[Ginkgolide B: mechanisms of neurobiological effects, prospects for use in the therapy of Alzheimer's disease]. / Ginkgolid B: mekhanizmy neirobiologicheskikh effektov, perspektivy primeneniya v terapii bolezni Al'tsgeimera.

The review presents an analysis of experimental data on the study of neurobiological effects of ginkgolide B, which may find application in the therapy of Alzheimer's disease (AD). Ginkgolide B is a diterpene trilactone isolated from the leaves of the relict woody plant Ginkgo biloba L., which has been used for thousands of years in traditional Chinese medicine as a neuroprotective agent. In recent years, this compound has attracted attention because of its wide range of neurobiological effects. The neuroprotective effect of ginkgolide B on brain neurons when exposed to various neurotoxins has been established. This compound has also been shown to effectively protect neurons from the effects of beta-amyloid. Studies have revealed the ability of ginkgolide B to reduce microglia activity and regulate neurotransmitter release. In vivo experiments have shown that this substance significantly increases the expression of brain-derived neurotrophic factor (BDNF) and improves cognitive functions, including memory and learning. It is concluded that ginkgolide B, apparently, may find application in the future as a multi-targeted agent of complex therapy of AD.

[BCG, muramylpeptides, trained immunity (part II): a low molecular weight alternative to multicomponent bacterial immunostimulants for prevention of respiratory infections during a pandemic].

During a pandemic, nonspecific immunoprophylaxis of SARS-CoV-2 infection and other acute respiratory infections (ARI), which can worsen the course of COVID-19, is increasingly in demand in addition to specific immunization. BCG vaccine appears to be one of the candidate immunostimulants in this regard. At the same time, other microbe-derived preparations capable of inducing a state of trained immunity deserve attention. BCG and other bacterial immunostimulatory agents containing a large number of biologically active subunits have long been considered as objects of search for promising pharmacological substances. The review analyzes the linkages between BCG, mycobacterial adjuvants, bacterial lysates, trained immunity, muramylpeptides (MPs) and NOD2 receptors in light of the choice of a low molecular weight alternative to multicomponent bacterial immunostimulants for ARI prevention during the COVID-19 pandemic. The search for key molecules by which bacteria stimulate innate and adaptive immune responses proceeds in a spiral. On different loops of this spiral, MPs have repeatedly reproduced the nonspecific effects of multicomponent bacterial adjuvants, vaccines and immunostimulants. MPs and peptidoglycans containing MPs determine the adjuvant properties of the cell walls of mycobacteria and their peptide-glycolipid fraction (wax D). MPs were able to replace Mycobacterium tuberculosis in complete Freunds adjuvant. MPs determine the NOD2-dependent ability of BCG to induce trained immunity. Probably, MPs provide NOD2-mediated long-term prophylactic action of bacterial lysates. All of the above has prompted revisiting the previously obtained evidence of the efficacy of glucosaminylmuramyl dipeptide (GMDP) as a NOD2 agonist in treatment/prevention of respiratory infections. We speculate here that MPs, in particular GMDP, at rational dosing regimens will be able to reproduce many aspects of the nonspecific effects of BCG and multicomponent bacterial immunostimulants in preventing ARI during the COVID-19 pandemic and in the post-pandemic period.

[Alzheimer's disease: experimental and clinical researches of Chinese herbal medicine neurobiological effects (a review).]

The analysis of experiments and clinical data about research of neurobiological effects of chinese herbal medicine, which is used by Alzheimer`s disease treatment, was presented in given overview. The rats with injection of Aß1-42 or Aß25-35 peptides, or ibotenic acid, or streptozotocin as well as the natural line of mice SAMP8 with the phenotype of accelerated aging and other were used as the experimental models of Alzheimer`s disease. Various neurobiological effects of various herbal decoctions in the cells of hippocampus were demonstrated - the inhibition of amyloid ß peptides aggregation, increasing of neurons quantity with normal morphology and decreasing of apoptotic cells, decreasing of inducible nitric oxide synthase (iNOS) production, decreasing of reactive expression level of RAGE and increasing reactive expression level of LRP-1, decreasing of tau protein phosphorylation at Thr231 and Ser422, inhibition of expression of GSK-3ß and CDK-5, decreasing of activation and inflammation of microglia, production of 15 types of N-glycans in the cerebral cortex layers, which are absent in experimental animals. The improvement of memorization and training abilities was established.

