Lactic acid bacteria (LAB) has been emphasized to provide beneficial function to human gastrointestinal (GI) ecosystem as a probiotic. It has not been well-documented that LAB could modulate immune system in GI tract. The purpose of this study is to determine whether adhesion of three LAB (Lactobacillus casei 3260, Lac. casei 3109 and Lac. GG) on HT29 colon adenocarcinoma cells could change cytokine production pattern (Th1/Th2 profiles) in vitro. Our findings revealed that binding of Lac. casei 3260 and Lac.GG to HT-29 cell induced the increased level of Th1 type cytokine, IL-2 and IFN-γ while it decreased Th2 type cytokines, IL-1β, IL-6, and TNF-α, but not IL-4, implicating that binding of LAB on HT-29 normalized Th1/Th2 profile. In conclusion, as a probiotic, LAB may give a good effect on colon cancer by balancing the Th1/Th2 cytokine profile, but it is critically dependent on binding capacity of LAB to tumor/cancer cells and thus the pattern of cytokine production due to LAB adhesion may be bacterial strain-specific.

Keywords: Lactic acid bacteria, Adhesion, Colon cancer, Cytokines, Th1/Th2 profile