Occult HBV infection is characterized by the absence of serum HBsAg with persistence of low level of intrahepatic HBV DNA. Several suggested mechanisms for the origin of occult HBV infection include strong suppression of viral replication and gene expression, mutation in the regulatory regions of HBV genome, formation of immunoglobulin-bound HBsAg, viral interference, and blockage of HBsAg secretion from infected hepatocytes. Standardized assays are not yet available, and sensitive HBV DNA amplification assay is necessary for the diagnosis of cryptic infection. Detection rate of HBV DNA is highest in IgG anti-HBc positive population. However, neither anti-HBc nor anti-HBs can be detected in a significant proportion of infected persons. Occult HBV infection occurs in a number of clinical settings and is highly prevalent in HCV-infected patients as well as in patients with cryptogenic chronic liver disease including hepatocellular carcinoma.
DNA, Viral/analysis ; Hepatitis B/*diagnosis/*epidemiology/metabolism ; Hepatitis B Antibodies/blood ; Hepatitis B Core Antigens/immunology ; Hepatitis B Surface Antigens/blood ; Humans

This study was performed to determine the incidence and seroprevalence of hepatitis A virus (HAV) infections in young soldiers in the Republic of Korea Army. From January 2000 through December 2004, a total of 147 hepatitis A cases were reported to the Armed Forces Medical Command. The annual incidence rates were 7.4 per 100,000 persons in 2000, 1.6 in 2001, 4.4 in 2002, 9.8 in 2003, and 6.2 in 2004, based on the reported cases among approximately 500,000 soldiers. All patients were males with a median age of 21 yr (range, 19-27). The most common symptom was nausea (86.5%), and all patients had recovered without complications. In addition, in order to evaluate the seroprevalence of HAV infection in young adults, serum samples were obtained from randomly selected young subjects among those who had been admitted to the Armed Forces Capital Hospital from September 2005 to February 2006. A total of 200 subjects were enrolled in the study to analyze the anti-HAV immune status. The overall anti-HAV IgG seropositive rate was 2% (4/200, 95% CI, 0.60-5.21%). Given the changing epidemiology of the disease and the associated increase in morbidity, it was suggested that the routine HAV vaccination for Korean military personnel might be necessary.
Adult ; Hepatitis A/*blood/*epidemiology/immunology ; Hepatitis A Antibodies/immunology ; Hepatitis A virus/*metabolism ; Humans ; Immunoglobulin G/blood ; Incidence ; Korea ; Male ; Military Personnel ; Seroepidemiologic Studies

OBJECTIVETo identify human single chain Fv antibody (ScFv) against hepatitis B viral surface antigen.

METHODSThe recombinant phages were panned by HBsAg which was coated in a microtiter plate, after five rounds of biopanning, 56 phage clones were identified specific to HBsAg. The specificity of ScFv was evaluated by ELISA and immunohistochemistry, respectively.

RESULTSThe data of HB sAg-ScFv DNA digestion and DNA sequencing showed that the ScFv gene is composed of 750 bp. ELISA and immunohistochemistry demonstrated that the human single chain Fv antibody against hepatitis B surface antigen has a specific combination character with hepatitis B surface antigen of different sources and paraffin-embedded patients tissue specimens, it did not react with normal liver tissue and HCV.

CONCLUSIONSThe application of HBsAg specific ScFv in immunohistochemistry was successfully achieved.

Bacteriophages ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Hepatitis B Antibodies ; Hepatitis B Surface Antigens ; immunology ; Hepatitis B, Chronic ; diagnosis ; Humans ; Peptide Library

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

BACKGROUNDTo determine the antigenicity of recombinant hepatitis E virus ORF2 (rHEV ORF2) protein expressed in Pichia pastoris (P. pastoris).

METHODSBy using the rHEV ORF2 protein from E.coli as control, an indirect ELISA was adopted to identify the sensitivity, specificity and stability of rHEV ORF2 protein from P. pastoris in detection of HEV IgM and IgG antibody in sera from patients with hepatitis E. The reactivity of the rHEV ORF2 against 5 HEV ORF2 monoclonal antibodies (McAbs) was also tested.

RESULTSThe minimum concentration of coated antigen with which HEV IgG could be detected was 12.5 ng/ml, while the highest serum dilution to detect both IgM and IgG antibodies against HEV was 1:5 120. No cross-reaction was found with sera from patients with any other types of hepatitis. The 37 degree C acceleration test showed that the rORF2 was highly stable within 12 months at 4 degrees C. The 5 HEV ORF2 McAbs showed better reaction with the rORF2 from P. pastoris, especially that 4B2, 2E2, whose reaction against the rORF2 were 125 and 25 times respectively higher than that of rORF2 from E.Coli.

