S. V. Gein

In vitro immunomodulating activity of biosurfactant glycolipid complex from Rhodococcus ruber

The biosurfactant glycolipid complex synthesized by Rhodococcus ruber actinobacteria is not toxic and exhibits no appreciable effect on proliferative activity of peripheral blood leukocytes. In the monocyte fraction, the biosurfactant activates the production of IL-1β and TNF-α cytokines without modifying the production of IL-6. In the mononuclear fraction, the glycolipid biosurfactant exhibited no effects on the production of IL-1β, TNF-α, and IL-6. These results indicate good prospects for further studies of immunomodulating and antitumor activities of biosurfactant drug.

In vitro cytokine stimulation assay for glycolipid biosurfactant from Rhodococcus ruber: role of monocyte adhesion

Glycolipid biosurfactant (GLB) from Rhodococcus ruber IEGM 231 was found to stimulate tumor necrosis factor-α (TNF-α), interleukin (IL) -1β and IL-6 production when applied as an ultrasonic emulsion to the adherent human peripheral blood monocyte culture. However, a lack of cytokine-stimulating activity was registered with the GLB applied as a hydrophobic film coating in 24-well culture plates, indicating that it may have been due to its inhibitory effect on monocyte adhesion. The mode of GLB application may therefore play an important role in in vitro assay of immunostimulatory activity of this compound as well as other bacterial glycolipids. Additionally, GLB from R. ruber displayed no cytotoxicity against human lymphocytes and therefore could be proposed as a potential immunomodulating and antitumor agent.

TREHALOLIPID BIOSURFACTANTS FROM NONPATHOGENIC RHODOCOCCUS ACTINOBACTERIA WITH DIVERSE IMMUNOMODULATORY ACTIVITIES

Actinobacteria of the genus Rhodococcus produce trehalolipid biosurfactants with versatile biochemical properties and low toxicity. In recent years, these biosurfactants are increasingly studied as possible biomedical agents with expressed immunological activities. Applications of trehalolipids from Rhodococcus, predominantly cell-bound, in biomedicine are also attractive because their cost drawback could be less significant for high-value products. The review summarizes recent findings in immunomodulatory activities of trehalolipid biosurfactants from nonpathogenic Rhodococcus and related actinobacteria and compares their biomedical potential with well-known immunomodifying properties of trehalose dimycolates from Mycobacterium tuberculosis. Molecular mechanisms of trehalolipid interactions with immunocompetent cells are also discussed.

Regulation of interleukin-1β and interleukin-8 production by agonists of μ and δ opiate receptors in vitro

The studies reported here showed that β-endorphin at concentrations of 10−7–10−11 M increased interleukin-1β (IL-1β) production in unfractionated leukocyte suspensions both in the presence of 0.1 μg/ml lipopolysaccharide (LPS) and in cultures not stimulated with LPS. Interleukin-8 (IL-8) production by leukocytes was inhibited by β-endorphin at concentrations of 10−7 and 10−11 M in the presence of LPS. The stimulatory effect of β-endorphin on IL-1β production was not blocked by naloxone or naltrindole. Suppression of IL-8 production was blocked by naloxone and naltrindole. In the mononuclear cell and neutrophil fractions, β-endorphin and the δ agonist DADLE increased IL-1β synthesis in both the spontaneous and stimulated versions of the test, while β-endorphin and the δ agonist DADLE inhibited IL-8 production in the mononuclear cell and neutrophil fractions only in LPS-stimulated cultures. The μ agonist DAGO had no effect on IL-1β production by mononuclear cells or neutrophils, though it suppressed LPS-induced secretion of IL-8 by neutrophils.

Modulation of Cytokine Secretion and Oxidative Metabolism of Innate Immune Effectors by Rhodococcus Biosurfactant

The glycolipid biosurfactant complex from Rhodococcus ruber IEGM 231 had a stimulatory effect on the production of IL-12, IL-18, and reactive oxygen species by cells of the innate immunity. This effect depended on the composition of cell cultures and presence of LPS. It was primarily observed in non-stimulated cultures. The glycolipid biosurfactant complex had little effect on IL-10 secretion by monocytes and mononuclear cells.

