LONG-TERM T-CELL-MEDIATED IMMUNOLOGIC MEMORY TO HEPATITIS B VACCINE IN YOUNG ADULTS FOLLOWING NEONATAL VACCINATION

摘要

Background: The long-term duration of cell-mediated immunity induced by neonatal hepatitis B virus (HBV) vaccination is unknown.Objectives: Study was designed to determine the cellular immunity memory status among young adults twenty years after infantile HB immunization.Patients and Methods: Study subjects were party selected from a recent seroepidemiologic study in young adults, who had been vaccinated against HBV twenty years earlier. Just before and ten to 14 days after one dose of HBV vaccine booster injection, blood samples were obtained and sera concentration of cytokines (interleukin 2 and interferon) was measured. More than twofold increase after boosting was considered positive immune response. With regard to the serum level of antibody against HBV surface antigen ( HBsAb ) before boosting, the subjects were divided into four groups as follow: GI, HBsAb titerResults: Before boosting, among 176 boosted individuals, 75 (42.6%) had HBsAb 10 IU/L and were considered seroprotected . Among 101 serosusceptible persons, more than 80% of boosted individuals showed more than twofold increase in cytokines concentration, which meant positive HBsAg -specific cell-mediated immunity. MCL of both cytokines after boosting in GIV were decreased more than twofold, possibly because of recent natural boosting.Conclusions: Findings showed that neonatal HBV immunization was efficacious in inducing long-term immunity and cell-mediated immune memory for up to two decades, and booster vaccination are not required. Further monitoring of vaccinated subjects for HBV infections are recommended.