CONCLUSIONThere may be more extensive conformational epitopes in the rHEV ORF2 from P. pastoris. The excellent antigenicity, sensitivity and stability suggest that it can be served as a new candidate antigen for the development of diagnostic reagents of hepatitis E.

Gene Expression ; Hepatitis Antibodies ; blood ; Hepatitis Antigens ; genetics ; immunology ; Hepatitis E ; immunology ; Hepatitis E virus ; genetics ; immunology ; Humans ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; genetics ; immunology ; Viral Proteins ; genetics ; immunology

OBJECTIVETo explore the conditions for high expression of anti-HBsAg scFv A-15 in E. coli, increase the production of the scFv in the culture medium.

METHODSBy changing induction occasion, concentration of inductor IPTG and induction time, influence of various conditions on expression of anti-HBsAg scFv A-15 was analyzed through ELISA. In addition, the effects of sucrose, glycine and Triton X-100 at different concentrations on the scFv excretion into culture medium was evaluation.

RESULTSThe optimal expression conditions were as follows: the induction was started after culturing for 4 h, the concentration of IPTG was 0.5 mmol/L, and the induction lasted for 8 h. The scFv affinity in culture medium with 0.3 mol/L sucrose, 2% glycine, 1% Triton X-100, 16.78-fold higher, respectively than that without the three chemicals. The final yield of anti-HBsAg scFv A-15 was estimated to be 7.4 mg/L.

CONCLUSIONThe conditions for production of anti-HBsAg scFv A-15 were optimized, which provides a practical method for more efficient production of the scFv in E. coli for further studying structure and function.

Culture Media ; metabolism ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; Genetic Engineering ; methods ; Hepatitis Antibodies ; genetics ; metabolism ; Hepatitis B Surface Antigens ; genetics ; immunology ; Humans ; Immunoglobulin Variable Region ; genetics ; metabolism ; Protein Transport ; Recombinant Proteins ; genetics ; metabolism

OBJECTIVETo prepare streptavidin-tagged hepatitis C virus (HCV) fusion protein and explore its application for the detection of antibody against HCV infection.

METHODSA recombinant plasmid pET-11d-C44P-SA was constructed, which coding a novel HCV diagnostic antigens (C44P) and streptavidin (SA) fusion protein, and the fusion protein was generated with BL21 (DE3) E Coli and identified by Western Blot analysis. Then the fusion protein was purified through the Ni-NTA affinity chromatography and over 90% purity has been achieved. Anti-HCV ELISAs were developed when the fusion protein was used in the biotin-pre-coated microplate or ordinary microplate, and then the sensitivity and specificity of the ELISA were evaluated with confirmed human sera panels.

RESULTSThe fusion protein was expressed in high yields and purified successfully, the ELISA detection of anti-HCV with human sera panel indicated that its sensitivity and specificity is higher when SA-tagged HCV antigen (C44P-SA) coated in biotin-pre-coated microplate, compared to C44P or C44P-SA coated in ordinary microplate.

CONCLUSIONThe sensitivity and specificity of anti-HCV ELISA can be improved when a novel HCV diagnostic antigen fused to SA combined with the biotin- pre-coated microplate. This study laid a foundation for improving the performance of HCV diagnostics.

Antibodies, Viral ; immunology ; Enzyme-Linked Immunosorbent Assay ; Hepatitis C Antigens ; genetics ; immunology ; metabolism ; Recombinant Proteins ; genetics ; immunology ; metabolism ; Streptavidin ; genetics ; immunology ; metabolism

OBJECTIVEInvestigating the distribution of anti-hepatitis E virus (HEV-IgG), anti-human papillomavirus (HPV L1-IgG) and risk factors among female residents in Xinmi County, to explore the influencing factors of HPV vaccine study using HEV vaccinated population as a control.

METHODSA screening study of cervical cancer in Xinmi County, Henan Province, was performed. The information of demographic characteristics and risk factors was collected using standard questionnaire. Nine ml blood was drawn from each woman for enzyme-linked immunosorbent assay to detect HEV-IgG and HPV L1-IgG antibody. Percentile, histogram and binary logistic regression model were used to describe the distribution of risk factors and their correlation to HPV and HEV infection.

