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Peptides from heptad repeat (HR1 and HR2) regions of gp41 are effective inhibitors of HIV-1 entry that block the fusion of viral and cellular membranes, but the generation of antibodies highly specific for these peptides is challenging. We have previously described a mouse hybridoma that recognizes MT-C34-related peptides derived from HR2. It was used for the selection of HIV-1-resistant CD4 lymphocytes engineered to express the MT-C34 peptide via a CRISPR/Cas9-mediated knock-in into the CXCR4 locus. In this study, we cloned variable domains of this antibody and generated a recombinant chimeric antibody (chAb) by combining it with the constant regions of the humanized antibody Trastuzumab. The new chAb displayed a high specificity and two-fold higher level of affinity than the parental mouse monoclonal antibody. In addition, chAb mediated up to 27–43% of the antibody-dependent cellular cytotoxicity towards cells expressing MT-C34 on their surface. The anti-MT-C34 chAb can be easily generated using plasmids available for the research community and can serve as a valuable tool for the detection, purification, and even subsequent elimination of HIV-1-resistant CD4 cells or CAR cells engineered to fight HIV-1 infection.

Lymphocyte phosphatase-associated phosphoprotein (LPAP) is a small transmembrane protein expressed exclusively in lymphocytes. LPAP is a component of a supramolecular complex composed of the phosphatase CD45, the co-receptor CD4, and the kinase Lck. In contrast to its immunologically important partners, the function of LPAP is unknown. We hypothesized that the biological role of LPAP may be determined by analyzing LPAP phosphorylation. In the present study, we identified LPAP phosphorylation sites by site-directed mutagenesis, phospho-specific antibodies, and protein immunoprecipitation coupled to mass spectrometry analysis. Our results confirmed previous reports that Ser-99, Ser-153, and Ser-163 are phosphorylated, as well as provided evidence for the phosphorylation of Ser-172. Using various SDS-PAGE techniques, we detected and quantified a set of LPAP phosphoforms that were assigned to a combination of particular phosphorylation events. The phosphorylation of LPAP appears to be a tightly regulated process. Our results support the model: following phorbol 12-myristate 13-acetate (PMA) or TCR/CD3 activation of T cells, LPAP is rapidly dephosphorylated at Ser-99 and Ser-172 and slowly phosphorylated at Ser-163. Ser-153 exhibited a high basal level of phosphorylation in both resting and activated cells. Therefore, we suggest that LPAP may function as a co-regulator of T-cell signaling.

Both SARS-CoV-2 infection and vaccination have previously been demonstrated to elicit robust, yet somewhat limited immunity against the evolving variants of SARS-CoV-2. Nevertheless, reports performing side-by-side comparison of immune responses following infection vs. vaccination have been relatively scarce. The aim of this study was to compare B-cell response to adenovirus-vectored vaccination in SARS-CoV-2-naive individuals with that observed in the COVID-19 convalescent patients six months after the first encounter with the viral antigens. We set out to use a single analytical platform and performed comprehensive analysis of serum levels of receptor binding domain (RBD)-specific and virus-neutralizing antibodies, frequencies of RBD-binding circulating memory B cells (MBCs), MBC-derived antibody-secreting cells, as well as RBD-specific and virus-neutralizing activity of MBC-derived antibodies after Gam-COVID-Vac (Sputnik V) vaccination and/or natural SARS-CoV-2 infection. Overall, natural immunity was superior to Gam-COVID-Vac vaccination. The levels of neutralizing MBC-derived antibodies in the convalescent patients turned out to be significantly higher than those found following vaccination. Our results suggest that after six months, SARS-CoV-2-specific MBC immunity is more robust in COVID-19 convalescent patients than in Gam-COVID-Vac recipients. Collectively, our data unambiguously indicate that natural immunity outperforms Gam-COVID-Vac-induced immunity six months following recovery/vaccination, which should inform healthcare and vaccination decisions.

