Immunologiya

Introduction. One of the aspects of inflammation control is the nervous and immune cooperation. Due to a wide range of activation receptors and mediators inherent in both systems, as well as anatomical colocalization with nerve fibers, mast cells (MC) are key intermediaries between these integrating systems and form bi-directional neuro-mastocytic functional units. The anti-inflammatory role of the vagus has been experimentally demonstrated. Its effects are mediated by the α7-nicotinic acetylcholine receptor but the question of cholinergic regulation of MC remains unclear.

The aim of the study was to evaluate the effect of acetylcholine (ACh) on MC secretory functions.

Material and methods. The source of MCs was mouse peritoneal exudate (PMC) cells. ACh has the dose-dependent effect on spontaneous and anti-IgE-induced degranulation of PTC which was evaluated by the level of histamine and β-hexosaminidase release in 5 and 15 min after ACh administration. To inhibit the binding of ACh to its α7-nicotonic receptor α-bungarotoxin (10^–6 M) was used.

Results. ACh caused degranulation of unstimulated PMCs. In 5 min after ACh adding (10^–5 M) into the cell cultures the maximum secretion-stimulating effect was observed (39 % for histamine and 47 % for β-hexosaminidase). In the contrary, after adding ACh to PTCs prestimulated by anti-IgE antibodies dose-depend reduction of secretion (-20–30 %) was observed. This inhibitory effect was canceled in the presence of α-bungarotoxin which suggests the involvement of the α7-nicotinic ACh receptor in signal transduction.

Conclusion. The ACh effect on MCs depends on the initial state of the system. In the case of unstimulated mastocytes ACh promotes their degranulation and secretion of preformed mediators. On the contrary, in the framework of the immune response ACh can inhibit the MC activation to prevent their massive degranulation.

Introduction. One of the promising directions in the creation of new antibacterial glycoconjugate vaccines is the synthesis and study of protective preparations with a built-in adjuvant (BA), which can act as an agonist of toll-like receptors (TLRs), localized on the surface of many immunocompetent cells, in particular, macrophages and dendritic cells. The development of an approach to the synthesis of model conjugated constructs based on bacterial dextran and detoxified lipopolysaccharide (d-LPS) opens up the possibility of obtaining effective preventive and therapeutic preparations containing polysaccharide fragments of bacterial nature.

Aim – to synthesize conjugates of bacterial dextran and d-LPS Shigella sonnei, where connection is carried out due to the terminal D-glucose residue of dextran and the amino groups of the O-specific polysaccharide d-LPS, and also to evaluate the level of specific antibody response to the synthesized conjugates in experiment on mice.

Material and methods. Fractions of S. sonnei, phase 1 d-LPS with high and low molecular weight were obtained according to previously described methods. Each stage of the synthesis of activated dextran derivatives and conjugates was carried out under reductive amination conditions in the presence of sodium cyanoborohydride: 1) introduction of adipine dihydrazide (ADH) to the terminal dextran D-glucose residue; 2) introduction of an active aldehyde group through the reaction of ADH-derived dextran with glyoxal (GO), and 3) conjugation of activated ADH-GO-dextran with d-LPS S. sonnei, phase 1. The immunogenicity of the resulting preparations was estimated by the production of specific IgG antibodies in mice in response to immunization with the resulting conjugates

Results. As a result of the reaction of activated ADH-GO-dextran with high and low molecular weight fractions of d-LPS from S. sonnei, phase 1, the corresponding conjugates were obtained in high yield. Their structure was confirmed using NMR and mass spectrometry. The effectiveness of using GO to create «bridge» structures in the synthesis of conjugated constructs has been demonstrated. A study of the level of serum specific IgG to dextran fragment of the resulting conjugates in the blood of double administrated mice showed formation of reliable immune response.

Conclusion. The possibility of creating immunogenic conjugates with a new type of built-in BA has been demonstrated. Model constructs have been obtained in which bacterial dextran is used as a «weak» immunogen, and d-LPS from S. sonnei, phase 1, is used as BA. It is assumed that within the framework of this scheme, immunogenic conjugates can be obtained, which may include O-specific polysaccharides isolated from LPS, bacterial CPS, their oligosaccharide fragments, as well as synthetic oligosaccharides.

Introduction. B-lymphocytes can play an important role in the regulation of immune processes during pregnancy, which may be significantly different at systemic level and in placenta due to multiple factors of cell microenvironment and pregnancy complications.

