[Antiviral activity of immunomodulator Selank in experimental influenza infection].

The main objective of this study was to evaluate the antiviral properties of the glyproline Selank in both in vitro and in vivo against the influenza virus strain A/Aichi 2/68 (H3N2). The pronounced antiviral effect of the agent was detected in both systems. Selank added to the cell culture 24 hours before inoculation (a preventive use scheme) showed the highest efficiency, by completely suppressing viral reproduction. The in vivo studies also demonstrated that the highest survival of laboratory animals was observed when the agent was administered by the prevention scheme. The use of Selank in vivo induced the gene expression of interferon-alpha (IFN-alpha), without affecting that of interleukin (IL)-4, IL-10, or tumor necrosis factor-alpha (TNF-alpha). The findings suggest that the mechanism of the antiviral action of Selank may be due to its ability to modulate Th1/Th2/Treg cytokine equilibrium both directly and indirectly via the central nervous system. This is particularly promising if that the agent is synthesized on the basis of an endogenous peptide and that it has no negative effects is kept in mind.

[Immunomodulatory effects of selank in patients with anxiety-asthenic disorders].

The purpose of this article was to study the immunotropic effects of the new neurotrophic heptapeptide selank. The experiments in vitro revealed that the drug in concentration 10-7 M completely suppressed gene expression by peripheral blood IL-6 of patients with depression but not of the healthy controls. At the same time, the significant increase (p<0,05) of IL-6 concentration was observed in the cell culture of peripheral blood of patients in the presence of selank. The changes of the Th1/Th2 cytokine balance in vivo were found in the serum of patients with generalized anxiety disorder and neurasthenia who received Selank during 14 days. The dynamics of these changes had the significant inverse correlation dependence. The cytokine regulating effects revealed in the study suggest that selank can be used as a novel immunomodulator in patients with anxiety-asthenic disorders. Additionally, the adaptogenic properties of selank may be beneficial to its use in elderly people and people exposed to environmental stressors for the prevention of infectious diseases.

[Neuroendocrine immunomodulation].

Close interaction between the immune and nervous systems is well documented. The ability of immunocompetent cells to express receptors to neuroendocrine mediators as well as secrete many of them is proved. The current literature suggests that the hormones of the hypothalamic-pituitary-adrenal and the hypothalamic-pituitary-gonodal axes play the most significant role in the regulation of immune responsiveness. On the other hand, the immune system communicates with the CNS directly through the cytokines that are able to cross the blood-brain barrier, or directly via the nervus vagus, as well as via secondary messengers. Receptors to a number of cytokines have been found in the nervous tissue. Moreover, glial cells are able to secrete cytokines in the amount significant enough for at least autocrine action. In this article, the authors review the role of the "major" stress hormones such as cortisol, DHEA, growth hormone in the regulation of immune response, as well as neuro- and psychotropic properties of two major groups of cytokines that support cell-mediated (Type 1) and humoral (Type 2) immune reactions. This review emphasizes neuro-endocrine-immune interactions in response to infection both under laboratory and clinical conditions.

[The endogenous regulation of the cytokine disbalance in humans subjected to simulated spaceflight environment].

Confinement is one of the stress-inducing factors which humans face in such terrestrial environments as those in polar winter-over expeditions, submarines, and is inevitable in space flights. Confinement regime (CR) itself includes a number of stress factors (e.g. psychological compatibility between crew members, microbiological contamination etc.), which have been shown to alter human immunity. Two groups of total seven subjects spent 110 days in closed-habitat chamber as part of SFINCSS (Stimulation of Flight of International Crew on Space Station) study. Distribution of T-cell subsets, NK-, B-cells, and monocytes in whole blood was assessed. Secretion of type I (IL-2, IFN-gamma, TNF-beta) and type II (IL-4, IL-10) cytokines in the LPS/PHA activated whole blood cell culture was assessed. Significant alterations in type I / type II cytokine equilibrium were observed during and after confinement. The data show that stress factors associated with confinement may lead to disbalance between cell-mediated and humoral immune reactions.