RESULTSThe average age of the Xinmi female residents was 47.2 years, their positive rate of HPV L1 antibody was 26.8%, and that of HEV-IgG antibody was 31.0%, both of which were raised with age (P < 0.001). Single factor analysis showed that non-education, low-income and growing age were associated with HEV-IgG antibody positivity, and non-education, lowering ages of first sexual life and growing age were associated with HPV L1-IgG antibody positivity. Multivariable analysis showed that growing age, low-income and work as peasantry were independent risk factors for HEV-IgG antibody positivity, and lowering ages of first sexual life, non-education and growing age were independent risk factors for HPV L1-IgG antibody positivity.

CONCLUSIONSBoth the HEV-IgG and HPV L1-IgG antibodies positive rates increase with age. Age is the common risk factor of HEV-IgG and HPV L1-IgG antibodies in female residents in Xinmi County. The risk factors of HEV-IgG and HPV L1-IgG antibodies have no statistical association, neither cross reaction was found in the HEV-IgG and HPV L1-IgG detection.

Antibodies ; Antibodies, Viral ; China ; Enzyme-Linked Immunosorbent Assay ; Female ; Hepatitis E ; blood ; epidemiology ; Hepatitis E virus ; Humans ; Immunoglobulin G ; metabolism ; Middle Aged ; Papillomaviridae ; Papillomavirus Infections ; blood ; epidemiology ; Papillomavirus Vaccines ; Risk Factors ; Uterine Cervical Neoplasms ; diagnosis

OBJECTIVETo optimize the adsorption condition of cation-exchange chromatographic media Streamline SP for separation and purification of anti-HBsAg Fab fragment from E. coli.

METHODSThe adsorption of the target protein for separation and purification by the cation-exchange chromatographic media Streamline SP was tested using test tube method in balanced buffer solution with different pH values and ion concentrations. The adsorption effect was then verified by cation-exchange chromatography using 1-ml Streamline SP prepacked column and 28-ml Streamline SP self-assembly column.

RESULTSAccording to the experiment results of test tube method, the loading buffer with pH of 4.4 and ionic concentration of 100 to 600 mmol/L could achieve optimal target protein adsorption effect by cation-exchange chromatographic media Streamline SP, as verified by cation-exchange chromatography with 1-ml SP prepacked column and 28-ml Streamline SP self-assembly column.

CONCLUSIONThe optimal condition of cation-exchange chromatography selected by test tube method can be applied for separation and purification of anti-HBsAg Fab fragment from E. coli.

Adsorption ; Cation Exchange Resins ; Chromatography, Ion Exchange ; methods ; Escherichia coli ; genetics ; metabolism ; Hepatitis B Antibodies ; isolation & purification ; metabolism ; Hepatitis B Surface Antigens ; immunology ; Humans ; Immunoglobulin Fab Fragments ; isolation & purification ; metabolism

BACKGROUND/AIMS: The purpose of this study was to characterize the clinical features of acute hepatitis A in Seoul and Gyeonggi province during the recent 2 years. METHODS: We reviewed the medical records of 222 patients who were diagnosed as acute hepatitis A between August 2005 and March 2007 at the Konkuk University Hospital and Korea University, Ansan Hospital. The clinical manifestation, serological tests, and image findings were analyzed. RESULTS: Median age of the patients was 28.1 years and the age groups of highest incidence were the second and third decade. The frequent symptoms were anorexia (66.4%), fatigue (49.2%), fever (47.7%), and abdominal discomfort (42.5%). Fourteen cases (6.3%) showed renal insufficiency, and hemodialysis was performed in one. Cholestatic hepatitis in 2 cases, relapsing hepatitis in 4 cases and prolonged hepatitis in 13 cases were observed. However, there was no case of fulminant hepatitis or death. The underlying diseases including chronic hepatitis B, diabetes mellitus and thyroid disorder did not affect the disease severity of hepatitis A. IgM anti-HAV was not detected initially in 6.7% of the patients. Anti-HEV (IgM) was detected simultaneously in 3 of 150 patients. CONCULSIONS: The age of patients with acute hepatitis A has been increased in the recent years. Most patients recovered uneventfully. However, unusual patterns of severe hepatitis and renal insufficiency occurred in considerable number of cases. Follow-up serologic test for IgM anti-HAV is needed in seronegative cases with hepatitis A
Acute Disease ; Adolescent ; Adult ; Age Distribution ; Child ; Child, Preschool ; Female ; Hepatitis A/*diagnosis/immunology ; Hepatitis A Antibodies/metabolism ; Hepatitis A Virus, Human/immunology ; Humans ; Immunoglobulin M/blood ; Male ; Middle Aged ; Serologic Tests ; Suburban Population