Virus-like particles (VLPs) are an attractive vehicle for the delivery of Cas nuclease and guide RNA ribonucleoprotein complexes (RNPs). Most VLPs are produced by packaging SpCas9 and its sgRNA, which is expressed from the RNA polymerase III (Pol III)-transcribed U6 promoter. VLPs assemble in the cytoplasm, but U6-driven sgRNA is localized in the nucleus, which hinders the efficient formation and packaging of RNPs into VLPs. In this study, using the nuclease packaging mechanism of ‘NanoMEDIC’ VLPs, we produced VLPs with AsCas12a and exploited its ability to process pre-crRNA. This allowed us to direct crRNA in the cytoplasm as part of a Pol II-driven transcript where AsCas12a excised mature crRNA, thus boosting RNP incorporation into VLPs. CMV-driven crRNA increased Venus and CCR5 transgene knockout levels in 293 cells from 30% to 50–90% and raised the level of endogenous CXCR4 knockout in Jurkat T cells from 1% to 20%. Changing a single crRNA to an array of three or six identical crRNAs improved CXCR4 knockout rates by up to 60–70%. Compared to SpCas9-VLPs, the editing efficiencies of AsCas12a-VLPs were higher, regardless of promoter usage. Thus, we showed that AsCas12a and CMV-driven crRNA could be efficiently packaged into VLPs and mediate high levels of gene editing. AsCas12a-VLPs are a new and promising tool for the delivery of RNPs into mammalian cells that will allow efficient target genome editing and may be useful for gene therapy applications.

Lymphocyte phosphatase-associated phosphoprotein (LPAP) is a binding partner of the phosphatase CD45, but its function remains poorly understood. Its close interaction with CD45 suggests that LPAP may potentially regulate CD45, but direct biochemical evidence for this has not yet been obtained. We found that in the Jurkat lymphoid cells the levels of LPAP and CD45 proteins are interrelated and well correlated with each other. Knockout of LPAP leads to the decrease in the surface expression of CD45, while its overexpression, on the contrary, caused its increase. No such correlation was found in the non-lymphoid K562 cells. We hypothesize that LPAP regulates expression level of CD45 and thus can affect lymphocyte activation.

The CRISPR–Cas9 system has significantly advanced genome editing but remains constrained by its requirement for specific protospacer adjacent motifs (PAMs). To overcome this limitation, PAM-relaxed nucleases, including the novel near-PAMless chimeric SpRYc, have been developed. Here, we evaluated SpRYc editing activity across multiple experimental systems, including human HEK293 and CEM-R5 cells, as well as Drosophila melanogaster S2 cells and embryos. In HEK293 cells, SpRYc exhibited broad PAM compatibility, enabling editing at non-canonical PAMs, albeit with reduced and variable efficiency at canonical NGG sites compared to SpCas9. This context dependency was more pronounced in CEM-R5 T cells, where SpRYc activity at endogenous CXCR4 and B2M loci was largely restricted to NGG PAMs. In contrast, unlike SpCas9, SpRYc displayed negligible genome-editing activity in Drosophila embryos in vivo. Notably, the transcriptional activator dSpRYc-VPR showed robust activity in Drosophila S2 cells at both canonical and non-canonical PAMs. Reduced chromatin occupancy of dSpRYc-VPR suggests a balance between expanded PAM recognition and DNA-binding stability, providing a mechanistic explanation for context-dependent performance of SpRYc. Overall, our results highlight that expanded targeting flexibility comes at the cost of variable efficiency, underscoring the need for extensive locus- and context-specific validation of PAM-relaxed genome-editing tools.

The binding properties of synthetic and recombinant peptides derived from N-terminal part of ACE2, the main receptor for SARS-CoV-2, were evaluated. Additionally, the ability of these peptides to prevent virus entry in vitro was addressed using both pseudovirus particles decorated with the S protein, as well as through infection of Vero cells with live SARS-CoV-2 virus. Surprisingly, in spite of effective binding to S protein, all linear peptides of various lengths failed to neutralize the viral infection in vitro. However, the P1st peptide that was chemically “stapled” in order to stabilize its alpha-helical structure was able to interfere with virus entry into ACE2-expressing cells. Interestingly, this peptide also neutralized pseudovirus particles decorated with S protein derived from the Omicron BA.1 virus, in spite of variations in key amino acid residues contacting ACE2.

