薬理と治療

Abstract

Objectives The objective of this study was to examine the effect of the beverage containing heat-killed Lactococcus lactis subsp. lactis JCM5805（Lc. lactis JCM5805）on anti-viral immune responses and maintenance of physical conditions. Methods A randomized, double-blind, placebo-controlled, parallel-group trial was conducted. One hundred subjects were divided into 2 groups and took 1 bottle （500 mL）daily of the beverage that did╱did not contain approximately 100 billion heat killed Lc. lactis JCM5805 for 8 weeks. To evaluate anti-viral immune responses, we measured CD86 and HLA-DR expression levels on plasmacytoid dendritic cells（pDC）, which are responsible for regulation of anti-viral immune responses in peripheral blood mononuclear cells（PBMC）and gene expression levels of anti-viral factors in PBMC stimulated by inactivated human influenza A virus（H1N1）. Also, cumulative incidence days of cold︱like symptoms were analyzed to evaluate effects on maintenance of physical conditions. Results After 8 weeks intake period, CD86 and HLA-DR expression levels on pDC in the Lc. lactis JCM5805 group were significantly higher compared to the placebo group. Additionally, gene expression level of ISG15, an anti-viral factor known to be induced by typeⅠ interferon, was significantly higher compared to the placebo group after the intake period. Furthermore, cumulative incidence days of cold-like symptoms during the intake period were significantly lower in the Lc. lactis JCM5805 group compared to the placebo group. Conclusions The beverage containing approximately 100 billion heat-killed Lc. lactis JCM5805 is suggested to be beneficial in enhancing anti-viral immune responses and maintaining physical conditions.