The aim of the study was to establish the character of differentiation of B-lymhocytes loca­lized in decidua comparing to that in peripheral blood in normal pregnancy and preeclampsia

Material and methods. The material for examination were samples of peripheral blood andleucocyte infiltrate of decidua (LID). 67 women and 21 placentas were examined in compa­rison group without hypertensive disorders during pregnancy and 100 women and 31 placentas in the group of women with preeclampsia (PE). The study was done by flow cytometry method. The level of naïve cells (CD27^–IgD⁺), memory cells (CD27⁺IgD^±), «nonswitched» (CD27⁺IgD⁺), «switched» (CD27⁺IgD^–) memory and plasma cells (CD20^–CD38⁺) in CD19⁺ В-lymphocyte population was assessed. The level of CD5⁺В1а cells, IL-10⁺ Breg (CD20⁺IL-10⁺), antigen presenting HLA-DR⁺ cells was assessed in CD20⁺ B-lymphocyte population.

Results. In the LID of placenta comparing with peripheral blood: 1) in the comparison group and in the PE group there was a lower level of Breg and «switched» memory B-cells; 2) in the comparison group the level of B1a cells and «nonswitched» memory B-cells was higher, but the content of naive B-cells was lower; 3) in the PE group there was a smaller fraction of the total population of memory B cells. In contrast to the comparison group, in LID with PE the level of CD20⁺-B-lymphocytes, B1a cells and naive B-cells was higher, and the amount of memory B-cells and «non-switched» memory B-cells was significantly lower. The duration of manifestation and the severity of PE were not associated with the nature of differentiation of decidual B-lymphocytes.

Conclusion. The character of B-lymphocyte differentiation is different at systemic level and in placenta in normal pregnancy and preeclampsia.

Introduction. According to current concepts, metastasis is the result of a complex multi-stage process determined by the interaction between metastatic cells, tumor microenvironment and homeostatic mechanisms. Surface receptors present on the cells of the tumor itself play a major role in the progression and metastasis of melanoma. First of all, this applies to toll-like receptors (TLRs). Among the TLRs expressed by malignant melanocytes, there is TLR4. This is one of the most important representatives of the TLRs family, high expression of which on tumor cells and cells of the tumor microenvironment in various types of cancer closely correlates with the onset of oncogenesis, tumor progression and drug resistance. On the other hand, there is data on the suppression of tumor growth after stimulation of melanoma cells expressing TLR4 with lipopolysaccharide (LPS). At the same time as shown in a number of studies, when culturing tumor cells in vitro with detoxified TLR agonists, the number of cells expressing TLR4 increases, which can have a significant impact on tumor progression and metastasis upon subsequent administration of these cells to experimental animals.

Along with TLR4, there are a number of other antigens (Ag) on the surface of melanoma cells, changes in the expression of which can have a significant impact on the ability of tumor cells to metastasize. These include the chemokine CXCR4 (CD184), integrins, the receptor for hyaluronic acid (CD44) and the tumor stem cell marker, the CD24 protein.

Aim – to study the in vitro effect of detoxified lipopolysaccharide (Ac3-S-LPS) Shigella sonnei, phase 1, on metastasis and expression by melanoma cells B16 TLR4, chemokine receptor CXCR4 (CD184), integrin avß5, receptor for hyaluronic acid (CD44), tumor stem cell marker (CD24) and PD-L1 (CD274) protein (the ligand of the programmed cell death receptor PD-1) and MHC I.

Material and methods. B16 melanoma cells were cultured with different concentrations of Ac3-S-LPS for 48 hours at 37 °C in a CO₂ incubator and after the end of cultivation were injected intravenously into C57Bl/6 mice. On the 21^st day after tumor cell inoculation, the animals were sacrificed and the number of lung metastases was counted. To determine the effect of Ac3-S-LPS on the expression of surface Ag chemokine CXCR4, hyaluronic acid receptor, tumor stem cell marker, MHC I and PD-L1 protein, the cells were cultured and then stained with monoclonal antibodies (Ab) conjugated with fluorescent dyes. The samples were analyzed on a flow cytometer. To assess the expression of TLR4 and integrin avß5, tumor cells after cultivation with Ac3-S-LPS were stained with primary recombinant polyclonal At to TLR4, then secondary At – anti-rabbit IgG (H+L) fragment F(ab')2 conjugated with Alexa Fluor 488 and analyzed under a fluorescent microscope.

