OBJECTIVETo obtain recombinant baculovirus containing full-length structural gene of HEV and to express HEV structural protein.

METHODSFull-length structural gene of HEV (5147-7126 nt) was inserted into baculovirus expression vector pAcUW51. The recombinant plasmid and Baculo Gold DNA were co-transfected into insect cell line Sf9. Single plaque was picked and amplified and expression of HEV structural protein was tested by SDS-PAGE, Western blot and immunofluorescence methods.

RESULTSSDS-PAGE analysis showed HEV structural protein was highly expressed; Western blot and immunofluorescence assay showed that the expression product could specifically react with HEV positive sera, confirming the protein possessing HEV specific antigenicity.

CONCLUSIONSHEV structural protein was successfully expressed using baculovirus expression system.

Animals ; Baculoviridae ; genetics ; Cells, Cultured ; Gene Expression ; Genes ; genetics ; Genetic Vectors ; Hepatitis E virus ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Viral Structural Proteins ; biosynthesis ; genetics

BACKGROUNDTo obtain thermal stable, soluble, biologically active hepatitis E virus recombinant antigen using thioredoxin fusion expression system.

METHODSHEV ORF2 gene fragment (6964-7126 nt) was inserted into thioredoxin fusion expression vector pThioHisA. The recombinant plasmid was transformed into E. coli BL21 strain. After induction with IPTG, cells were lysed and the supernatant was subjected to 80 degree treatment for 10 minutes. After centrifugation, the supernatant was tested by ELISA.

RESULTSSDS-PAGE analysis showed the thioredoxin. HEV fusion protein was highly expressed and was thermally stable, soluble. HEV specific ELISA confirmed this fusion protein possessing HEV specific antigenicity.

CONCLUSIONSUsing thioredoxin fusion expression system, a soluble, thermal stable, biologically active HEV recombinant antigen was successfully expressed.

Antigens, Viral ; biosynthesis ; genetics ; Gene Expression ; Genetic Vectors ; Hepatitis E virus ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Thioredoxins ; genetics ; Viral Proteins ; biosynthesis ; genetics

OBJECTIVETo evaluate the immunogenicity, safety, and dosage of a new inactivated hepatitis A vaccine administered to young adults.

METHODSOne hundred and four normal adult volunteers, seronegative for hepatitis A virus and hepatitis B surface antigen, were randomly assigned to one of three groups. The high-dose group received a primary dose of 1000 units of the new vaccine, the low-dose group received a primary dose of 500 units of the same vaccine, and the Havrix group received a primary dose of 1440 enzyme-linked immunosorbent assay units of Havrix, a licensed inactivated hepatitis A vaccine. All groups received a booster dose of the same vaccine 6 months after the primary dose. Local and systemic adverse reactions, seroconversion rates, and geometric mean titers of hepatitis A virus antibodies were measured in all three groups.

RESULTSLocal and systemic reaction types and rates were similar in all three groups after primary and booster doses, although local reactions were more frequent in the Havrix group following the primary dose. No serious adverse reactions occurred. One month after the primary dose, the seroconversion rate was 87.5% in the high-dose group, 70.0% in the low-dose group, and 50.0% in the Havrix group (P = 0.001, versus the high-dose group). At month 6 (before administration of the booster dose), seroconversion rates were 96.9% in the high-dose group, 65.0% in the low-dose group (P = 0.0029), and 68.8% in the Havrix group (P = 0.007). All subjects in all groups seroconverted by one month after receipt of the booster dose. Geometric mean titers were similar in all three groups at month 1, but were higher in the high-dose group (264 mIU/ml) than those in the Havrix group (135 mIU/ml) at month 6 (P = 0.0013). One month after the booster dose, geometric mean titers in the high-dose group (2747 mIU/ml) were higher than those in the low-dose group (1657 mIU/ml) (P = 0.0223) or in the Havrix group (1316 mIU/ml) (P = 0.01).

CONCLUSIONSThis new inactivated hepatitis A vaccine is immunogenic and safe; two doses of either 500 or 1000 units can induce hepatitis A virus antibodies well above the protection level.

Adolescent ; Adult ; Hepatitis A Vaccines ; adverse effects ; immunology ; Humans ; Vaccines, Attenuated ; adverse effects ; immunology

BACKGROUNDTo determine the long-term efficacy and persistence of Chinese infants after receiving only active plasma-derived hepatitis B vaccine, and to evaluate if providing booster vaccination after basic hepatitis B immunization is necessary.

METHODSInfants who were born in 1986-1988 in four demonstrative hepatitis B immunization trial areas of Hunan, Guangxi, Hebei and Shanghai after receiving only active plasma-derived hepatitis B vaccination, had been randomly followed up for 15 years. HBsAg,anti-HBs and anti-HBc in 21 680 person-times were tested using commercial SPRIA kits.

RESULTSPrevalence of HBV carriers was less than 1.66% among all children vaccinated with only active plasma-derived hepatitis B vaccine in 4 clinical trial areas. Prevalence of HBsAg did not increase with years after vaccination,90%(95% Cl:83.1%-97.2%) effectiveness of hepatitis B vaccine persisted for 15 years in preventing chronic HBV infection. Carriage, HBV infection and efficacy were not different among all age groups (P>0.05). Seroprotection rate (anti-HBs?10 mIU/ml) and quantity of anti-HBs were significantly decreased with years after vaccination. Seroprotection rates of anti-HBs were 40%-50% and 30%-42% during the 9th-10th year and the 13th-14th ear of vaccination, respectively. Titer of anti-HBs declined?by 90% after 14 years.

CONCLUSIONSThese results showed that long-term efficacy of only active plasma-derived hepatitis B vaccination, which was not affected by decline in seroprotection rate and titer of anti-HBs. For children and adults whose immune status is normal, booster doses of vaccine are not recommended.

Adolescent ; Child ; Child, Preschool ; Follow-Up Studies ; Hepatitis B ; prevention & control ; Hepatitis B Antibodies ; blood ; Hepatitis B Surface Antigens ; blood ; Hepatitis B Vaccines ; immunology ; Humans ; Infant ; Infant, Newborn ; Vaccination

OBJECTIVETo evaluate safety and immunogenicity of inactivated hepatitis A vaccine in HBsAg carriers and healthy children.

METHODSOne hundred and twenty-one healthy children and ten HBsAg carriers, aged 1-10 years HAV susceptible were enrolled in the study. The inactivated hepatitis A vaccine was produced by Tangshan Biogenetic Company. The dosage of the vaccine was 1000 U/Dosage and 500 U/Dosage. The vaccination schedule was six month apart for two injections. The serum anti-HAV level was detected with EIA at one month after first injection and at one and six month after the booster injection, respectively.

RESULTSThe anti-HAV appeared in all the children. One month after the booster injection, the serum anti-HAV level in children vaccinated 500 U/Dosage was 4684.9 mIU and 4535.6 mIU, respectively and in the children vaccinated 1000 U/Dosage, 5399.8 mIU and 7347.1 mIU, respectively. The anti-HAV level was not statistically different between the two groups of children. There was no adverse reaction after the vaccination. The anti-HAV level was still high one year after first injection.

CONCLUSIONSThe data indicated that the safety and immunogenicity of the domestic inactivated hepatitis A vaccine were excellent in both groups of children.

Child ; Child, Preschool ; Hepatitis A Antibodies ; blood ; Hepatitis A Vaccines ; immunology ; Hepatitis B Surface Antigens ; blood ; Humans ; Immunization ; Infant ; Vaccines, Inactivated ; immunology