Mecanismo y diseño de vacunas para el sars-cov-2, revisión narrativa / Mechanism and design of vaccines against sars-cov-2, narrative review / Mecanismo e desenho de vacinas para sars-cov-2, revisão narrativa

La infección por el virus SARS-CoV-2, conocida como COVID-19, ha causado alta morbilidad y mortalidad en el mundo. Después de haber descifrado el código genético del virus y haber desarrollado un gran trabajo investigativo en la creación de vacunas, con diversas estrategias de acción, se ha logrado disminuir la morbi mortalidad. Fue necesario acelerar el proceso de producción de vacunas, lo cual estuvo facilitado por el avanzado conocimiento científico en el campo de la genética y la virología, para brindar a la especie humana una protección eficaz y segura contra la agresiva y progresiva infección. Las vacunas se clasifican de acuerdo con su mecanismo de acción, existen vacunas basadas en vectores virales que no se replican, vacunas recombinantes, otras basadas en virus atenuados y virus inactivos, y (la gran novedad de la ciencia actual) las vacunas basadas en ARN mensajero y ADN. Estas últimas han demostrado una gran eficacia y seguridad en la prevención de la infección por el SARS-CoV-2, también han impactado de manera fuerte, por lo que han reducido la infección y la mortalidad en la población. En consecuencia, cada día que pasa desde que se inició el periodo de vacunación mundial, se evidencia una reducción en la curva de contagio y mortalidad por COVID-19.

The infection produced by the SARS-CoV-2 virus, known as COVID-19, has caused high morbidity and mortality across the world. After having deciphered the virus's genoma and carried out investigative endeavors that led to the creation of a variety of vaccines with different mechanisms of action, it has been possible to decrease the morbidity and mortality associated with the virus. It was necessary to accelerate the vaccine production process, which was facilitated by advanced scientific knowledge within the disciplines of genetics and virology, in order to provide the human species with a safe and effective form of protection against the aggressive and progressive infection. Vaccines are classified differently depending on their action mechanisms: there are some based on non-replicating viral vectors, recombinant vaccines, ones that are based on attenuated or inactivated viruses, and (the greatest novelty of current scientific developments) vaccines based on DNA and messenger RNA. The latter has demonstrated significant efficacy and safety in the prevention of the SARS-CoV-2 infection as observed in preliminary studies, and they have meaningfully impacted the population by reducing the rates of infection and mortality. As a result, decreased levels of spread of and mortality from COVID-19 have been evidenced across the globe following the beginning of the vaccine distribution period.

A infecção pelo vírus SARS-CoV-2, conhecido como COVID-19, tem causado elevada morbidade e mortalidade no mundo. Depois de ter decifrado o código genético do virus e de ter realizado um grande trabalho de investigação na criação de vacinas, com diversas estratégias de ação, a morbilidade e a mortalidade foram reduzidas. Foi necessário acelerar o processo de produção de vacinas, facilitado por conhecimentos científicos avançados no domínio da genética e da virologia, para proporcionar à espécie humana uma proteção eficaz e segura contra a infecção agressiva e progressiva. As vacinas são classificadas de acordo com seu mecanismo de ação, existem vacinas baseadas em vetores virais que não se replicam, vacinas recombinantes, outras baseadas em virus atenuados e vírus inativos, e (a grande novidade da ciência atual) vacinas baseadas em RNA mensageiro e ADN. Estas últimas demonstraram grande eficácia e segurança na prevenção da infecção por SARS-CoV-2, mas também tiveram um forte impacto, razão pela qual reduziram a infecção e a mortalidade na população. Consequentemente, a cada dia que passa desde o início do período global de vacinação, fica evidente uma redução na curva de contágio e mortalidade por COVID-19.

Recent advances in drug screening methods of SARS-CoV-2 spike protein / 药学学报

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a serious impact on global public health and the economy. SARS-CoV-2 infiltrates host cells via its surface spike protein, which binds to angiotensin-converting enzyme 2 on the host cell membrane. As a result, small molecules targeting spike protein have emerged as a hotspot in anti-SARS-CoV-2 drug research. Activity screening is an important step in seeking small molecule drugs. Therefore, this article aims to review the biological activity evaluation methods of small molecule inhibitors targeting SARS-CoV-2 spike protein, with the goal of laying the foundation for the discovery of new anti-SARS-CoV-2 drugs.

