Lactobacillus gasseri cell fraction, which has dietary experience and is safe for long-term intake, was found to suppress delayed hypersensitivity reactions. Therefore, the present invention provides a delayed-type hypersensitivity reducing agent containing a bacterial cell fraction of Lactobacillus gasseri. The present invention also provides a food composition for reducing delayed type hypersensitivity containing the bacterial cell fraction of Lactobacillus gasseri. In the present invention, it has been clarified that the RNA fraction of the bacterial cell fraction exhibits a particularly high effect of suppressing delayed type hypersensitivity reaction.食経験があり長期間摂取における安全性が明確なLactobacillus gasseriの菌体画分が、遅延型過敏性反応を抑制することが明らかとなった。したがって本発明は、Lactobacillus gasseriの菌体画分を含有する遅延型過敏症の軽減剤を提供する。また、当該Lactobacillus gasseriの菌体画分を含有する遅延型過敏症軽減用の食品組成物を提供する。なお本発明では、当該菌体画分のうちRNA画分が、特に高い遅延型過敏性反応の抑制効果を示すことが明らかとなった。
