Antibodies and antibody-based immunotherapeutics are the mainstays of cancer immunotherapy. Expanding the repertoire of cancer-specific and cancer-associated epitopes targetable with antibodies represents an important area of research. Phage display is a powerful approach allowing the use of diverse antibody libraries to be screened for binding to a wide range of targets. In this review, we summarize the basics of phage display technology and highlight the advances in anticancer antibody identification and modification via phage display platform. Finally, we describe phage display-derived anticancer monoclonal antibodies that have been approved to date or are in clinical development.

SARS-CoV-2 has a relatively high mutation rate, with the frequent emergence of new variants of concern (VOCs). Each subsequent variant is more difficult to neutralize by the sera of vaccinated individuals and convalescents. Some decrease in neutralizing activity against new SARS-CoV-2 variants has also been observed in patients vaccinated with Gam-COVID-Vac. In the present study, we analyzed the interplay between the history of a patient's repeated exposure to SARS-CoV-2 antigens and the breadth of neutralization activity. Our study includes four cohorts of patients: Gam-COVID-Vac booster vaccinated individuals (revaccinated, RV), twice-infected unvaccinated individuals (reinfected, RI), breakthrough infected (BI), and vaccinated convalescents (VC). We assessed S-protein-specific antibody levels and the ability of sera to neutralize lentiviral particles pseudotyped with Spike protein from the original Wuhan variant, as well as the Omicron variants BA.1 and BA.4/5. Individuals with hybrid immunity (BI and VC cohorts) exhibited significantly higher levels of virus-binding IgG and enhanced breadth of virus-neutralizing activity compared to individuals from either the revaccination or reinfection (RV and RI) cohorts. These findings suggest that a combination of infection and vaccination, regardless of the sequence, results in significantly higher levels of S-protein-specific IgG antibodies and the enhanced neutralization of SARS-CoV-2 variants, thereby underscoring the importance of hybrid immunity in the context of emerging viral variants.

Results of calculations of the electrodynamic characteristics of short five-gap accelerating cavities of the IH type are presented. The cavities are designed for a linear accelerator of protons and light ions with a charge-to-mass ratio A / Z ranging from 1 to 3.5. Developed at National Research Nuclear University MEPhI, this accelerator, which is designed as a source of charged particles with a beam energy of 7.5 MeV/nucleon, is intended for basic and applied research. The issues of the complex influence of the geometry of the drift tubes and the geometry of the drift tube support on the magnitude of the field strength on the surface of the resonators, the power losses in the walls of the resonators, and the distribution of the accelerating field on the axis are considered, taking into account the influence of the accuracy of segmenting in simulation.

The emergence of SARS-CoV-2 mutant variants has posed a significant challenge to both the prevention and treatment of COVID-19 with anti-coronaviral neutralizing antibodies. The latest viral variants demonstrate pronounced resistance to the vast majority of human monoclonal antibodies raised against the ancestral Wuhan variant. Less is known about the susceptibility of the evolved virus to camelid nanobodies developed at the start of the pandemic. In this study, we compared nanobody repertoires raised in the same llama after immunization with Wuhan’s RBD variant and after subsequent serial immunization with a variety of RBD variants, including that of SARS-CoV-1. We show that initial immunization induced highly potent nanobodies, which efficiently protected Syrian hamsters from infection with the ancestral Wuhan virus. These nanobodies, however, mostly lacked the activity against SARS-CoV-2 omicron-pseudotyped viruses. In contrast, serial immunization with different RBD variants resulted in the generation of nanobodies demonstrating a higher degree of somatic mutagenesis and a broad range of neutralization. Four nanobodies recognizing distinct epitopes were shown to potently neutralize a spectrum of omicron variants, including those of the XBB sublineage. Our data show that nanobodies broadly neutralizing SARS-CoV-2 variants may be readily induced by a serial variant RBD immunization.

The late stage of the COVID-19 pandemic is marked by the appearance of mutant variants of SARS-CoV-2 that can escape the immunity against the Wuhan virus. In this work, we report on the development of a panel of antiviral agents — single-domain antibodies that recognize independent epitopes of the SARS-CoV-2 S protein. Four antibodies from this panel neutralize a wide range of virus variants, including the most common ones at present: XBB.1.5 and XBB.1.16.