Discussion on results of national measurement capability comparison assessment for gross α and gross β radioactivity in water and calculation formulas for spike recovery / 中国辐射卫生

Objective To summarize and analyze the difficulties and key points in the measurement of gross α and gross β radioactivity in water based on the results of national measurement capability comparison assessment, and provide the basis and reference for the future work and the development of new local standards. Methods The research team participated in the comparison assessment for measurement of the gross radioactivity in water samples organized by National Institute for Radiological Protection, Chinese Center for Disease Control and Prevention. According to the comparison assessment results and the content in the national standard GB/T 5750.13—2023 (published draft), the steps of spike recovery involved during the measurement were analyzed and discussed. Two different formulas used for spike recovery calculation were analyzed for their impact on the final measurement results. Results When the spike recovery F(derived) derived from the formulas was used for result calculation, the spike recovery ranged as follows: gross α: 63.00%−84.60%, and gross β: 95.0%−99.1%; 3/6 of the comparison results were determined as excellent and 3/6 as pass as a whole (among them, 4 were excellent and 2 were pass for both single gross α assessment items and single gross β assessment items). When the spike recovery F from the GB/T 5750.13—2023 (published draft) was used for result calculation, the spike recovery ranged as follows: gross α: 39.69%−71.57%, and gross β: 90.25%−98.21%; 5/6 of the comparison results were determined as fail and 1/6 as pass (among them, 5 were fail and 1 was pass for single gross α assessment items; 5 were excellent and 1 was pass for single gross β assessment items). When two different formulas were used for spike recovery calculation, there was a significant difference in gross α radioactivity measurement (t = 4.27, P = 0.03 < 0.05), but there was no significant difference in gross β radioactivity measurement (t = 0.667, P = 0.524 > 0.05). Conclusion In the measurement of gross α and gross β radioactivity in water, appropriate reference to the spike recovery has a great influence on the measurement results. Therefore, quality control should be strengthened to further ensure the accuracy of measurement.

Encefalopatías epilépticas y del desarrollo. ¿Que hay de nuevo? / Developmental and epileptic encephalopathy. What is new?

Resumen Este artículo no tiene como objetivo el presentar una descripción detallada de cada una de las encefalopatías epilépticas y del desarrollo, sino más bien discutir cam bios recientes en la terminología y criterios diagnósticos de ciertas encefalopatías, en base a una revisión actua lizada de los últimos 10 años. Se analizan cambios importantes en definiciones de síndromes específicos y nuevos tratamientos que han demostrado eficacia en el manejo de crisis convulsivas en estos pacientes. En conclusión: Las nuevas terapias de modulación genética, contribuirán no solo a reducir la carga de crisis epilépticas, sino también a mejorar el pronóstico cognitivo, y por lo tanto la calidad de vida.

Abstract It is not the intend of this article to present a de tailed description of each developmental and epileptic encephalopathy, but to discuss recent changes in the terminology and diagnostic criteria of specific disorders, based on an updated review of the last 10 years. Important changes in the definitions of specific syn dromes and new treatments that have shown efficacy in the management of seizures in these patients are analyzed. In conclusion: New gene modulation therapy will likely improve not only seizure frequency, but also cog nitive outcome and therefore quality of life.

Research progress of angiotensin converting enzyme 2 co-expression in non-small cell lung cancer and SARS-CoV-2 / 中国胸心血管外科临床杂志

@#Since the first case of corona virus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at the end of 2019, the virus has spread rapidly around the world and has become a global public health problem. In the process of this virus epidemic, compared with the general population, cancer patients are considered to be highly susceptible people, especially the lung cancer patients. Some studies have shown that angiotensin converting enzyme 2 (ACE2) may be the pathway for SARS-CoV-2 to infect the host. At the same time, ACE2 is often abnormally expressed in non-small cell lung cancer. Therefore, understanding the respective mechanisms of ACE2 in COVID-19 and non-small cell lung cancer has extremely important reference value for the study of vaccines and therapeutic drugs, and also provides meaningful guidance for the protection of patients with lung cancer during the epidemic. This article reviews the possible invasive mechanism of ACE2 in SARS-CoV-2 and its abnormal expression in non-small cell lung cancer.

