Function of Lactobacillus on intestinal mucosal immunity of mice artificially infected with Escherichia coli O157:H7

Abstract:

[Objective] The possible immunomodulatory and anti-infectious effects of Lactobacillus acidophilus KLDS AD1 and Lactobacillus helveticus KLDS 1.8701 were evaluated on the intestinal mucosal immunity in the rats artificially infected with Escherichia coli O157:H7. [Methods] An model animal trial was carried out on rats divided into four treatments, challenged treatment with E. coli O157:H7 for seven days, artificially infected animals treated with L. acidophilus or L. helveticus for another seven days. The intestinal tissue was taken for assaying the secretory immunoglobulin A (SIgA) in intestinal fluid and cytokines (IL-2, IL-4, IL-6, IFN-γ) production in small intestinal tissue by ELISA. [Results] L. helveticus KLDS 1.8701 significantly attenuated the pathogenic influence of E. coli O157:H7 indicated by the high weight gain, better than L. acidophilus KLDS AD1. After treatment with E. coli O157:H7, the levels of SIgA, IL-2 and IFN-γ increased and reached to the maximum value at the third days, decreased at the fifth day, then IL-4 and IL-6 reached to the maximum value and decreased at the seventh day. The levels of SIgA and all assayed cytokines were significantly increased after oral administration of L. acidophilus KLDS AD1 and L. helveticus KLDS 1.8701 at eighth day, and remained higher level than control and pathogenic groups. [Conclusion] L. acidophilus KLDS AD1 and L. helveticus KLDS 1.8701 improved the intestinal mucosal immune by stimulating cytokines and SIgA production, and confered enhanced protection against E. coli O157:H7 infection.