The rapid emergence of evasive SARS-CoV-2 variants is an ongoing challenge for COVID-19 vaccinology. Traditional virus neutralization tests provide detailed datasets of neutralization titers against the viral variants. Such datasets are difficult to interpret and do not immediately inform of the sufficiency of the breadth of the antibody response. Some of these issues could be tackled using the antigenic cartography approach. In this study, we created antigenic maps using neutralization titers of sera from donors who received the Sputnik V booster vaccine after primary Sputnik V vaccination and compared them with the antigenic maps based on serum neutralization titers of Comirnaty-boosted donors. A traditional analysis of neutralization titers against the WT (wild-type), Alpha, Beta, Delta, Omicron BA.1, and BA.4/BA.5 variants showed a significant booster humoral response after both homologous (Sputnik V) and heterologous (Comirnaty) revaccinations against all of the studied viral variants. However, despite this, a more in-depth analysis using antigenic cartography revealed that Omicron variants remain antigenically distant from the WT, which is indicative of the formation of insufficient levels of cross-neutralizing antibodies. The implications of these findings may be significant when developing a new vaccine regimen.

The article discusses the design of power coupling device for IH-type resonators for a new linear ion accelerator under development at the National Research Nuclear University MEPhI. The influence of mesh partitioning parameters on the accuracy of calculating the electric field intensity on the coupling loop surface is studied. The effect of the radius of curvature of the loop ends on the electric field intensity is also investigated. The electric field intensity values on the coupling loop surface are determined at the operating power level.

Over the past decade, CAR T cell therapy for patients with B cell malignancies has evolved from an experimental technique to a clinically feasible option. To date, four CAR T cell products specific for a B cell surface marker, CD19, have been approved by the FDA. Despite the spectacular rates of complete remission in r/r ALL and NHL patients, a significant proportion of patients still relapse, frequently with the CD19 low/negative tumor phenotype. To address this issue, additional B cell surface molecules such as CD20 were proposed as targets for CAR T cells. Here, we performed a side-by-side comparison of the activity of CD20-specific CAR T cells based on the antigen-recognition modules derived from the murine antibodies, 1F5 and Leu16, and from the human antibody, 2F2. Whereas CD20-specific CAR T cells differed from CD19-specific CAR T cells in terms of subpopulation composition and cytokine secretion, they displayed similar in vitro and in vivo potency.

This paper considers power supply issues arising in hybrid accelerating structures containing both standing and traveling wave sections in operation and power filling regimes and provides recommendations on power feeding design. Calculations of the 10 MeV electron linac efficiency in wide beam current range are presented. Magnetron stability issues are discussed.

In vitro and in vivo experiments often require construction of convenient cell instruments to reliably assess the specificity of the molecules or therapeutic approaches being tested against the protein target of interest. Using model isogenic cell lines that differ only in the expression of the target protein represents an ideal solution to this problem. Cloning and efficient delivery of genetic cassettes encoding such proteins, particularly the large ones, is typically challenging, much as the knock-out of the respective genes. To tackle this issue, we adapted a CRISPR/ Cas9-based SAM (Synergistic Activation Mediator) platform, and successfully established four model isogenic cell line pairs (U343, HeLa, HT-1080 и HEp-2) overexpressing human CD5.

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.

The development of effective vaccines against SARS-CoV-2 remains a global health priority. Despite extensive use, the effects of Sputnik V on B cell immunity need to be explored in detail. We performed comprehensive profiling of humoral and B cell responses in a cohort of vaccinated subjects (n = 22), and demonstrate that Sputnik vaccination results in robust B cell immunity. We show that B memory cell (MBC) and antibody responses to Sputnik V were heavily dependent on whether the vaccinee had a history of SARS-CoV-2 infection or not. 85 days after the first dose of the vaccine, ex vivo stimulated MBCs from the vast majority of Sputnik V vaccinees produced antibodies that robustly neutralized the Wuhan Spike-pseudotyped lentivirus. MBC-derived antibodies from all previously infected and some of the naïve vaccine recipients could also cross-neutralize Beta (B.1.351) variant of SARS-CoV-2. Virus-neutralizing activity of MBC-derived antibodies correlated well with that of the serum antibodies, suggesting the interplay between the MBC and long-lived plasma cell responses. Thus, our in-depth analysis of MBC responses in Sputnik V vaccinees complements traditional serological approaches and may provide important outlook into future B cell responses upon re-encounter with the emerging variants of SARS-CoV-2.

