Problems of creating antibody phage libraries and their solutions

Phage display has become an efficient, reliable and popular molecular technique for generating libraries encompassing millions or even billions of clones of divergent peptides or proteins. The method is based on the correspondence between phage genotype and phenotype, which ensures the presentation of recombinant proteins of known amino acid composition on the surface of phage particles. The use of affinity selection allows one to choose variants with affinity for different targets from phage libraries. The implementation of the antibody phage display technique has revolutionized the field of clinical immunology, both for developing tools to diagnose infectious diseases and for producing therapeutic agents. It has also become the basis for efficient and relatively inexpensive methods for studying protein-protein interactions, receptor binding sites, as well as epitope and mimotope identification. The antibody phage display technique involves a number of steps, and the final result depends on their successful implementation. The diversity, whether natural or obtained by combinatorial chemistry, is the basis of any library. The choice of molecular techniques is critical to ensure that this diversity is maintained during the phage library preparation step and during the transformation of E. coli cells. After a helper phage is added to the suspension of transformed E. coli cells, a bacteriophage library is formed, which is a working tool for performing the affinity selection procedure and searching for individual molecules. Despite the apparent simplicity of generating phage antibody libraries, a number of subtleties need to be taken into account. First, there are the features of phage vector preparation. Currently, a large number of phagemid vectors have been developed, and their selection is also of great importance. The key step is preparing competent E. coli cells and the technology of their transformation. The choice of a helper phage and the method used to generate it is also important. This article discusses the key challenges faced by researchers in constructing phage antibody libraries.

Modelling Innovation competence profiles: the empowering roles of self-monitoring and resilience

BACKGROUND

Innovation competence has been found to constitute distinct innovative abilities that must be analyzed together to get a more comprehensive picture of their effectiveness in various targeted groups. Drawn from the componential theory of creativity, such personal traits as individual resilience and self-monitoring play a critical role in developing innovation competence across students. This research aims to investigate the innovation competence profiles of students from various educational levels and study the role of individual resilience and self-monitoring in predicting the memberships of these profiles.

METHODS

A cross-sectional survey was conducted among university and college students, studying in a metropolitan area of the North-West region. The sampling scheme was stratified by the level of education and age. The questionnaire included items on the participants' demographics, including gender, age, and level of education, measures of innovative abilities, individual resilience, and self-monitoring. This study sought to create innovation competence profiles in the student population using latent profile analysis. Multinomial logistic regression was employed to identify the impact of individual resilience and self-monitoring on innovation competence profile membership.

RESULTS

A sample of 638 university and college students was analyzed. The latent profile analysis classified students into three different innovation competence profiles - strong, moderate, and weak - with college and female students being identified as the typical members of the weak profile. Individual resilience increases the odds of membership into the strong profile than to moderate and weak profiles. High self-monitors have higher chances of being profiled into the strong profile than the weak and moderate profiles compared to the low self-monitors.

CONCLUSIONS

Training investment aimed at boosting the innovative abilities of employees should consider the innovation competence profile of the beneficiaries to inform decisions about the appropriate level of intervention required. Likewise, educators could enrich their courses devoted to improving the innovative abilities of students with content that aims to improve their level of resilience accompanied by social support. Theoretical and practical implications are also discussed.

The Search for Single-Domain Antibodies Interacting with the Receptor-Binding Domain of SARS-CoV-2 Surface Protein

We performed a search for nanoantibodies that specifically interact with the receptor-binding domain (RBD) of the SARS-CoV-2 surface protein. The specificity of single-domain antibodies from the blood sera of a llama immunized with RBD of SARS-CoV-2 surface protein S (variant B.1.1.7 (Alpha)) was analyzed by ELISA. Recombinant trimers of the SARS-CoV-2 spike protein were used as antigens. In this work, a set of single-domain antibodies was obtained that specifically bind to the RBD of the SARS-CoV-2 virus.

