폐렴구균 DNA 백신의 유효성 평가

Evaluation of a Streptococcus pneumoniae DNA Vaccine Efficacy

Streptococcus pneumoniae is the leading cause of pneumonia and bacterial meningitis. The current polysaccharide vaccine has been reported ineffective in elderly adults and children less than 2 years of age. Thus, in recent many researchers have been focusted on a different approach, DNA vaccine. In our laboratory, we developed a Streptococcus pneumoniae DNA(SPDNA) vaccine. This SPDNA vaccine was formulated by inserting the resion encoding part of the capsule in the S.pneumoniae into the LAMP-1. In present work, with use of the SPDNA vaccine we attmpted to to establish a certain methodology useful for evaluation of effectiveness and immunoresponse of a DNA vaccine. Results showed that the subcutaneous route was the most effective for production of antisera specific for S. pneumoniae in mice. By isotyping analyses, IgM, IgG1, IgG2a, and IgG2b were determined. In addition, INF-γ and IL-4 were predominantly detected. Combination of those data resulted in a pattern of IgG1IL-4, which indicates the immunity towards the Th1 response predominantly. Furthermore, the SPDNA vaccination induced resistance of the CD4+T lymphocyte-depleted mice against disseminated pneumococcal infection. These data appear to be possibly due to activation of CD8+T cell-activation. Taken together, this methodology can be applied for evaluating efficacy and mode of action of a DNA vaccine as minimum criteria.