3.4. Anti-allergic effects of L. plantarum SY11 and L. plantarum SY12
NO production and mechanism of regulation of the cytokines TNF-α, iNOS, and COX-2 in Raw 264.7 cell lines was investigated to verify their anti-allergic effects. Table 2 shows that L. plantarum SY11 and L. plantarum SY12 decreased NO production in Raw 264.7 cells, whereas NO production showed almost no change with L. acidophilus CH-2 (data not shown). RT-PCR analyses revealed that L. plantarum SY11 and L. plantarum SY12 inhibited the LPS-induced expression of TNF-α, iNOS, and COX-2 at the mRNA level, whereas L. acidophilus CH-2 did not ( Fig. 1). These results suggest that L. plantarum SY11 and L. plantarum SY12 have anti-allergic effects, and that such immunomodulatory effects are species-dependent. Enterococcus faecalis YM-73, L. rhamnosus GG, and B. lactis Bb-12 have been reported to exhibit Th2 downregulatory effects, as seen in our results ( Cross, 2002 and Ou et al., 2011).