[BCG, muramylpeptides, trained immunity (part I): linkages in the light of the COVID-19 pandemic].

It has long been known that Bacillus CalmetteGurin (BCG) vaccine provides nonspecific protection against many non-mycobacterial infections, which has been discussed in the last decade through the prism of the concept of trained immunity. Within the framework of this concept, a persistent increase in resistance to various pathogens, which occurs after an infectious disease or exposure to certain microbial agents, is associated with epigenetic reprogramming of innate immune cells and their bone marrow progenitors. The COVID-19 pandemic has drawn attention of scientists and practitioners to BCG as an inducer of trained immunity. A number of epidemiological studies have suggested a negative association between the coverage of the population with BCG vaccination and the burden of SARS-CoV-2 infection. A series of independent clinical studies of the effectiveness of this vaccine in non-specific prevention of COVID-19 has been initiated in different countries. Recently, the key role of cytosolic NOD2 receptors in BCG-induced trained immunity has been proven. This actualizes the search for effective immunoactive preparations for prevention of respiratory infections in the pandemic among low molecular weight peptidoglycan fragments of the bacterial cell wall, muramylpeptides (MPs), which are known to be NOD2 agonists. The review highlights the proven and proposed linkages between BCG, MPs, NOD2 and trained immunity in the light of the COVID-19 pandemic. Analysis of the data presented indicates the prospects for preclinical and clinical studies of MPs as potential drugs for nonspecific prevention of SARS-CoV-2 infection and/or other respiratory infections in risk groups during the pandemic. First of all, attention should be paid to glucosaminylmuramyl dipeptide, approved for clinical use in Russia and a number of post-Soviet countries for the complex treatment and prevention of acute and recurrent respiratory infections.

[Use of probiotics and probiotic-based immunomodulators as adjuvant therapy for Helicobacter pylori eradication]. / Ispol'zovanie probiotikov i immunomoduliatorov na ikh osnove v kachestve ad''iuvantnoi terapii pri provedenii éradikatsii Helicobacter pylori.

At present, Helicobacter pylori (Нр) infection is the most common chronic bacterial infection in humans, the pathogen of which colonizes approximately 50% of the world's population. Hp eradication is required to control complications of Hp-related diseases (gastric and duodenal ulcers). Nevertheless, a number of investigations have demonstrated widespread antibacterial therapy inefficiency due to Hp antibiotic resistance and patient non-compliance with treatment regimens. Due to the growing need to elaborate alternative eradication regimens, some researchers have drawn their attention to probiotics and immunomodulators derived from Lactobacillus in particular for eradication therapy in Нp-positive patients to enhance the effect of antibacterial drugs. The review analyzes the results of 10 meta-analyses of randomized clinical trials with a similar design, which were published in 2007 to 2015, and other clinical trials assessing the role of probiotics and probiotic-based immunomodulators as an adjuvant therapy for Hp eradication. The results of the analysis have established that Lactobacillus strain-containing probiotics, both monocomponent probiotics and those as part of multicomponent ones, when used as an adjunct to anti-Hp therapy, significantly increase the level of Нp eradication by 8.1-20.0% (p<0.05; Level of Evidence, 1A; Recommendation Grade A). The use of N-acetylglucosaminyl-N-acetylmuramyl dipeptide (Licopid, a Lactobacillus bulgaricus-based immunomodulator) 0.001 and 0.01 g/day as an adjuvant to first-line triple anti-Hp therapy was shown to increase the level of Hp eradication by 7.1-8.9%. The intake of licopid 0.001 and 0.01 g/day during 7-day triple anti-Hp therapy results in the absence of recurrent Hp infection, as compared with 7- and 14-day treatment protocols without licopid, and leads to a significantly low incidence of Hp reinfection within 2-5 years after successful bacterial eradication, as compared with the 7-day protocol without adjuvant therapy with glucosaminylmuramyl dipeptide (p<0.05).

[A protein interaction network and cell signaling pathways activated by muramyl peptides].

Review is devoted to studying the interaction muramyl peptides with protein components of immune system cells. Systems analysis of published results may be useful to select not only the strategy to further explore the function of this class of glycopeptides, but their use in clinical practice.