Results. The obtained results indicate that culturing tumor cells with a TLR4 agonist (Ac3-S-LPS) reduces their metastatic potential, increases the number of cells expressing TLR4, reduces the number of cells carrying CD184, and increases the number of cells carrying a receptor for hyaluronic acid (CD44). At the same time, the number of cells expressing tumor stem cell marker (CD24) and integrin αvβ5 remained virtually unchanged. The presence of the CXCR4 receptor on tumor cells is of great importance for the formation of metastases in the lungs. The effect of culturing tumor cells with Ac3-S-LPS on the expression of CXCR4 on cells carrying CD44, CD24 and PD-L1 (CD274) was studied. It was found that culturing melanoma B16 cells with Ac3-S-LPS for 48 hours led to a decrease in the number of cells expressing CD184⁺/CD44⁺, and had virtually no effect on the number of cells carrying CD184⁺/CD24⁺ and CD184⁺/CD274⁺. At the same time, culturing tumor cells with Ac3-S-LPS led to an increase in the number of malignant melanocytes in the population expressing MHC I and PD-L1 proteins.

Conclusion. Cultivation of B16 melanoma cells with detoxified Shigella sonnei, phase 1, LPS leads to a decrease in the metastatic potential of tumor cells. This effect is due to a decrease in the number of cells carrying CXCR4 under the influence of Ac3-S-LPS. And although after cultivation with an agonist, the number of cells carrying CD44⁺ increases, which greatly facilitates the emigration of cells from primary tumor nodes, the absence of the CXCR4 receptor on them does not allow them to be localized in lung tissue.

Introduction. Over the last decade, technologies have emerged in cancer therapy that use T cells that have a genetically modified T cell receptor or have a chimeric T cell receptor that allows them to recognize various antigens. Some types of such cells have been shown to be highly effective in treating malignant neoplasms. The use of 3D-cultures to determine the mechanisms of action of such T cells provides additional insight into the action of transduced T cells when in contact with tumors in the form of 3D-cultures.

Aim of the study – determination of the phenotype and cytokine production of TCR-like CAR/CAR/TCR T cells upon contact with tumors in the form of 3D-cultures.

Material and methods. TCR-like CAR/CAR/TCR T cells were generated by transduction of healthy donor peripheral blood cells with γ-retroviral vectors. The phenotype of the transduced TCR-like CAR/CAR/TCR T cells was assessed by flow cytometry. 3D-cultures of the SK-MEL-37 melanoma tumor cell line were generated using the hanging drop method. Cytokine production in the culture of TCR-like CAR/CAR/TCR T cells and a 3D-spheroid of the SK-MEL-37 melanoma line was evaluated using multiplex analysis.

Results. Phenotype analysis showed that after transduction of TCR-like NY-ESO-1, TCR-like CAR MAGE-A4 and CAR GD2 specific T cells, dominant populations of CD4⁺ and CD8⁺ effector T cells are formed. Evaluation of cytokine production showed that in the conditioned medium from co-cultures of TCR-like CAR/CAR/TCR T cells and SK-MEL-37 3D-spheroid, a large number of antitumor cytokines are observed.

Conclusion. Transduction with γ-retroviral vectors targeting specific antigens leads to the formation of effector T cells, which, when co-cultured in 3D-cultures, produce a large number of antitumor cytokines, making the use of 3D-models promising for the development of clinical models of solid tumor therapy.

B cells are key mediators of humoral immunity and the second most important population of adaptive immune cells after T cells, playing a significant role in various conditions, including infections, allergies, autoimmune diseases, transplantation, and malignant tumors. B cells are considered as key players in modulating the immune response in cancer. Various B cell populations have been found in the tumor microenvironment, ranging from naive B cells to terminally differentiated plasma cells and memory B cells. They are capable of exhibiting both antitumor and protumor activity and can play an important role in immunotherapy of cancer. This article is a review of foreign and domestic literature devoted mainly to regulatory B cells and their role in the immune response to tumors. The review of literature devoted mainly to regulatory B cells and their role in the immune response to tumors.

Agonists of pattern-recognition receptors (PRR) cause stable epigenetic and metabolic alterations in innate immune cells resulting in long-lasting enhancement of responsiveness to secondary stimulation of the same or other PRRs. This altered responsiveness, termed trained immunity, may underlie non-specific protective effects of vaccines (heterologous protection). The COVID-19 pandemic offered great opportunities for testing the efficacy of trained immunity as an anti-infection defense strategy. However, despite promising preliminary data, randomized clinical trials (RCT) of BCG vaccine as a means to prevent COVID-19 in elderly people, persons with comorbidities and healthcare workers yielded mostly negative results. Lack of success of most RCT might have been caused by insufficiently intense vaccination schemes. Available laboratory data do not support a conclusion that BCG-induced heterologous protection against COVID-19 observed in some RCT is mediated by trained immunity. However, trained immunity may improve efficacy of specific anti-COVID-19 vaccines.

DOI: https://doi.org/10.33029/1816-2134-2025-46-1-86-142

DOI: https://doi.org/10.33029/1816-2134-2025-46-1-86-142

DOI: https://doi.org/10.33029/1816-2134-2025-46-1-86-142