Abstract: Peptidoglycan(PG) was prepared from Lactobacillus sp. Effects of Lactobacillus sp. PG on gene expression of mice immunocytes were studied by using Affymetrix MOE430A Genechip. PG was found inducing expression of molecules related to type 1 immune response. TLR-NF-κB signal pathway would be activated. The expression of Tollip, a negative regulator of TLR-NF-κB signal pathway was modulated by different doses of PG, which could lead to different expressions of different cytikons.