Immune evasion of SARS-CoV-2 undermines current strategies tocounteract the pandemic, with the efficacy of therapeutic virus-neutralizing monoclonal antibodies (nAbs) being affected the most. In this work, we asked whether two previously identified human cross-neutralizing nAbs, iB14 (class VH1-58) and iB20 (class VH3-53/66), are capable of neutralizing the recently emerged Omicron (BA.1) variant. Both nAbs were found to bind the Omicron RBD with a nanomolar affinity, yet they displayed contrasting functional features. When tested against Omicron, the neutralizing activity of iB14 was reduced 50-fold, whereas iB20 displayed a surprising increase in activity. Thus, iB20 is a unique representative of the VH3-53/66-class of nAbs in terms of breadth of neutralization, which establishes it as a candidate for COVID-19 therapy and prophylactics.

In an experimental study using the CRISPR/Cas9 system, "enhanced" NK cell lines with knockout of CISH, the gene for the CIS protein (a negative regulator of NK cytotoxicity), as well as two lines with a knocked-out β2-microglobulin gene, which provides membrane exposure of MHC class I, were obtained from two parental lines of human natural killers (YT wild type and YT-VAV1^(+) overexpressing the VAV1 cytotoxicity enhancing protein). The knockout efficiency was determined by real-time PCR as well as by flow cytometry with specific antibodies. The resulting CISH^(-/-) or B2M^(-/-) knockout lines were tested for cytotoxicity in primary monolayer cultures of human glioblastoma multiforme. The cytotoxicity of the lines was assessed using a cell analyzer that records the cell index based on cell impedance. YT-CISH^(-/-) has been shown to be significantly more effective than wild-type YT in eliminating primary glioblastoma cells in an in vitro cell monolayer experiment. The cytotoxicity of the YT-VAV1^(+)-CISH^(-/-) and YT-VAV1^(+)B2M^(-/-) lines against glioblastoma cells was the highest, but overall, it did not significantly differ from the initially increased cytotoxicity of the YT-VAV1^(+) line. The lines of NK-like cells obtained may serve as a prototype for the creation of "enhanced" allogeneic and autologous NK- and CAR-NK cells for the immunotherapy of glioblastoma multiforme.

Replication-incompetent adenoviral vectors have been extensively used as a platform for vaccine design, with at least four anti-COVID-19 vaccines authorized to date. These vaccines elicit neutralizing antibody responses directed against SARS-CoV-2 Spike protein and confer significant level of protection against SARS-CoV-2 infection. Immunization with adenovirus-vectored vaccines is known to be accompanied by the production of anti-vector antibodies, which may translate into reduced efficacy of booster or repeated rounds of revaccination. Here, we used blood samples from patients who received an adenovirus-based Gam-COVID-Vac vaccine to address the question of whether anti-vector antibodies may influence the magnitude of SARS-CoV-2-specific humoral response after booster vaccination. We observed that rAd26-based prime vaccination with Gam-COVID-Vac induced the development of Ad26-neutralizing antibodies, which persisted in circulation for at least 9 months. Our analysis further indicates that high pre-boost Ad26 neutralizing antibody titers do not appear to affect the humoral immunogenicity of the Gam-COVID-Vac boost. The titers of anti-SARS-CoV-2 RBD IgGs and antibodies, which neutralized both the wild type and the circulating variants of concern of SARS-CoV-2 such as Delta and Omicron, were independent of the pre-boost levels of Ad26-neutralizing antibodies. Thus, our results support the development of repeated immunization schedule with adenovirus-based COVID-19 vaccines.

In an experimental study using the CRISPR/Cas9 system, “enhanced” NK cell lines with knockout of CISH , the gene for the CIS protein (a negative regulator of NK cytotoxicity), as well as two lines with a knocked-out β2-microglobulin gene, which provides membrane exposure of MHC class I, were obtained from two parental lines of human natural killers (YT wild type and YT-VAV1 + overexpressing the VAV1 cytotoxicity enhancing protein). The knockout efficiency was determined by real-time PCR as well as by flow cytometry with specific antibodies. The resulting CISH –/– or B2M –/– knockout lines were tested for cytotoxicity in primary monolayer cultures of human glioblastoma multiforme. The cytotoxicity of the lines was assessed using a cell analyzer that records the cell index based on cell impedance. YT-CISH –/– has been shown to be significantly more effective than wild-type YT in eliminating primary glioblastoma cells in an in vitro cell monolayer experiment. The cytotoxicity of the YT-VAV1 + -CISH –/– and YT-VAV1 + B2M –/– lines against glioblastoma cells was the highest, but overall, it did not significantly differ from the initially increased cytotoxicity of the YT-VAV1 + line. The lines of NK-like cells obtained may serve as a prototype for the creation of “enhanced” allogeneic and autologous NK- and CAR-NK cells for the immunotherapy of glioblastoma multiforme.

