Effect of Lacticaseibacillus rhamnosus and Lactiplantibacillus plantarum isolated from food and human origin on reduction of IgE-dependent hypersensitivity in Balb/c mice.

Capacity and ability of Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus probiotic strains isolated from some human and food sources were evaluated for modulating and regulating the immune system against hypersensitivity type 1 (dependent on IgE). In this study, given the probiotic properties of the strains and the use of mouse models, the strains were orally administered (1×109 cfu/ml) during 45 days with gavage needles. Levels of total IgE antibodies, cytokines TGF-β, INF-ɤ, and IL-4 were measured by ELISA and compared with control groups. In addition, the nasopharyngeal lavage (total and differential count) was evaluated. Among the strains, Lactiplantibacillus plantarum a7 and Lacticaseibacillus rhamnosus M1 had the highest suppression of IL-4 cytokine production in splenocytes from ovalbumin-sensitized mice in vitro. Also, a7 and M1 had a significant (P < 0.0001) effect on reducing total IgE levels compared to the control group (OVA). Further, Lactiplantibacillus plantarum M8, a7 and M1 enhanced the production of INF-ɤ and TGF-β cytokines. Examination of nasal lavage results revealed that the total cell count in the a7, M1 and Lacticaseibacillus rhamnosus RHM groups and eosinophil cells in Lactiplantibacillus plantarum LF57, a7, and M1 significantly decreased compared to the control group. It was observed oral feeding of the isolated strains had a beneficial effect on reducing the total count on Plate Count Agar (PCA) and Mac Conkey Agar in mice feces during 7 days. M1 and a7 showed the highest level of Lactic Acid Bacteria at 7.28 and 6.9 Log cfu/g on day14, respectively. In conclusion, the animals that received the strains M1 and a7 (isolated from cow's milk and infant's small intestine) had the highest count of lactic acid bacteria in the mice gastrointestinal tract on day 14 (7.28 and 6.9 Log cfu/g), respectively. In addition, the mentioned strains can modulate immune system of mice by suppressing IL-4 production, increasing INF-ɤ and TGF-β cytokines, and reducing total IgE levels.