SARS-CoV-2 RBD Conjugated to Polyglucin, Spermidine, and dsRNA Elicits a Strong Immune Response in Mice

Despite the rapid development and approval of several COVID vaccines based on the full-length spike protein, there is a need for safe, potent, and high-volume vaccines. Considering the predominance of the production of neutralizing antibodies targeting the receptor-binding domain (RBD) of S-protein after natural infection or vaccination, it makes sense to choose RBD as a vaccine immunogen. However, due to its small size, RBD exhibits relatively poor immunogenicity. Searching for novel adjuvants for RBD-based vaccine formulations is considered a good strategy for enhancing its immunogenicity. Herein, we assess the immunogenicity of severe acute respiratory syndrome coronavirus 2 RBD conjugated to a polyglucin:spermidine complex (PGS) and dsRNA (RBD-PGS + dsRNA) in a mouse model. BALB/c mice were immunized intramuscularly twice, with a 2-week interval, with 50 µg of RBD, RBD with Al(OH)₃, or conjugated RBD. A comparative analysis of serum RBD-specific IgG and neutralizing antibody titers showed that PGS, PGS + dsRNA, and Al(OH)₃ enhanced the specific humoral response in animals. There was no significant difference between the groups immunized with RBD-PGS + dsRNA and RBD with Al(OH)₃. Additionally, the study of the T-cell response in animals showed that, unlike adjuvants, the RBD-PGS + dsRNA conjugate stimulates the production of specific CD4+ and CD8+ T cells in animals.

Are Hamsters a Suitable Model for Evaluating the Immunogenicity of RBD-Based Anti-COVID-19 Subunit Vaccines?

Currently, SARS-CoV-2 spike receptor-binding-domain (RBD)-based vaccines are considered one of the most effective weapons against COVID-19. During the first step of assessing vaccine immunogenicity, a mouse model is often used. In this paper, we tested the use of five experimental animals (mice, hamsters, rabbits, ferrets, and chickens) for RBD immunogenicity assessments. The humoral immune response was evaluated by ELISA and virus-neutralization assays. The data obtained show hamsters to be the least suitable candidates for RBD immunogenicity testing and, hence, assessing the protective efficacy of RBD-based vaccines.

Immunogenic Properties of the DNA Construct Encoding the Receptor-Binding Domain of the SARS-CoV-2 Spike Protein

The development of preventive vaccines became the first order task in the COVID-19 pandemic caused by SARS-CoV-2. This paper reports the construction of the pVAX-RBD plasmid containing the Receptor-Binding Domain (RBD) of the S protein and a unique signal sequence 176 which promotes target protein secretion into the extracellular space thereby increasing the efficiency of humoral immune response activation. A polyglucine-spermidine conjugate (PGS) was used to deliver pVAX-RBD into the cells. The comparative immunogenicity study of the naked pVAX-RBD and pVAX-RBD enclosed in the PGS envelope showed that the latter was more efficient in inducing an immune response in the immunized mice. In particular, RBD-specific antibody titers were shown in ELISA to be no higher than 1 : 1000 in the animals from the pVAX-RBD group and 1 : 42 000, in the pVAX-RBD-PGS group. The pVAX-RBD‒PGS construct effectively induced cellular immune response. Using ELISpot, it has been demonstrated that splenocytes obtained from the immunized animals effectively produced INF-γ in response to stimulation with the S protein-derived peptide pool. The results suggest that the polyglucine-spermidine conjugate-enveloped pVAX-RBD construct may be considered as a promising DNA vaccine against COVID-19.

[Immunogenic Properties of the DNA Construct Encoding the Receptor-Binding Domain of the SARS-CoV-2 Spike Protein]

The development of preventive vaccines became the first order task in the COVID-19 pandemic caused by SARS-CoV-2. This paper reports the construction of the pVAX-RBD plasmid containing the Receptor-Binding Domain (RBD) of the S protein and a unique signal sequence 176 which promotes target protein secretion into the extracellular space thereby increasing the efficiency of humoral immune response activation. A polyglucine-spermidine conjugate (PGS) was used to deliver pVAX-RBD into the cells. The comparative immunogenicity study of the naked pVAX-RBD and pVAX-RBD enclosed in the PGS envelope showed that the latter was more efficient in inducing an immune response in the immunized mice. In particular, RBD-specific antibody titers were shown in ELISA to be no higher than 1 : 1000 in the animals from the pVAX-RBD group and 1 : 42000, in the pVAX-RBD-PGS group. The pVAX-RBD-PGS construct effectively induced cellular immune response. Using ELISpot, it has been demonstrated that splenocytes obtained from the immunized animals effectively produced INF-y in response to stimulation with the S protein-derived peptide pool. The results suggest that the polyglucine-spermidine conjugate-enveloped pVAX-RBD construct may be considered as a promising DNA vaccine against COVID-19.