Overexpression of SARS-CoV-2 spike protein mediates growth inhibition in human retinal pigment epithelial cells / 中华眼底病杂志

Objective:To observe the inhibition of SARS-CoV-2 spike protein (S-protein) on the proliferation of human retinal pigment epithelium (RPE) cells.Methods:SARS-CoV-2 S-protein gene fragment expression plasmid (p3xflag-S) was constructed and transfected into human RPE, HEK293 cells. DNA sequencing was used for identification, and the expression of Flag-S was detected by Western blot. HEK293 cells were divided into the cells 1, 2, 3 and 4 and transfected with GFP11 plasmid and vector, GFP1-10 plasmid and vector, transfected with GFP11 and pCMV-HA-ACE2 plasmid, GFP1-10 and p3xflag-S plasmid. Cell 1 was co-cultured with cell 2 (control group 1), cell 2 with cell 3 (control group 2), cell 3 with cell 4 (observation group), and cell 1 mixed with cells 2, 3 and 4 (control group 3). Bright-field microscopy and fluorescence microscopy were used to observe cell fusion. RPE cells were divided into control group and overexpression S-protein group. The cell cycle was detected by flow cytometry; the cell proliferation level was detected by Counting Kit 8 (CCK-8); and the S-protein expression level in RPE cells was detected by Western blot. The Student’s t-test was performed for comparison between groups. Results:DNA sequence assay showed that S-protein cDNA was fused with flag-tagged protein. Western blot assay showed that S-protein-related expression was elevated in transfected HEK293 cells compared with untransfected p3xflag-S cells. Large, multinucleated fused cell clusters were visible under bright-field microscopy; multiple nuclear with distinct green fluorescence were visible in the fused cells under fluorescence microscopy. Western blot assay showed elevated S-protein-related expression in transfected p3xflag-S plasmid RPE cells compared to untransfected p3xflag-S plasmid RPE cells. CCK-8 results showed that the proliferative capacity of RPE cells in the S-protein overexpression group was significantly reduced compared with the control group, with statistically significant differences ( t=22.70, 16.75, 23.38; P<0.000 1). The results of flow cytometry showed that the G1 phase cells in the control and overexpression S-protein groups were 41.1 % and 67.0%, respectively; compared with the control group, the G1 phase cells in the overexpression S-protein group were significantly higher, and the difference was statistically significant ( t=4.76, P=0.018). The apoptosis rate was significantly increased in the S-protein overexpression group compared with the control group, and the difference was statistically significant ( t=4.91, P=0.008). Conclusion:Overexpression of the SARS-CoV-2 spike protein reduced the proliferation of human RPE cells.

Characteristics of whole genome analysis of severe acute respiratory syndrome coronavirus 2 during different epidemic periods in Wuxi City / 中华传染病杂志

Objective:To understand the genome sequence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and spike protein variations during different epidemic periods in Wuxi City.Methods:Nucleic acid was extracted from the nasopharyngeal swab samples of six local cases of coronavirus disease 2019 (COVID-19) (from January to February, 2020) and 13 imported cases of COVID-19 (from March to September, 2021) in Wuxi City, and the whole genome was amplified to construct the sequencing library. The second-generation sequencer was used for sequencing. The CLC Genomics Workbench (21 version) software was used to analyze the offline data with NC_045512.2 as the reference strain, and MEGA 7.0 software was used to construct the phylogenetic tree.Identification of type was conducted by Nextstrain typing method and phylogenetic assignment of named global outbreak lineages (Pangolin) typing method.Results:There were five subtypes in Nextstrain and seven subtypes in Pangolin of the nineteen patients with COVID-19. Compared with NC_045512.2, the median nucleotide mutation sites were 29 (range 0 to 42) and amino acid mutation sites were 20 (range 0 to 34). The six local and 13 imported cases had no common nucleotide mutation sites and were in different evolutionary branches. The sequences of the six local cases were highly homologous with the reference strain sequences (NC_045512.2) at the early stage of the pandemic, and the evolutionary distance was close to that of the reference strain. The 13 imported cases were obviously divided into three evolutionary branches (Alpha, Beta, Delta variant).The four Beta variants shared eight amino acid mutation sites in spike protein, and the two Alpha variants shared eight amino acid mutation sites in spike protein, and the seven Delta variants shared five amino acid mutation sites in spike protein.Conclusions:New mutations of SARS-CoV-2 are constantly emerging during the epidemic. The increase of the nucleotide sites number may result in the change of spike protein amino acid. Therefore, the whole-genome sequencing analysis plays an important role in the accurate tracing of epidemic origin and adjustment of prevention and control measures.

