Analysis of the Th1/Th2 reaction in the immune response induced by EV71 inactivated vaccine in neonatal rhesus monkeys.

Although clinical trials for the enterovirus type 71 (EV71) inactivated vaccine have been progressing, the potential mechanism of EV71 infection and its associated pathogenesis are not well-characterized in terms of comprehensive analysis of the induced immune response, which is generally recognized as an important indicator of the safety of vaccines. To investigate the Th1/Th2 response following viral challenge in neonatal rhesus monkeys immunized with different doses of EV71 inactivated vaccines, the variety of different Th1 and Th2 cytokines in the organs or tissues of the monkeys were identified. The results suggest that depending on the viral challenge, the Th1/Th2 reaction induced by different doses of EV71 inactivated vaccine varies. More specifically, there is an enhanced immune response in 80EU- and 1280EU-immunized monkeys, whereas 320EU immunization induces a mild response. Although there is no direct impact on the variation in immune protection induced by the vaccine, the Th1 reaction functions in T-cell cytotoxicity, which will aid further investigation of the pathogenic characteristics of small pathological changes in the central nerves system (CNS) likely induced by the Th1 response.