Robust assay for analyzing the neutralization activity of serum specimens against hepatitis B virus.

Anti-HBs is a well-known marker of protective capability against HBV. However, little is known about the association between the qAnti-HBs determined by immunoassays and the neutralization activity (NAT) derived from functional assays. We developed an assay for direct measurement of the NAT of human sera.

Long-term HEV carriers without antibody seroconversion among eligible immunocompetent blood donors.

Hepatitis E virus (HEV) is emerging as a potential threat to the safety of blood transfusions. In many countries and regions endemic for HEV, such as China, blood donors are not routinely tested for HEV infection. In this study, 11747 eligible blood donors were screened for anti-HEV immunoglobulin M (IgM)/immunoglobulin G (IgG) and HEV RNA and antigen in China.

[Epidemiologic Survey of Blood Donors with HBsAg⁻/HBV DNA⁺ in Chinese Xiamen Area].

Objective: To understand the characteristics of infections from blood donors with HBsAg⁻/HBV DNA⁺ in Xiamen area.

Methods: Donors in Xiamen area were assayed by routine ELISA and those with negative results were tested by nucleic acid amplification testing (NAT). HBsAg⁻/HBV DNA⁺ samples were tested by quantitative detection of HBV DNA.

[Quantitation of HTLV-I proviral load using real-time quantitative PCR with Taqman MGB probe].

A quantitative real-time PCR assay was developed to measure the proviral load of human T-lymphotropic virus type I (HTLV-I) in peripheral blood. The technology utilizes special primers and Taqman MGB fluorescence probe to measure amplification products from the gag-pro-pol polyprotein gene of HTLV-I. HTLV-I copy number was normalized to the amount of cellular DNA by quantitation of the beta-actin gene, The amplification system was sensitive to detect 5 copy/microL.

Molecular characteristics of occult hepatitis B virus from blood donors in southeast China.

The characteristics of 30 carriers with occult hepatitis B virus (HBV) infection (OBI) were compared with those of 30 individuals diagnosed as being HBV carriers at the time of blood donation, 60 asymptomatic carriers, and 60 chronic hepatitis patients. The prevalence of genotype C was significantly higher in carriers with OBIs than in any other HBsAg-positive (HBsAg(+)) group (P < 0.001).

[Surveillance for occult HBV infection and HBsAg variants in blood donors].

Occult hepatitis B virus (HBV) infection status of blood donors in a southern city in China was investigated by immunological assays and nucleic acid testing. Overall, 17 (0.19%, 95% CI: 0.

Specific cellular immune response in hepatitis E patients.

Aims: To evaluate the specific T cell response together with IgM anti-hepatitis-E-virus (HEV) antibodies in acute hepatitis E (HE) patients.

Methods: Blood samples were collected from 11 HE patients every week and assayed for routine blood investigation after onset of disease until their convalescence. Peripheral blood mononuclear cells were separated from some of the blood samples (1-3 samples per patient) and tested for specific T cell response by enzyme-linked immunosorbent spot assay and IgM anti-hepatitis E virus by enzyme-linked immunosorbent assay.

Immune response induced by a different combined immunization of HBsAg vaccine.

Aims: To evaluate the immune responses induced by different combined immunizations of HBsAg protein vaccine (P), recombinant vaccinia virus vaccine (V) and DNA vaccine (D).

Methods: Balb/c mice were primed by one of the three HBsAg vaccines P, V or D and boosted by the same or another, thus nine immune combinations were constructed. Titers of anti-HBsAg IgG and their sub-isotypes were determined by ELISA.

Difference of T cell and B cell activation in two homologous proteins with similar antigenicity but great distinct immunogenicity.

The candidate particulate hepatitis E vaccine, HEV 239, has been shown to be an efficacious vaccine in primates, and clinical study to date shows it to be safe and immunogenic for humans. The antigenicity of HEV 239 is virtually identical to its N-terminal 26 amino acids truncated protein, E2, which is not particulate but soluble. However, HEV 239 is over 200 times more immunogenic than E2.

[Immune response induced by combinant immunization of different HBsAg vaccines in mice].

Aim: To investigate the specific humoral and cellular immune response induced by prime-boost immunization of HBsAg protein vaccine (P), recombinant vaccinia virus vaccine (V) and DNA vaccine (D) in mice.

Methods: Groups of BALB/c mice were primed by one of the three vaccines P, V or D and boosted by another vaccine at 2, 5, 8 and 11 week later, thus 9 immune combinations were made: PP, PV, PD, VP, VV, VD, DP, DV and DD. Serum samples were collected at week 2, 5, 8 and 11 and levels of anti-HBsAg IgG antibodies and their sub-isotypes were determined.

Hydrophobicity of reactive site loop of SCCA1 affects its binding to hepatitis B virus.

Aim: To investigate the role of SCCA2 and other SCCA1 molecules in the process of hepatitis B virus (HBV) binding to mammalian cells.

Methods: SCCA1 and SCCA2 were isolated from HepG2. Binding protein (BP) genes were obtained through PCR.

[Hydrophobicity of reactive site loop of SCCA1 affects its binding to HBV].

Squamous cell carcinoma antigen 1 (SCCA1), a member of the ovalbumin family of serine protease inhibitors, includes several variants. It was reported that expression of two SCCA1 (BP and AJ515706) in cells results in increased binding of HBV to these cells by the interaction of the expressed BP and AJ515706 with HBV pre-S1 domain. In this study, a SCCA1 (A1) was isolated from HepG2, but it appears to lack this ability.

[Detection of hepatitis E virus on a blood donor and its infectivity to rhesus monkey].

Objective: To understand the infectivity and pathogenicity of the plasma of hepatitis E virus (HEV) viremia to primate animals.

Methods: RNA fragment of HEV genotype IV was detected on one healthy donor who was positive for anti-HEV IgM and negative for anti-HEV IgG. Then 10 ml plasma from above donor was transfused to rhesus monkey to observe its infectivity and pathogenicity.