Potential of selected strains of lactic acid bacteria to induce a Th1 immune profile

Lactic acid bacteria (LAB) might switch the Th2 biased immune response in allergic patients towards a balanced Th1/Th2 immune profile, leading to amelioration of allergy. To select strains of LAB that could be of potential application for foods in controlling allergy, 35 bacterial strains were screened in vitro using murine splenocytes and peritoneal exudate cells (PECs). Streptococcus thermophilus AHU1838 (FERM AP-21009), and Lactobacillus paracasei subsp. casei AHU1839 (FERM AP-21010) enhanced the secretion of Th1 cytokines such as interferon-gamma (IFN-gamma) and interleukin-12 (IL-12). The two strains of LAB also up-regulated the expression of CD40, and CD86 in dendritic cells (DCs), and activated cytotoxic T lymphocytes (CTL). These two strains could therefore be used in producing fermented food products that can enhance the Th1 immune profile which is important in ameliorating allergy.