AIM:To investigate the protective efficacy of H2 strain attenuated live hepatitis A vaccines (H2-strain vaccines) in hepatitis A (HA) outbreaks.METHODS:With the permission of their parents, 5551 pre-school and grade 1...AIM:To investigate the protective efficacy of H2 strain attenuated live hepatitis A vaccines (H2-strain vaccines) in hepatitis A (HA) outbreaks.METHODS:With the permission of their parents, 5551 pre-school and grade 1-3 primary school children were inoculated with 1 dose (10(6.5) TCID(50)) of H2 strain vaccines in a nonrandomized, controlled trial conducted in Fucheng County, Hebei Province in May 1997.Another 6485 children in the same grades and compatible in gender and age were enrolled as controls. Epidemiological and serological survey was conducted to evaluate the protective efficacy of the vaccines. ELISA was used to detect serum IgM anti-HAV.RESULTS:HA outbreak started in early May 1998, peaked in the middle of the same month, and lasted about 80 days. Overall 302 HA cases were found, 192(63.58%) were 5-9 years old. One vaccinee and 25 control cases were found to have hepatitis A, which account for 0.28% (1/356) and 5.92% (25/422) of all vaccinees and controls in the 14 villages, respectively. The protective efficacy of vaccines was 95.27% (95% CI: 85.83%-104.72%). In subjects tested for anti-HAV IgM from 13 villages, 1(0.40%) overt and 11(4.06%) asymptomatic HAV cases were found in 271 vaccinees but 21(6.69%) of overt and asymptomatic ones were found in 314 controls.CONCLUSION:H2 strain vaccines were excellent in preventing overt hepatitis A,but not so effective in preventing asymptomatic hepatitis A virus infection.A booster dose might be needed to get permanent reliable immunity.展开更多
AIM： To construct the plasmid pcHEV23 containing fragments of HEV ORF2 and ORF3 chimeric gene and to assess its ability to elicit specific immunologic response in mice. METHODS： The gene encoding the structural prot...AIM： To construct the plasmid pcHEV23 containing fragments of HEV ORF2 and ORF3 chimeric gene and to assess its ability to elicit specific immunologic response in mice. METHODS： The gene encoding the structural protein of HEV ORF2 fragment and full-length ORF3 was amplified by PCR. The PCR products were cloned into an eucaryotic expression plasmid pcDNA3. The resulting plasmid pcHEV23 was used as a DNA vaccine to inoculate BALB/c mice intramuscularly thrice at a dose of 100 or 200 ug. Mice injected with empty pcDNA3 DNA or saline served as control and then specific immune responses in the mice were detected. RESULTS： After 2-3 times of inoculation, all mice injected with pcHEV23 had anti-HEV IgG seroconversion and specific T lymphocyte proliferation. The lymphocyte stimulation index in the group immunized with pcHEV23 （3.1＋0.49） was higher than that in the control group （0.787±0.12, P〈0.01）. None in the control group had a detectable level of anti-HEV IgG. CONCLUSION： DNA vaccine containing HEV ORF2 and ORF3 chimeric gene can successfully induce specific humoral and cellular immune response in mice.展开更多
基金national ninth five-year study program for tackling key scientific problems,No.03-01-01
文摘AIM:To investigate the protective efficacy of H2 strain attenuated live hepatitis A vaccines (H2-strain vaccines) in hepatitis A (HA) outbreaks.METHODS:With the permission of their parents, 5551 pre-school and grade 1-3 primary school children were inoculated with 1 dose (10(6.5) TCID(50)) of H2 strain vaccines in a nonrandomized, controlled trial conducted in Fucheng County, Hebei Province in May 1997.Another 6485 children in the same grades and compatible in gender and age were enrolled as controls. Epidemiological and serological survey was conducted to evaluate the protective efficacy of the vaccines. ELISA was used to detect serum IgM anti-HAV.RESULTS:HA outbreak started in early May 1998, peaked in the middle of the same month, and lasted about 80 days. Overall 302 HA cases were found, 192(63.58%) were 5-9 years old. One vaccinee and 25 control cases were found to have hepatitis A, which account for 0.28% (1/356) and 5.92% (25/422) of all vaccinees and controls in the 14 villages, respectively. The protective efficacy of vaccines was 95.27% (95% CI: 85.83%-104.72%). In subjects tested for anti-HAV IgM from 13 villages, 1(0.40%) overt and 11(4.06%) asymptomatic HAV cases were found in 271 vaccinees but 21(6.69%) of overt and asymptomatic ones were found in 314 controls.CONCLUSION:H2 strain vaccines were excellent in preventing overt hepatitis A,but not so effective in preventing asymptomatic hepatitis A virus infection.A booster dose might be needed to get permanent reliable immunity.
基金Supported by the Grants from the Natural Science Foundation of Zhejiang Province, No. RC01054, Science Technology Department of Zhejiang Province, No. F11023 and Key Project of Health Bureau of Zhejiang Province
文摘AIM： To construct the plasmid pcHEV23 containing fragments of HEV ORF2 and ORF3 chimeric gene and to assess its ability to elicit specific immunologic response in mice. METHODS： The gene encoding the structural protein of HEV ORF2 fragment and full-length ORF3 was amplified by PCR. The PCR products were cloned into an eucaryotic expression plasmid pcDNA3. The resulting plasmid pcHEV23 was used as a DNA vaccine to inoculate BALB/c mice intramuscularly thrice at a dose of 100 or 200 ug. Mice injected with empty pcDNA3 DNA or saline served as control and then specific immune responses in the mice were detected. RESULTS： After 2-3 times of inoculation, all mice injected with pcHEV23 had anti-HEV IgG seroconversion and specific T lymphocyte proliferation. The lymphocyte stimulation index in the group immunized with pcHEV23 （3.1＋0.49） was higher than that in the control group （0.787±0.12, P〈0.01）. None in the control group had a detectable level of anti-HEV IgG. CONCLUSION： DNA vaccine containing HEV ORF2 and ORF3 chimeric gene can successfully induce specific humoral and cellular immune response in mice.