The Perceived Impact of COVID-19 on Student Well-Being and the Mediating Role of the University Support: Evidence From France, Germany, Russia, and the UK

The rapid and unplanned change to teaching and learning in the online format brought by COVID-19 has likely impacted many, if not all, aspects of university students' lives worldwide. To contribute to the investigation of this change, this study focuses on the impact of the pandemic on student well-being, which has been found to be as important to student lifelong success as their academic achievement. Student well-being has been linked to their engagement and performance in curricular, co-curricular, and extracurricular activities, intrinsic motivation, satisfaction, meaning making, and mental health. The purpose of this study was to examine how student perceptions of their degree completion and future job prospects during the pandemic impact their well-being and what role university support plays in this relationship. We used the conservation of resources theory to frame our study and to develop five hypotheses that were later tested via structural equation modeling. Data were collected from 2,707 university students in France, Germany, Russia, and UK via an online survey. The results showed that university support provided by instructors and administration plays a mediating role in the relationship between the perceived impact of COVID-19 on degree completion and future job prospects and levels of student well-being. Student well-being is decreased by their concerns for their degree completion but not by their concerns for future job prospects. In turn, concerns for future job prospects affect student well-being over time. These results suggest that in a “new normal,” universities could increase student well-being by making support to student studies a priority, especially for undergraduates. Also, universities should be aware of the students' changing emotional responses to crisis and ensure visibility and accessibility of student support.

Prototype of a DNA Vaccine against Marburg Virus

The preparation and study of the biological properties of the pVAKS-GPVM DNA immunogen containing a gene encoding Marburgvirus glycoprotein are described. The specificity of blood serum antibodies of guinea pigs immunized with DNA immunogen was analyzed by ELISA. Inactivated viral preparation, recombinant glycoprotein (GP) obtained in the prokaryotic system and virus-like particles based on the recombinant vesicular stomatitis virus exhibiting Marburgvirus GP were used as the antigens. The neutralizing activity of antibodies of immunized animals was tested in vitro using a pseudovirus system. It was demonstrated that the developed immunogen administered to guinea pigs induced the production of specific antibodies that neutralize virus-like particles and Marburgvirus in cultured Vero cells.

Facial rejuvenation using Er:YAG laser equipped with a spatially modulated ablation module: A clinical, ultrasound, and histological evaluation

BACKGROUND

A plethora of noninvasive approaches has been developed in recent years for facial rejuvenation. Energy-based devices have been one of the most popular treatments for reversing and preventing signs of facial aging such as fine lines, wrinkles, ptosis, and photoaging.

AIMS

A new technology (RecoSMA) for skin rejuvenation based on acoustic-interference method using Er:YAG laser (2936 nm) equipped with a special module that targets both the dermis and the superficial musculoaponeurotic system (SMAS) was recently demonstrated to be safe and effective in facial rejuvenation.

PATIENT/METHODS

In this follow-up prospective study, the clinical effects of recoSMA treatment on skin structures and SMAS were evaluated with ultrasound and histological analysis, at 30 and 90 days posttreatment.

RESULTS

Treatment with recoSMA was shown to result in a significant increase in thickness of the epidermis, dermis, and SMAS layer, while levels of collagen I, III, and IV were shown to be elevated at 90 days posttreatment.

CONCLUSION

Collectively, data show that treatment with recoSMA laser has a profound biological effect in stimulating and reconstructing the elastin/collagen framework necessary for preventing facial aging.

