Сomparative characteristics of cytokine profile induced in vitro by supernatants of industrial and intestinal strains of bifido- and lactobacteria

The immunomodulatory properties of probiotics largely depend on the metabolites secreted into the culture medium, which is studied as a cell-free supernatant and referred to as postbiotics. The aim of the present work was to conduct screening of cytokine profiles for intestinal strains of Bifidobacteria and Lactobacillus by testing it with mononuclear cells from human peripheral blood, and comparing it with cytokine profile of typical industrial bacterial strains, in order to select promising strains with anti-inflammatory properties as potential pro-/postbiotics. The cytokine profile of probiotic and intestinal strains of Bifidobacteria and Lactobacillus isolated from the large intestine of healthy people was determined by the biological effects of cell-free supernatants on the production of pro- (IFNγ, TNFα, IL-17, IL-8, IL-6) and anti-inflammatory (IL-10, IL-1ra) cytokines in the in vitro model of peripheral mononuclear cells isolated from human blood. We have established three types of effects on the cytokine profile: type 1 was characterized by a predominant increase in IL-10 production, and a decrease in TNFα, IL-17, IL-6; type 2, produced a decrease, mainly at the level of pro-inflammatory cytokines; type 3 caused a decreased secretion of both pro- and anti-inflammatory cytokines. Among type 1 and type 2 cultures, the Bifidobacterium bifidum ICIS-202 and Bifidobacterium bifidum ICIS-504 strains had high anti-inflammatory potential, capable of both suppressing the secretion of pro-inflammatory cytokines, and enhancing the production of anti-inflammatory cytokines. The supernatant of L. ruminis ICIS-540 strain showed a promising effect, i.e., it repeatedly reduced the level of early proinflammatory TNFα cytokine. The anti-inflammatory activity of these strains was not inferior, but, in relation to individual cytokines (IL-10, TNFα, IL-6), was superior to the known probiotic bacterial cultures. The in vitro testing of metabolic products in bacterial supernatants enabled us to select promising strains of L. ruminis ICIS-540, B. bifidum ICIS-504 and B. bifidum ICIS-202 which may be suitable for implementation of bacterial preparations with anti-inflammatory activity.