INFLUENCE OF MONOACYLTREHALOSE FRACTION OF RHODOCOCCUS-BIOSURFACTANT ON SELECTED INDICATORS OF THE IMMUNE SYSTEM DURING ORAL ADMINISTRATION

AbstractIn the last decade, microbial biosurfactants, along with their traditional use as emulsifiers and solubilizers of hydrophobic substances, have attracted attention as possible biomedicine agents. This is due to the unique manifestations of the biological activity of biosurfactants, not found in synthetic analogs: the ability to exhibit antibacterial, antifungal, antiviral, antitumor or immunomodulatory activity depending on the structure of the molecules. The purpose of the work is to study the effect of Rhodococcus biosurfactant and its monoacyltrehalose fraction on the production of IL-2, IL-4, IFN-γ, IL-17, apoptosis of CD4+ and CD8+ splenocytes with a single oral administration, as well as on humoral and cell-mediated immunity and response host versus graft (HVG) with a course of oral administration in vivo.

It was found that the single oral administration of monoacyltrehalose fraction of Rhodococcus biosurfactant inhibited Con A-induced production of IL-2 and IFN-γ, stimulated IL-4 production and had no effect on levels of IL-17 by splenocytes. Unfractionated Rhodococcus biosurfactant had an inhibitory effect only on IFN-γ production. Oral administration of monoacyltrehalose to mice resulted in a decrease in the percentage of early and late apoptosis of CD8+ lymphocytes, and a decrease in the percentage of late apoptosis of CD4+ T cells. Only the percentage of early apoptosis of CD8+ T lymphocytes was reduced by unfractionated biosurfactant. During 24 hours of culture, we found a single statistically significant effect of reducing the percentage of CD4+ cells in a state of late apoptosis in Con A-stimulated cultures from mice treated with monoacyltrehalose. Under conditions of a course of oral administration, the monocyaltrehalose fraction led to a decrease in the number of nucleated cells in the spleen, inhibition of antibody genesis, as well as suppression of the severity of DTH and RHVG reactions. Thus, oral administration of the monoacyltrehalose fraction of Rhodococcus biosurfactant to mice resulted in decreased Th1 cytokine production, which contributes to a shift in Th0 differentiation towards Th2 cells. The monoacyltrehalose fraction had no apoptogenic effect and, on the contrary, reduced the percentage of late apoptosis of CD4+ and CD8+ T lymphocytes. Therefore, apoptosis is not one of the possible mechanisms of immunosuppression induced by Rhodococcus ruber-biosurfactant components.