Advanced molecular immunoassay system for immunobiotic lactic acid bacteria using a transfectant of Toll-like receptor 2: Original article

Toll-like receptor 2 (TLR2) is a receptor for a variety of microbial components, and it also mediates activation signals in the cell relating to the innate immune system. In order to evaluate the precise molecular immunoregulation by various strains of lactic acid bacteria (LAB) via TLR2, the swine TLR2 (sTLR2)-expressing transfectant was constructed using human embryonic kidney (HEK) 293 cells. It is demonstrated that intact immunobiotic LAB can induce immune responses through TLR2, and that different nuclear factor-κB (NF-κB) activities of various strains can be accurately detected by sTLR2-expressing HEK293 cells. Furthermore, cellular activation of NF-κB via TLR2 is reflected in enhanced binding and uptake of LAB. The sTLR2-expressing HEK293 cells were also useful for characterizing the expression pattern of type I helper T (Th1) and type II helper T (Th2) cytokines by the stimulation of immunobiotic LAB. These results suggest that sTLR2-expressing HEK293 cells may be useful in certain molecular immunoassay systems for producing new physiologically functional foods with intestinal immunomodulatory abilities, such as the maintenance of Th1/Th2 polarization.