[Comparison of adjuvant activities of glucosaminyl-muramyl dipeptide and of the gene coding for granulocyte-macrophage colony-stimulating factor in DNA immunization against herpes simplex virus].

Adjuvant activities of granulocyte-macrophage colony-stimulating factor (GM-CSF) and synthetic glucosaminyl-muramyl dipeptide (GMDP) were studied in immunization against type 1 herpes simplex virus (HSV1). Gene encoding the gD HSV1 protein (pDNAgD) was used as an immunogen. Gene encoding GM-CSF in pDNAGM-CSF plasmid, which was developed for eukaryotic expression, and GM-DP were used as immune response modulators. GMDP and plasmid DNA with inserted GM-CSF gene enhanced T-cell immune response to HSV1 after a single injection (pDNAGM-CSF) or 24 h before (GMDP) immunization with the gD HSV1 gene. Both adjuvants increased protective effect of DNA-immunization by a virus gene with 63 up to 100% after injection of two genes and up to 96% after the viral gene was inoculated 24 h after GMDP. These high effects indicate that further investigation of anti-HSV1 DNA-based vaccines used with genetic and peptide adjuvant is prospective.

Comparative study of macrophage response in mice after DNA immunization and infection with herpes simplex virus type 1.

Functional activity of macrophages and intensity of T cell immune response in mice were studied after intravaginal and intraperitoneal infection with herpes simplex virus type 1 and DNA vaccination in combination with adjuvant treatment (recombinant granulocyte-macrophage colony-stimulating factor and glucosaminylmuramyl dipeptide). DNA vaccination induced a virus-specific T cell immune response with no macrophagic inflammatory reaction. Infection with herpes simplex virus type 1 was accompanied by sustained inflammation, but not by the T cell immune response.

[New acellular pertussis vaccine, containing glucosaminylmuramyldipeptide]. / Sozdanie novoi beskletochnoi kokliushnoi vaktsiny, vkliuchaiushchei gliukozaminilmuramildipeptid.

As shown in this work, the synthetic immunomodulator glucosaminylmuramyldipeptide (GMDP) can be included into acellular pertussis vaccine (APV). The optimal doses of GMDP, ranging from 0.001 to 0.0001 microg, have been found. These doses enhance the protective activity of APV, especially its low-active doses. GMDP decrease the manifestations of toxic, anaphylactogenic and pyrogenic properties of APV, which may lead to the decrease of the antigenic load of APV on the body of the vaccines and thus to lessening the side-effects of vaccination. GMDP has been shown to considerably increase, in comparison with common pertussis vaccine and APV, the percentage of phagocytizing leukocytes by day 14. The immunization of mice with APV with and without GMDP in doses of 0.01 and 0.001 microg leads to a change in T-lymphocyte/B-lymphocyte ratio in the population of spleen lymphocytes.

[The use of immunomodulator likopid in the combined treatment pulmonary tuberculosis]. / Primenenie immunomoduliatora likopida v kompleksnom lechenii tuberkuleza legkikh.

Licopid is a synthetic analogue of a cell wall component of all bacteria. The monocytic macrophageal system is the main target of licopid's action. Addition of the immunomodulator to combined therapy for patients with pulmonary tuberculosis in order to enhance phagocytic activity exerted a marked clinical effect appeared as ceased bacterial isolation in 80% of the patients, a fall in the amount of purulent sputum, no symptoms of intoxication following 2-3 weeks, accelerated resolution of infiltrative changes. The positive clinical effect coincided with the immunological one manifested as increases in the absolute counts of CD3+CD4+ and CD3+CD8+ cells, in the absorptive and bactericidal functions of phagocytes. Such effects were not observed in patients receiving routine treatment. Licopid is recommended for supplementation to the combined treatment regimen for pulmonary tuberculosis.

Immune response modulation by recombinant peptides expressed in virus-like particles.