Factors associated with poor short-term pharmacotherapy response in self-limited epilepsy with centrotemporal spikes / 中华实用儿科临床杂志

Objective:To explore risk factors for clinical onset in children with uncontrolled self-limited epilepsy with centrotemporal spikes (SeLECTS) managed by 2 anti-seizure medications (ASMs).Methods:A total of 112 children with SeLECTS who were diagnosed at the Department of Pediatric Neurology of the Third Affiliated Hospital of Zhengzhou University from January 2018 to May 2021 were retrospectively reviewed.All of them were treated with conventional ASMs, and regularly followed up for 1-2 years.Types of therapeutic drugs, clinical seizure control status, presence of new seizure forms, electroencephalogram (EEG) were reviewed at follow-up visits.According to whether the seizures were controlled after the use of no more than 2 ASMs, patients were divided into poor response group (43 cases) and good response group (69 cases), and their clinical data and EEG characteristics were compared.Multivariate Logistic regression analysis was used to explore the risk factors for seizures that were uncontrolled by 2 ASMs. Results:There were significant differences in the age of onset ( χ2=8.919, P=0.003), seizure form ( χ2=4.218, P=0.040), seizure frequency ( Z=-7.664, P<0.001), EEG background slowing ( χ2=10.284, P=0.001), emergence of electrical status epilepticus during slow-wave sleep (ESES)( χ2=11.921, P=0.001), discharge generalization ( χ2=25.377, P<0.001), and presence of epileptic encephalopathy with spike-and-wave activation in sleep (EE-SWAS)( χ2=54.334, P<0.001) between groups.Multivariate Logistic regression analysis showed that seizure frequency ( P<0.001, OR=0.086, 95% CI: 0.022-0.329), discharge generalization ( P=0.006, OR=9.942, 95% CI: 1.918-51.527) and EEG background slowing ( P=0.041, OR=6.648, 95% CI: 1.077-41.038) were the 3 main risk factors associated with poor response to short-term medications of ASMs. Conclusions:Seizures are easily controlled in most SeLECTS patients medicated with ASMs with a favorable prognosis.Seizure frequency, discharge generalization and EEG background slowing are risk factors for the poor response to short-term pharmacotherapy in children with SeLECTS.

Design of a multi-epitope subunit vaccine candidate for chikungunya virus using computational methodology

@#Chikungunya virus (CHIKV) is a neglected tropical pathogen that causes fever and long-lasting severe arthralgia. Despite its high morbidity, there is still no licensed specific therapeutic option for it. This study proposes a multi-epitope subunit vaccine candidate for CHIKV, designed using computational methods. It was based on the E2 spike glycoprotein in CHIKV, from which T- and B-cell epitopes were predicted and then refined. The pan HLA DR-binding epitope (PADRE) was added to this refined construct, then simulated compared with the native protein, where it was predicted to elicit more than twice the number of antibody titers. Thus, this construct is potentially effective against CHIKV, which further experimentation using live models would be able to verify. This study also demonstrates the feasibility of using rational tools in the future to further optimize vaccine design.

