Primary research on cellular immune response induced by live attenuated and inactiveated hepatitis A vaccines / 中华微生物学和免疫学杂志

Objective To evaluate and compare the cellular immune response induced by live at-tenuated and inactivated hepatitis A vaccines. Methods A total of 18 healthy volunteers were enrolled in this study. They were divided randomly into 2 groups and injected by inactivated hepatitis A vaccine and at-tenuated hepatitis A vaccine, respectively. All volunteers' heparinized venous blood was separately collected for testing anti-HAV antibody and the responses of PBMC. The level of IFN-γsecreted by effect T cell was tested by ELISPOT. The percentage of lymphocytes secreting IFN-γ from CD+ and CD8+ T cell was tested by intracellular cytokine staining (ICS) technique. The concentrations of IFN-γ, IL-2, IL-10 and IL-4 in the culture supernatants(grown in the presence or absence of HAV) of the in vitro HAV-primed PBMC were determined by Luminex. Results These two types of vaccines can elicit specific anti-HAY antibodies and no statistical significance between them were observed. At the early stage after inoculation, T cell-mediated immune responses with the secretion of IFN-γ were detected in vaccines inoculated with either type of vac-cines. There was a tendency that the cellular immune responses level induced by inactivated hepatitis A vac-cine was higher than that by live attenuated hepatitis A vaccine during 1 to 3 weeks post-injection. The booster inoculation could significantly increase the level of cellular immune responses induced by the inacti-vated vaccine. Conclusion Both live attenuated and inactivated HAV vaccines can elicit an earlier specific humoral and cellular immune responses, and booster inoculation of inactivated HAV vaccine can rapidly and intensively evoke memory immune responses.

Prevalence and Persistence of Transferred Maternal Hepatitis. A Antibody During The Second Year of Life in Korean Infants / 감염

BACKGROUND: Although the incidence of hepatitis A infection has dramatically declined in developed countries, it is still endemic in many of developing countries, and sporadic outbreak has developed in many middle classed endemic area. Many reports indicate that hepatitis A vaccine would have to be used for widespread immunization of infants, who live in endemic or non-endemic region, for eliminating this infection from circulation. Therefor, the optimal immunization schedule and dose of vaccine should be determined. Recent several studies suggested that high dose hepatitis A vaccination at the time of disappearance of maternal antibody promise protectable immunogenicity in infants. The purpose of our study to find out the prevalence and persistence of maternal HAV antibodies in Korean infants (below 2 years old age). METHODS: 60 mother without past-history of hepatitis A, and 300 heathy infants without history of hepatitis A vaccination and intra-familial contact history of hepatitis A were enrolled in this study. The infants below 2 years old age were classified into 5 groups as following; 0~3 months, 4~6 months, 7~9 months, 10~12 months, 13~24 months, and the number of each group were 60 and sex distribution of each group was equal. Positive rates of Anti-HAV were determined by ELISA. And comparisons of seroprevalence of anti- HAV between groups were analyzed by ANOVA repeated t-test. RESULTS: The seropositive rate of maternal group was 81.7%, and the seropositive rate of 0~3 months of age group was 43.3%. The seroprevalence of anti- HAV significantly declined after 4~6 months of age, and reached below 10% at the age of 7~9 months of age and the low rate of anti-HAV maintained until 2 years old age. And positive rates of anti-HAV showed no significant differences between males and females. CONCLUSION: The results of our study showed that the seroprevalence of anti-HAV significantly declined after 4~6 months of age and the anti-HAV almostly disappeared at 7~9 months of age. So, low seropositive rate of anti-HAV at 7 months of age may justify trials on infant vaccination in Korea.

Hepatitis A antibody in secondary school children in Bangkok.

There are very few published reports on the prevalence of hepatitis A virus in Thailand. This paper is to report the prevalence of the antibody to hepatitis A virus (anti HAV) in secondary school children of different age groups in Bangkok. One hundred seventy two serum specimens from students (age 10-19 years, from M1-M6) were tested for anti HAV by ELISA. The antibodies were detected in 25, 27.3, 31, 30 and 50 percent of children who were in the age groups of 10-11, 12-13, 14-15, 16-17 and 18-19 years respectively. Children with positive anti HAV had histories of jaundice or liver disease more than children without anti HAV. (p < 0.05) The members of the families in both groups (with and without anti HAV) were not significantly different (6.8 + 3.2 vs 7.0 + 2.9) According to our data, two-thirds of secondary school children had no immunity to hepatitis A virus. When hepatitis A vaccine is available, these subjects may be considered a target population for vaccination for disease control.