Identification of lactic acid bacteria with reduced inflammatory and enhanced protective properties against influenza virus

Abstract

Lactic acid bacteria (LAB) exert beneficial effects on health by regulating innate immunity in the intestinal tract. Many LAB that demonstrate anti-viral properties depend on the host’s inflammatory responses; however, a few LAB strains have low inflammatory and anti-viral properties. In this study, the LAB strain D279 (NITE_BP-03645, Latilactobacillus sakei ) was isolated from among 741 LAB strains that were analyzed for their ability to induce interleukin 12 (IL-12), and was subsequently characterized. D279 induced the highest levels of IL-12 among the screened LAB. Further, D279 significantly activated anti-viral genes and preferentially induced IFNλ in vitro, which plays a critical role in the epithelial tissue, conferring strong anti-influenza potency without inflammation, whereas IFNα levels were relatively lower. Administration of pasteurized D279 to mice resulted in strong anti-influenza potency, including higher natural killer (NK) cell activity, and a reduced number of viruses in the lung compared to the control. Importantly, no D279-fed mice were sacrificed during the viral infection tests. Taken together, these results suggest that D279 administration confers beneficial effects with reduced inflammation, regulates innate immunity, and may be relevant for commercial use in the future.