Modulation of lymphocyte subpopulations in the small intestine of mice treated with probiotic bacterial strains and infected with Trichinella spiralis

Abstract

Aims: To study the local intestinal lymphocyte immunity in mice with trichinellosis affected by probiotic bacteria.

Methods and results: Enterococcus faecium CCM8558, Enterococcus durans ED26E/7, Limosilactobacillus fermentum CCM7421 and Lactiplantibacillus plantarum 17 L/1 were administered daily (10⁹ CFU ml^-1 ) and mice were infected with Trichinella spiralis (400 larvae) on the 7th day of treatment. T. spiralis infection significantly inhibited lymphocyte subpopulations from 5 to 25 days postinfection (dpi). L. fermentum CCM7421 and L. plantarum 17 L/1 restored the CD4⁺ T cell numbers in the epithelium and lamina propria at the control level from 11 dpi. All strains stimulated the CD8⁺ T cells numbers in infected mice, which were restored in the lamina propria on 11 dpi and in the epithelium only on 32 dpi. B cells (CD19⁺ ) inhibition after T. spiralis infection was not affected by treatment till 25 dpi.

Conclusions: The strain-specific immunomodulatory effect of tested bacteria was confirmed. L. fermentum CCM7421 and L. plantarum 17 L/1 showed the greatest immunomodulatory potential on CD4⁺ and CD8⁺ T lymphocytes in trichinellosis. E. faecium CCM8558 and E. durans ED26E/7 activated only CD8⁺ T cells in the lamina propria.

Significance and impact of the study: Positive modulation of the gut lymphocyte immunity in T. spiralis infection with bacterial strains showed their beneficial effect with the host's antiparasitic defence.

Keywords: T. spiralis; E. durans ED26E/7; E. faecium CCM8558; L. fermentum CCM7421; L. plantarum 17 L/1; intraepithelial lymphocytes; lamina propria lymphocytes; mice.