Rare earth metal nanoparticles, some of which are already widely used in medicine, are of growing interest in the modern scientific community. One of the promising rare earth metals for biomedical applications is cerium, specifically its oxide form, which is characterized by a higher level of stability and safety. According to a number of studies, cerium dioxide has a wide range of biological effects (regenerative, antimicrobial, antioxidant, antitumor), which justifies the interest of its potential application in medicine. However, these effects and their intensity vary significantly across a number of studies. Since cerium dioxide was used in these studies, it can be assumed that not only is the chemical formula important, but also the physicochemical parameters of the nanoparticles obtained, and consequently the methods of their synthesis and modification with the use of excipients. In this review, we considered the possibilities of using a number of excipients (polyacrylate, polyvinylpyrrolidone, dextran, hyaluronic acid, chitosan, polycarboxylic acids, lecithin, phosphatidylcholine) in the context of preserving the biological effects of cerium dioxide and its physicochemical properties, as well as the degree of study of these combinations from the point of view of the prospect of creating drugs based on it for biomedical applications.

Cutaneous regeneration remains a major challenge in biomedicine, prompting the exploration of novel therapeutic agents such as cerium oxide nanoparticles (CeO2 NPs, nanoceria). These nanoparticles exhibit multifaceted regenerative properties, including stimulation of metabolic and proliferative activity in keratinocytes, fibroblasts, and endothelial cells, potent antioxidant effects, immunomodulatory potential, and antimicrobial activity. Although numerous in vitro studies have characterized these properties, there is a critical need to evaluate nanoceria in more physiologically relevant in vivo settings, where dynamic biological conditions may significantly influence their efficacy. Furthermore, the therapeutic performance of CeO2 NPs is highly dependent on the synthesis methods and formulation components (excipients and co-administered active substances). A review of existing in vivo studies investigating nanoceria-based formulations for wound healing addresses this gap. The authors found 25 relevant studies published as of September 2025 in major scientific databases, including PubMed, Scopus, the Cochrane Library, which provided data on the effectiveness of using cerium oxide nanoparticles as components of medical devices or wound dressings in accelerating wound healing in animal models. This analysis synthesizes evidence on nanoparticle efficacy, formulation strategies, and observed biological outcomes across animal models. These findings indicate that nanoceria formulations can accelerate wound closure and modulate the key phases of tissue repair, although the outcomes vary with particle characteristics and delivery systems. While nanoceria hold considerable promise for clinical wound management, standardized reporting of synthesis protocols and rigorous comparative in vivo studies are essential to translate their potential into reliable therapeutic applications.

In recent years, the world scientific community has shown increasing interest in rare earth metals in general and their nanoparticles in particular. Medicine and pharmaceuticals are no exception in this matter. In this review, we have considered the main opportunities and potential applications of rare earth metal (gadolinium, europium, ytterbium, holmium, lutetium, dysprosium, erbium, terbium, thulium, scandium, yttrium, lanthanum, europium, neodymium, promethium, samarium, praseodymium, cerium) nanoparticles in biomedicine, with data ranging from single reports of effects found in vitro to numerous independent in vivo studies, as well as a number of challenges to their potential for wider application. The main areas of application of rare earth metals, including in the future, are diagnosis and treatment of malignant neoplasms, therapy of infections, as well as the use of antioxidant and regenerative properties of a number of nanoparticles. These applications are determined both by the properties of rare earth metal nanoparticles themselves and the need to search for new approaches to solve a number of urgent biomedical and public health problems. Oxide forms of lanthanides are most often used in biomedicine due to their greatest biocompatibility and nanoscale size, providing penetration through biological membranes. However, the existing contradictory or insufficient data on acute and chronic toxicity of lanthanides still make their widespread use difficult. There are various modification methods (addition of excipients, creation of nanocomposites, and changing the morphology of particles) that can reduce these effects. At the same time, despite the use of some representatives of lanthanides in clinical practice, further studies to establish the full range of pharmacological and toxic effects, as well as the search for approaches to modify nanoparticles remain relevant.