The paper presents the results of the development of short five-gap IH-type accelerating structures with a fixed length of accelerating gaps, operated at 80 MHz and relative velocity of 0.06с and 0.1с. It has considered the issues of selecting the optimal length of accelerating gaps, the drift tube geometry, and the drift tube suspension system, taking into account limits on the magnitude of high-frequency losses in the cavity walls and the axis-field distribution, at which the field value in the extreme accelerating gaps is at least 50% of the field value in the central gaps.

Nowadays design of accelerating structures and traveling wave mode converter coupler cells in particular is almost excursively done using 2.5D and 3D codes based on finite elements method. These methods are extremely versatile and precise but require a lot of computational power. This paper describes mode converter coupler matching method using both finite element and equivalent circuit methods. Analytical calculation using equivalent circuit method provides an initial coupler parameter set for the finite element method calculations, accelerating further parameter conversion and reducing overall calculation time.

Background: The development of effective vaccines against SARS-CoV-2 remains a global health priority. Despite extensive use, several key immunological features of Sputnik V, an adenovirus-based two-component vaccine against SARS-CoV-2, need to be explored in detail. These include the effects of Sputnik V on B cell immunity and its ability to elicit antibody responses that are active against emerging neutralization-resistant SARS-CoV-2 variants. Methods: Our study included a cohort of 22 volunteers who received complete Sputnik V vaccination (two doses 21 days apart), 5 of who had a recent history of mild COVID-19, and 17 constituted a group of SARS-CoV-2 unexposed individuals. The frequencies of receptor-binding domain (RBD)-specific plasmablasts and B memory cells (MBCs), circulating and MBC-derived antibody secreting cells, virus binding, and virus-neutralizing activities of the sera, as well as samples of MBC-derived antibodies were analyzed using flow cytometry, ELISA, enzyme-linked immunosorbent spot (ELISpot), and pseudotyped virus neutralization assay at four time points spanning the period immediately before, during, and after vaccination. Findings: Longitudinal analysis of circulating serum antibodies showed that the anti-RBD IgG levels in naïve vaccine recipients substantially increased after the second vaccine dose (P<0.001), while in COVID-19-recovered individuals, this typically occurred after the first dose (P=0.0084). In recovered vaccine recipients, RBD-specific MBCs and SARS-CoV-2-specific MBC-derived antibody-secreting cells (ASCs) were already present prior to vaccination and remained stable until day 85. However, in naive vaccine recipients, RBD-specific MBCs and MBC-derived ASCs became detectable after the second dose and by day 85, they reached the levels observed in recovered vaccine recipients. In vitro stimulated MBCs from recovered individuals secreted a significant amount of anti-RBD IgG both on days 28 and 85. These antibodies demonstrated robust neutralization of the Wuhan Spike-pseudotyped lentivirus. In the naïve group, the level of anti-RBD IgG secretion was five- to six-fold reduced compared to that of the recovered group (P<0.001), and maximum virus neutralization (Wuhan spike) was achieved only on day 85. At this time point, the sera from both naïve and recovered vaccine recipients displayed neutralizing activities against the ancestral Wuhan and B.1.351 viruses, albeit the magnitude of neutralization against the mutant variant was 5.1–5.3-fold lower. Interpretation: B cell and antibody responses to Sputnik V were heavily dependent on whether the vaccinee had a history of SARS-CoV-2 infection or not. All the recovered and most naïve Sputnik V recipients displayed neutralizing antibody responses against the ancestral Wuhan and B.1.351 viruses. Plasmablast, RBD-specific MBCs, SARS-CoV-2-specific MBC-derived ASC responses, and humoral responses were more prominent in the recovered group of vaccinees than in the naïve subgroup, which may be indicative of their higher degree of long-term protection. Funding: This work was supported by the Russian Science Foundation (Project 21-15-00331) and the Russian Fund for Basic Research (20-04-60527).Declaration of Interest: None to declare. Ethical Approval: The study protocol was reviewed and approved by the Medical Ethical Committee of Institute of Immunology (#12-1, December 29, 2020).