Immunogenicity of mucosal COVID-19 vaccine candidates based on the highly attenuated vesicular stomatitis virus vector (VSVMT) in golden syrian hamster

COVID-19 is caused by coronavirus SARS-CoV-2. Current systemic vaccines generally provide limited protection against viral replication and shedding within the airway. Recombinant VSV (rVSV) is an effective vector which inducing potent and comprehensive immunities. Currently, there are two clinical trials investigating COVID-19 vaccines based on VSV vectors. These vaccines were developed with spike protein of WA1 which administrated intramuscularly. Although intranasal route is ideal for activating mucosal immunity with VSV vector, safety is of concern. Thus, a highly attenuated rVSV with three amino acids mutations in matrix protein (VSVMT) was developed to construct safe mucosal vaccines against multiple SARS-CoV-2 variants of concern. It demonstrated that spike protein mutant lacking 21 amino acids in its cytoplasmic domain could rescue rVSV efficiently. VSVMT indicated improved safeness compared with wild-type VSV as the vector encoding SARS-CoV-2 spike protein. With a single-dosed intranasal inoculation of rVSVΔGMT-SΔ21, potent SARS-CoV-2 specific neutralization antibodies could be stimulated in animals, particularly in term of mucosal and cellular immunity. Strikingly, the chimeric VSV encoding SΔ21 of Delta-variant can induce more potent immune responses compared with those encoding SΔ21 of Omicron- or WA1-strain. VSVMT is a promising platform to develop a mucosal vaccine for countering COVID-19.

Screening and identification of single-chain fragment variable against the receptor-binding domain of spike protein of SARS-CoV-2 / 中国生物制品学杂志

@#Objective To construct a single-chain fragment variable(scFv)phage display library against receptor-binding domain(RBD)of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)spike protein(S)to screen specific scFv and identify the function.Methods m RNA was extracted from spleen cells of mice immunized with RBD protein and reversely transcribed into c DNA,with which as template,genes of the hight chain fragment of variable(VH)and light chain fragment of variable(VL)of scFv were amplified and then assembled into scFv gene fragment through splicing overlap extension PCR(SOE-PCR).The scFv gene fragment was inserted to phage vector to construct scFv phage display library.After four rounds of biopanning,the scFv gene with strong binding ability to RBD was screened and expressed recombinantly,purified and identified for biological activity.Results The constructed scFv phage library showed a titer of 6.0×10(11)pfu/m L.After four rounds of biopanning,four scFv strains with strong binding to RBD were selected,namely scFv11,scFv12,scFv25and scFv28.scFv was mainly expressed in the form of inclusion body with a relative molecular mass of about 27 000,a concentration of 2.4 mg/m L and a purity of about 90%,which bound specifically to mouse monoclonal antibody against His labeled by HRP after purification.All four scFv strains bound specifically to RBD recombinant protein,among which the other 3 scFv strains bound to the S protein of wild type and multiple mutant strains except scFv28.All four strains showed dose-dependent interaction with RBD,with affinity dynamic fitting dissociation constants(K_Ds)8.9,5.92,10.67and 2.36 nmol/L,and steady-state fitting dissociation constants(K_Ds)of 5.3,6.5,8.7 and 5.8 nmol/L,respectively.scFv11,scFv12 and scFv25 simultaneously identified three independent RBD polypeptides,including RBD2(S(11)pfu/m L.After four rounds of biopanning,four scFv strains with strong binding to RBD were selected,namely scFv11,scFv12,scFv25and scFv28.scFv was mainly expressed in the form of inclusion body with a relative molecular mass of about 27 000,a concentration of 2.4 mg/m L and a purity of about 90%,which bound specifically to mouse monoclonal antibody against His labeled by HRP after purification.All four scFv strains bound specifically to RBD recombinant protein,among which the other 3 scFv strains bound to the S protein of wild type and multiple mutant strains except scFv28.All four strains showed dose-dependent interaction with RBD,with affinity dynamic fitting dissociation constants(K_Ds)8.9,5.92,10.67and 2.36 nmol/L,and steady-state fitting dissociation constants(K_Ds)of 5.3,6.5,8.7 and 5.8 nmol/L,respectively.scFv11,scFv12 and scFv25 simultaneously identified three independent RBD polypeptides,including RBD2(S(334～353)),RBD9(S(334～353)),RBD9(S(439～458))and RBD13(S(439～458))and RBD13(S(499～518)).Homologous model of scFv constructed by online server SWISS-MODEL showed a good quality and was used for molecular docking.The interface at which scFv11 interacted with RBD only partially coincided with the interaction interface of human angiotensin converting enzyme 2(ACE2)and RBD,and the interaction interfaces of scFv12 and scFv25 with RBD were quite different from that of ACE2.Conclusion In this study,scFv specifically bound to SARS-Co V-2 RBD was screened and prepared through constructing scFv phage library against SARS-CoV-2 RBD,which provided experimental basis for further development of anti-SARS-CoV-2 drugs and detection reagents.

