD4 T cells, and induced a weak anti-core IgG production. Splenocytes from SL7207/pCI-C immunized mice developed a relatively weak proliferation response and inferior cytotoxic activity compared to those from the mice immunized with bacteria SL7207/pZW-C. Boost immunization with SL7207/ pCI-C yielded limited improvement in immune strength, while the boost with bacteria SL7207/pZW-C significantly enhanced the immune response. These results suggest that de novo synthesis of native HCV core protein may blunt the induction of immune responses. Attenuated S. typhimurium carrying HCV core protein could efficiently activate systemic cellular and humoral responses, and may be a promising strategy for the development of core-based HCV vaccines.
Animals ; Hepacivirus ; genetics ; immunology ; Mice ; Plasmids ; genetics ; Salmonella typhimurium ; genetics ; metabolism ; Vaccines, DNA ; immunology ; Viral Core Proteins ; genetics ; immunology ; Viral Hepatitis Vaccines ; genetics ; immunology

Animals ; Female ; Hepacivirus ; immunology ; Hepatitis C ; prevention & control ; Mice ; Mice, Inbred BALB C ; T-Lymphocytes, Cytotoxic ; immunology ; Vaccination ; Vaccines, DNA ; immunology ; Viral Hepatitis Vaccines ; immunology

Cloning, Molecular ; Escherichia coli ; genetics ; Hepacivirus ; genetics ; Humans ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Viral Nonstructural Proteins ; biosynthesis ; genetics ; immunology