Effect of Glycolipid Rhodococcus Biosurfactant on Secretory Activity of Neutrophils In Vitro

Glycolipid biosurfactant synthesized by nonpathogenic strain Rhodococcus ruber IEGM231 modulated the production of ROS and IL-8 by peripheral blood neutrophils in spontaneous and stimulated cultures. Secretion of IL-1β и TNF-α by neutrophils in the presence of biosurfactant changed insignifi cantly.

Role of β-endorphin in the regulation of proinflammatory cytokine production by peripheral blood monocytes in vitro

Abstractβ-Endorphin activated interleukin-1β production in the culture of unfractionated cells with lipopolysaccharide, but had no effect on the synthesis of tumor necrosis factor-α and interleukin-6. This peptide produced a slight stimulatory effect on spontaneous production of interleukin-1β by cultured leukocytes. Opioid receptor blockade with naloxone and naltrindole did not abolish the stimulatory effect of β-endorphin on interleukin-1β production. β-Endorphin did not modulate the synthesis of interleukin-1β, tumor necrosis factor-α, and interleukin-6 in a purified fraction of monocytes.

Effect of Opiate Receptors Blockade on Microbicidal Potential and Production of IL-1β, TNFα, and IL-10 by Peritoneal Macrophages under Stress Conditions

Rotation stress activated spontaneous and zymosan-induced ROS production. In animals receiving naloxone against the background of rotation stress, ROS production did not increase. Immobilization stress did not change the intensity of spontaneous and zymosan-induced ROS production, but inhibited stimulated ROS production against the background of naloxone treatment. Rotation produced a naloxone-independent inhibitory effect on spontaneous and stimulated IL-1β and TNFα production by macrophages and naloxone-dependent stimulating effect on spontaneous IL-10 production. Rotation stress did not modulate stimulated IL-10 production. In case of immobilization stress, decreased IL-1β and TNFα production was observed in mice exposed to stress under conditions of opiate receptors blockade; IL-10 production was not affected by immobilization stress. Both types of stress significantly increased plasma corticosterone levels, while naloxone had no effect on corticosterone production.

Effect of dynorphin A (1-17) on proliferation and IL-2, IL-4, IFN-γ production by peripheral blood mononuclears.

Dynorphin A (1-17) in concentrations of 10−8–10−9 M inhibits phytohemagglutinin (2.5 μg/ml)-induced proliferative response of mononuclear fraction lymphocytes. In mitogen-stimulated cultures, 10−8 M dynorphin A (1-17) stimulates the production of IL-4, inhibits the production of IL-2, and does not modify the production of IFN-γ. Nonselective κ-receptor antagonist naloxone and selective antagonist binaltorphimine hydrochloride abolish the inhibitory effects of both dynorphin A concentrations on the lymphocyte proliferative response. On the other hand, evaluation of the effect of κ-receptor blockade on the production of IL-2 and IL-4 showed that this effect depends on peptide concentration and antagonist type. Hence, the results attest to an important role of κ-receptors in modulation of functional activity of immune cells.

The role of monocytes in the effects of β-endorphin and selective agonists of μ-and δ-opiate receptors on the proliferative activity of peripheral blood lymphocytes

The effects of β-endorphin under the conditions of naloxone hydrochloride blockade of opiate receptors, as well as the effects of the selective agonists of μ-and δ-receptors DAGO and DADLE and the effects of melanocyte-potentiating factor (MPF), on the in vitro proliferative response of lymphocytes were studied. The dose-effect dependence indicated stimulating effects of β-endorphin, DAGO, and DADLE on the proliferative response in the presence of phytohemagglutinin (PHA). The tetrapeptide MPF, which is the C-terminal sequence of β-endorphin, had almost no effect on the proliferative activity of lymphocytes. β-Endorphin, naloxone, and the μ-and δ-receptor selective agonists enhanced the proliferative response of lymphocytes in an unfractionated cell culture, whereas β-endorphin, naloxone, and DAGO suppressed the proliferative activity of lymphocytes in the mononuclear fraction purified of monocytes. In both cases, the naloxone blockade of opiate receptors enhanced rather than eliminated the β-endorphin effect.