Suppressive Effect of Lactococcus lactis subsp. cremoris YRC3780 on a Murine Model of Japanese Cedar Pollinosis

Accumulating evidence suggests that Lactococcus lactis subsp. cremoris YRC3780 isolated from kefir has the potential to alleviate allergic responses. Herein, we investigated the effect of YRC3780 on a murine model of Japanese cedar pollinosis (JCP). BALB/c mice immunized with cedar pollen extract (CPE) exhibited an increase in serum immunoglobulin E and developed nasal inflammatory responses including sneezing, nasal hyperresponsiveness, and nasal eosinophil accumulation upon intranasal allergen challenge. These responses were suppressed by the oral administration of YRC3780, although the effects on CPE-induced sneezing response and eosinophil infiltration were not statistically significant. Total fecal microbiota diversity was not affected by allergen immunization and challenge or by YRC3780 administration. However, the abundances of Bifidobacteriales, Veillonellaceae, Lactococcus, and Lactococcus lactis were larger and that of Bacteroides was smaller in YRC3780-treated mice compared with those in CPE-challenged and YRC3780-untreated mice. Our findings suggest the usefulness of YRC3780 for alleviating JCP.

The impact of the 67kDa laminin receptor on both cell-surface binding and anti-allergic action of tea catechins

Here, we investigated the structure-activity relationship of major green tea catechins and their corresponding epimers on cell-surface binding and inhibitory effect on histamine release. Galloylated catechins; (-)-epigallocatechin-3-O-gallate (EGCG), (-)-gallocatechin-3-O-gallate (GCG), (-)-epicatechin-3-O-gallate (ECG), and (-)-catechin-3-O-gallate (CG) showed the cell-surface binding to the human basophilic KU812 cells by surface plasmon resonance analysis, but their non-galloylated forms did not. Binding activities of pyrogallol-type catechins (EGCG and GCG) were higher than those of catechol-type catechins (ECG and CG). These patterns were also observed in their inhibitory effects on histamine release. Previously, we have reported that biological activities of EGCG are mediated through the binding to the cell-surface 67kDa laminin receptor (67LR). Downregulation of 67LR expression caused a reduction of both activities of galloylated catechins. These results suggest that both the galloyl moiety and the B-ring hydroxylation pattern contribute to the exertion of biological activities of tea catechins and their 67LR-dependencies.