IMMUNOREGULATORY PROFILE OF MICROSYMBIONTS OF THE INTESTINAL HUMAN BIOTOPE

Abstract

Aim. To study in comparison immunoregulatory properties of dominant and associative microsymbionts metabolites in human large intestine’s eubiosis and dysbiosis. Materials and methods. 260 strains of bifidobacteria used as dominant microbiota, 132 cultures of conditionally pathogenic bacteria and fungi used as associative microsymbionts from 122 intestinal microsymbiocenoses. The cytokines production was studied in cultures of mononuclear cells co-cultivated with microsymbionts’ supernatants. The results were processed statistically (Statistica 10.0). Results. In eubiosis, dominant and associative microsymbionts showed immuno regulatory properties heterogeneity. In the case of phlogogenic cytokines, the associates equally exhibited stimulation / suppression / no effect on cytokines, except for enterococci and bacteroids, stimulating IL-8 secretion, and lactobacilli, inducing IFNy. Dominants were characterized by a unidirectional effect: IL-10 secretion stimulation and TNFa, IFNy and IL-17suppression, while retaining the induction of IL-10 in dysbiosis. In contrast, supernatants of the associates combined the opposing cytokines production: the early proinflammatory cytokine TNFa, the immunoregulatory cytokine IFNy and the antiinflammatory cytokine IL-10. Conclusion. Intestinal homeostasis in eubiosis is supported by differentiated effects of microsymbionts’ metabolites on the production of antiinflammatory, immunoregulatory cytokines with the formation of an optimal balance, limiting inflammatory and autoimmune reactions. The dominance of the immunoregulatory properties remains intact in the conditions of dysbiosis, and the variety of effects on pro-/antiin-flammatory cytokines is limited in the associates.

Keywords

• bifidobacteria
• associative microsymbionts
• symbiosis
• eubiosis
• dysbiosis
• cytokines
• immune intestinal homeostasis