[Nd:YAG laser goniopuncture as a mandatory adjuvant procedure after non-penetrating deep sclerectomy (long-term observation results)]

Today, Nd:YAG laser goniopuncture (LGP) is considered a mandatory non-penetrating deep sclerectomy adjuvant procedure. However, its indications and timing remain debatable.

PURPOSE

To evaluate the effect of Nd:YAG laser goniopuncture on the long-term hypotensive effectiveness of non-penetrating deep sclerectomy.

MATERIAL AND METHODS

The study included 114 patients after non-penetrating deep sclerectomy (NPDS). In the control group (n=58), Nd:YAG laser goniopuncture was performed within 3.4±1.9 (1.5-6.7) months, and in the main group (n=56) - within 1.12±0.08 (0.9-1.5) months after the surgery. Ultrasound biomicroscopy (UBM) was used to evaluate the semiotics of trabecular-Descemet's membrane (TDM), intrascleral canal (ISC) and filtering bleb. The follow-up period was 5 years.

RESULTS

According to UBM data, the thickness (0.10±0.009 mm) and density (50±6%) of TDM (p=0.0001) increased before LGP in the control group, the height of ISC decreased to 0.49±0.19 (0.20-0.40) (p=0.03), the height of UBM scan - to 1.49±0.05 (1.41-2.9) (p=0.0001); IOP (P₀) was 18.48±4.7 (11.2-22.9) mmHg (p=0.001). In the main group before LGP, TDM thickness was 0.08±0.006 mm, density was 40±5%, and IOP (P₀) was 15.7±4.1 (9.1-18.5) mm Hg. Complete hypotensive success was achieved in 83.6% of cases in the control group and 96.2% in the main group in 6 months; 68.07% and 92.59% in 12 months; 41.3% and 75.8% in 24 months; 15.25% and 48.93% in 36; 15% and 34.8% in 60 months after the surgery, respectively (p=0.0001, 95% confidence interval).

CONCLUSION

TDM is an additional level of retention of aqueous humor and plays key role in the formation of outflow pathways after NPDS. Performing LGP in the early postoperative period is an effective and safe adjuvant option, which excludes the influence of TDM on the formation of aqueous humor outflow pathways and significantly increases the long-term hypotensive efficacy of non-penetrating deep sclerectomy.

Novel method for facial rejuvenation using Er:YAG laser equipped with a spatially modulated ablation module: An open prospective uncontrolled cohort study

Facial aging is a complex biological process that affects the skin and superficial musculoaponeurotic system (SMAS). A new technology (RecoSMA) for skin rejuvenation based on acoustic-interference method using Er:YAG laser (2936 nm) equipped with a special module SMA that targets both the dermis and SMAS was evaluated in an open-label prospective cohort study of 100 female patients treated for facial rejuvenation. Measure of clinical improvement included investigator-rated clinical photography using the Modified Fitzpatrick Wrinkle Scale, and ultrasound measurements in the dermis a week, 30 days and six months post treatment. All patients completed the study and no complications were noted. Improvements in skin tone and texture were noted in all participants and significant decrease in wrinkle depth was demonstrated at the six-month follow-up that was confirmed by ultrasound skin measurements. Data presented herein confirm the safety and efficacy of RecoSMA treatment for facial rejuvenation.

A case of argyria of professional origin

The authors present data of an examination of a patient aged 70 suffering from a relatively rare dermatosis - argyria. The diagnosis was confirmed by professional case history, results of the histological examination of the skin and determination of the silver content in the biological environments and hair. The authors describe problems with diagnostics and treatment of the disease.

[Characteristics of the morphology and ultrastructure of the typhoid bacteria under limited and excess glucose conditions]

The authors present the results of the study of morphology and physico-biochemical indices of periodic and continuous population of typhoid bacilli under conditions of glucose limit and excess in the medium. Changes in the parameters of cell distribution by length proved to reflect the physiologico-biochemical processes in the population. The results of the study of the ultrastructure of typhoid bacilli of the "aerobic" and "anaerobic" population in continuous cultivation are presented. A possibility of application of morphological tests for the assessment of stability, homogeneity, and viability of the population is discussed.