Aspergillus fumigatus, a ubiquitous fungus, is implicated in the pathogenesis of a number of clinically different allergic diseases in man, including allergic bronchopulmonary aspergillosis. Peptide-based immunotherapy may offer an alternative treatment strategy for the management of allergic disease. The objective of this study was to alter the allergen-specific immune response using dominant T cell epitopes of a major A. fumigatus allergen, Asp f2, expressed in yeast as virus-like particles (VLP). The T cell epitopes of Asp f2, recognized in mice with an H-2d background, were determined by producing T-cell hybridomas. Two dominant T cell epitopes, aa60--71 and aa235--249, were identified and expressed in a yeast VLP system. To induce tolerance VLP-peptides were injected subcutaneously into mice previously immunized with recombinant Asp f2. The T cell immune response was abrogated totally in 3 weeks following a single injection of VLP but was restored 2 months later following intranasal antigen exposure. T-cell depletion resulted in the reduction of 20-30% of all antigen-specific immunoglobulin classes. Thus, recombinant peptides expressed in the VLP system can be used successfully in the modulation of Asp f2-induced immune response in mice, although a single administration is not sufficient to maintain a state of tolerance for a long period of time.

Prevention of experimental septic shock by pretreatment of mice with muramyl peptides.

Muramyl peptides, immunostimulators with macrophage as a main target cell, are used for protecting mice from LPS-lethality (the experimental model of septic shock). Different protocols of pretreatment mice by muramyl peptides lead to opposite results. LPS and glycopeptides act synergistically in the induction of lethal shock, when mice receive peptides 1 day prior to lethal dose of LPS. However, extension of the period between the peptide and LPS injections to 6 days cancels the effect of synergism. Moreover, a 14-day interval between the same injections leads to protection of 70-90% animals from the toxic effect of LPS. Lipophilic analogs require 10-100 lower concentrations to protect the animals than the parent highly hydrophilic glycopeptides. Production of TNF, IL-1 and phagocytosis by macrophages was studied within the periods corresponding to "synergism" and LPS-resistance. High level of macrophage activity was observed during the "synergism" period. Low TNF production and reduced macrophage phagocyte activity corresponded to LPS-resistant state. These results partly explain the LPS-unresponsiveness in mice after their pretreatment by muramyl peptides.

Do T helpers 1 and 2 recognize different class II MHC molecules? Humoral and cellular immune responses to soluble allergen from Aspergillus fumigatus Asp f2.

Cellular signals leading to T helper (Th)1/Th2 shift are not well known. Here we demonstrate that Th1 possibly recognizes peptides presented by the IE molecule of MHC class II while Th2 is activated by the recognition of peptides presented by the IA molecule. BALB/c mice immunized with Asp f2 developed stable IA-restricted Th2 immune response to the 12th day after immunization, as analyzed by IL-2 production. On the contrary, early Th0 cells did not secrete IL-2 upon Asp f2 stimulation but did produce a high level of IL-2 if stimulated in the presence of anti-IA Abs. This effect of anti-IA Abs on early Th0 cells was both MHC IE and CD4(+) cell restricted. In vivo blocking of Asp f2 peptide presentation by the IA molecule led to the formation of antigen-specific cytotoxicity as demonstrated using immune splenocytes as effector cells and Asp f2 loaded P815 cells as targets.

Endogenous tumour necrosis factor-alpha sensitise melanoma cells to glucosaminylmuramyl dipeptide.

Flow cytometry was used to demonstrate that cultured human melanoma BRO cells expressed membrane-bound tumour necrosis factor-alpha (TNF-alpha) and were able to release TNF-alpha upon treatment with glucosaminylmuramyl dipeptide (GMDP). The released TNF-alpha was shown to prime melanoma cells, previously unable to respond to GMDP by increasing expression of melanoma-associated antigens, making them sensitive to GMDP treatment.

Synthesis and immunological evaluation of the conjugates composed from a muramyl peptide GMDP and tuftsin.

The conjugates of a muramyl dipeptide analog GMDP (N-acetylglucosaminyl beta 1-->4 N-acetylmuramyl-L-alanyl-D-isoglutamine) and tuftsin (Thr-Lys-Pro-Arg) were synthesized from unprotected GMDP by mixed anhydride procedure. The identity of the conjugates was confirmed by high resolution NMR and their immunomodulating properties were determined in various tests. It was found that the conjugate in which the GMDP carboxyl group forms an amide bond with the epsilon-amino group of tuftsin lysyl residue exceeds GMDP in all the activities determined. Synergism of GMDP and tuftsin was found in phagocytosis stimulation assay.