Vol 89, No 5 (2024)

Chimeric Antigen Receptor (CAR) is a genetically engineered receptor that recognizes an antigen and subsequently activates a signaling cascade in a cell. Antigen recognition and signal transduction are carried out by different CAR domains derived from different proteins; thus, CAR has a mixed domain composition. Cytotoxic T cells expressing CAR recognizing tumor-associated antigens led to development of CAR-T, a novel approach in the therapy of malignant diseases. Despite the high efficacy of CAR-T in hematological malignancies, this approach has several disadvantages that could be overcame by using leucocytes from other groups as effector cells. Currently, many cells of both innate and adaptive immunity have been shown to express of CAR, leading to the development or enhancement of their cytotoxic properties. In this review, we discuss the peculiarities of CAR function in different types of immune cells will be covered. In particular, we focus on the results of pre-clinical and clinical research on the efficacy and safety of non-conventional CAR-expressing cells.

Induced pluripotent stem cells (iPSCs) due to their ability to differentiate into the desired cell type are a promising tool for solving the problems of transplantation medicine. In addition, the reprogramming technology makes it possible to obtain a personalized, i.e., patient-specific, cell product whose transplantation should not cause problems related to histocompatibility of transplanted tissues and organs. At the same time, inconsistent information about the main advantage of autologous iPSC derivatives – lack of immunogenecity – still casts doubt on the possibility of using such cells beyond immunosuppressive therapy protocols. This review is devoted to the immunogenic properties of syngeneic and autologous iPSCs and their derivatives, as well as to discussion of the reasons of dysregulation of their immune tolerance.

Tumor-associated macrophages (TAMs) are an important component of the tumor microenvironment (TME) and the most abundant population of immune cells infiltrating a tumor. TAMs can largely determine the direction of the anti-tumor immune response. TAMs can promote it or, conversely, contribute to the formation of an immunosuppressive TME that allows tumors to evade immune control. Through interactions with tumor cells or other cells in the microenvironment, and as a result of the action of anti-cancer therapy, macrophages can enter senescence. In this review, we have attempted to summarize the information available in the literature on the role of senescent macrophages in tumors. With the recent development of senolytic therapeutic strategies aimed at removing senescent cells from the organism. It seems important to discuss the functions of senescent macrophages and the potential role of senolytic drugs in reprogramming TAMs to enhance the anti-tumor immune response and improve the efficacy of cancer treatment.

Antigenic cartography is a tool for interpreting and visualizing antigenic differences between virus variants based on virus-neutralization data. This approach has been successfully used in influenza vaccine seed strain selection. With the emergence of SARS-CoV-2 variants escaping the vaccine-induced antibody response, adjusting the COVID-19 vaccines has become essential. This review provides information on antigenic differences between SARS-CoV-2 variants obtained by antigenic cartography. Moreover, it explores the potential of antigenic cartography-based methods, such as building antibody landscapes and neutralization breadth gain plots, for a quantitative assessment of the breadth of the antibody response. Understanding the antigenic differences of SARS-CoV-2 and the possibilities of the formed humoral immunity aids in the prompt modification of preventative vaccines against COVID-19.

Multiple sclerosis (MS) is a complex autoimmune disease of the central nervous system (CNS), characterized by myelin sheath destruction and compromised nerve signal transmission. Understanding the molecular mechanisms driving MS development is critical due to its early onset, chronic course, and therapeutic approaches based only on symptomatic treatment. Cytokines are known to play a pivotal role in the pathogenesis of MS, with interleukin-6 (IL-6) being one of the key mediators. This study investigates the contribution of IL-6 produced by microglia and dendritic cells to the development of experimental autoimmune encephalomyelitis (EAE), a widely used mouse model of MS. Mice with conditional inactivation of IL-6 in CX₃CR1+ cells, including microglia, or CD11c+ dendritic cells, displayed less severe symptoms as compared to their wild-type counterparts. Mice with microglial IL-6 deletion exhibited an elevated proportion of regulatory T cells and a reduced percentage of pathogenic IFNγ-producing CD4+ T cells, accompanied by a decrease in pro-inflammatory monocytes, in the CNS at the peak of EAE. At the same time, deletion of IL-6 from microglia resulted in an increase of CCR6+ T cells and GM-CSF-producing T cells. Conversely, mice with IL-6 deficiency in dendritic cells showed not only the previously described increase in the proportion of regulatory T cells and a decrease in the proportion of T_H17 cells, but also a reduction in the production of GM-CSF and IFNγ in secondary lymphoid organs. In summary, IL-6 functions during EAE depend on both the source and the localization of the immune response: microglial IL-6 exerts both pathogenic and protective functions specifically in the CNS, whereas dendritic cell-derived IL-6, in addition to being critically involved in the balance of regulatory T cells and T_H17 cells, may stimulate the production of cytokines associated with the pathogenetic functions of T cells.

Lymphocyte phosphatase-associated phosphoprotein (LPAP) is a protein of unknown function. Its close interaction with CD45 phosphatase suggests that LPAP may potentially regulate CD45, but direct biochemical evidence for this has not yet been obtained. We found that on Jurkat lymphoid cells the levels of LPAP and CD45 proteins are interrelated and well correlated with each other. Knockout of LPAP leads to a decrease, and its overexpression, on the contrary, causes an increase in the surface expression of CD45. No such correlation is found in non-lymphoid K562 cells. In the absence of LPAP, upon activation of Jurkat cells, a decrease in the expression of the activation marker CD69 was observed. This may be due to both direct and indirect effects of LPAP. We have hypothesized that LPAP is a regulator of the expression level of CD45 phosphatase.

The use of technology for the production of single-domain antibodies (NANOBODY® molecules, also referred to as nanoantibodies, nAb, or molecules based on other stable protein structures) and their derivatives to solve current problems in biomedicine is becoming increasingly popular. Indeed, the format of one small, highly soluble protein with a stable structure, fully functional in terms of specific recognition, is very convenient as a module for creating multivalent, bi-/oligo-specific genetically engineered targeting molecules and structures. The production of nAb in the periplasm of the E. coli bacterium is a very convenient and fairly universal way to obtain analytical quantities of nAb for the initial study of the properties of these molecules and the selection of the most promising nAb options. The situation is more complicated with the production of bi- and multivalent derivatives of initially selected nAbs under the same conditions. In this work, extended linker sequences (52 and 86 aa) between antigen-recognition modules in cloned expression constructs were developed and applied in order to increase the efficiency of production of bispecific nanoantibodies (bsNB) in the periplasm of E. coli bacteria. Three variants of model bsNBs described in this study were produced in the periplasm of bacteria and isolated in soluble form with preservation of the functionality of all protein domains. If earlier our attempts to produce bsNB in the periplasm with traditional linkers no longer than 30 aa were unsuccessful, the extended linkers used here provided a significantly more efficient production of bsNB, comparable in efficiency to the traditional production of the original monomeric nAbs. The use of highly elongated linkers can presumably be useful for increasing the efficiency of production of other bsNBs and similar molecules in the periplasm of E. coli bacteria.

G protein-coupled receptors (GPCRs) are transmembrane proteins that participate in most physiological processes and serve as key pharmacological targets. Recent advances in structural biology of GPCRs have enabled the development of drugs based on structure (Structure Based Drug Design, SBDD). SBDD utilizes information about the receptor– ligand complex to search for suitable compounds, expanding the chemical space of search without the need for experimental screening. In our review we include a description of Structural-base Virtual Screening (SBVS) of ligands to GPCRs and a description of methods for functional testing of selected potential drug compounds. We also discuss recent advances in the development of SBDD approaches applicable to GPCRs and highlight successful examples of their use.