Highly Sensitive Poly-N-isopropylacrylamide Microgel-based Electrochemical Biosensor for the Detection of SARS-COV-2 Spike Protein / 生物医学与环境科学（英文）

OBJECTIVE@#Late 2019 witnessed the outbreak and widespread transmission of coronavirus disease 2019 (COVID-19), a new, highly contagious disease caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Consequently, considerable attention has been paid to the development of new diagnostic tools for the early detection of SARS-CoV-2.@*METHODS@#In this study, a new poly-N-isopropylacrylamide microgel-based electrochemical sensor was explored to detect the SARS-CoV-2 spike protein (S protein) in human saliva. The microgel was composed of a copolymer of N-isopropylacrylamide and acrylic acid, and gold nanoparticles were encapsulated within the microgel through facile and economical fabrication. The electrochemical performance of the sensor was evaluated through differential pulse voltammetry.@*RESULTS@#Under optimal experimental conditions, the linear range of the sensor was 10 -13-10 -9 mg/mL, whereas the detection limit was 9.55 fg/mL. Furthermore, the S protein was instilled in artificial saliva as the infected human saliva model, and the sensing platform showed satisfactory detection capability.@*CONCLUSION@#The sensing platform exhibited excellent specificity and sensitivity in detecting spike protein, indicating its potential application for the time-saving and inexpensive detection of SARS-CoV-2.

SARS-CoV-2 spike host cell surface exposure promoted by a COPI sorting inhibitor

Via an insufficient coat protein complex I (COPI) retrieval signal, the majority of SARS-CoV-2 spike (S) is resident in host early secretory organelles and a tiny amount is leaked out in cell surface. Only surface-exposed S can be recognized by B cell receptor (BCR) or anti-S therapeutic monoclonal antibodies (mAbs) that is the trigger step for B cell activation after S mRNA vaccination or infected cell clearance by S mAbs. Now, a drug strategy to promote S host surface exposure is absent. Here, we first combined structural and biochemical analysis to characterize S COPI sorting signals. A potent S COPI sorting inhibitor was then invented, evidently capable of promoting S surface exposure and facilitating infected cell clearance by S antibody-dependent cellular cytotoxicity (ADCC). Importantly, with the inhibitor as a probe, we revealed Omicron BA.1 S is less cell surface exposed than prototypes because of a constellation of S folding mutations, possibly corresponding to its ER chaperone association. Our findings not only suggest COPI is a druggable target against COVID-19, but also highlight SARS-CoV-2 evolution mechanism driven by S folding and trafficking mutations.

A comparative study of antibody response, virus neutralization efficiency & metabolites in SARS-CoV-2-infected adults & children

Background & objectives: COVID-19 has been a global pandemic since early 2020. It has diverse clinical manifestations, but consistent immunological and metabolic correlates of disease severity and protection are not clear. This study was undertaken to compare seropositivity rate, antibody levels against nucleocapsid and spike proteins, virus neutralization and metabolites between adult and child COVID-19 patients. Methods: Plasma samples from naïve control (n=14) and reverse transcription (RT)-PCR positive COVID-19 participants (n=132) were tested for reactivity with nucleocapsid and spike proteins by ELISA, neutralization of SARS-CoV-2 infectivity in Vero cells and metabolites by 1H nuclear magnetic resonance (NMR) spectroscopy. Results: An ELISA platform was developed using nucleocapsid and spike proteins for COVID-19 serosurvey. The participants showed greater seropositivity for nucleocapsid (72%) than spike (55.3%), and males showed higher seropositivity than females for both the proteins. Antibody levels to both the proteins were higher in intensive care unit (ICU) than ward patients. Children showed lower seropositivity and antibody levels than adults. In contrast to ICU adults (81.3%), ICU children (33.3%) showed lower seropositivity for spike. Notably, the neutralization efficiency correlated with levels of anti-nucleocapsid antibodies. The levels of plasma metabolites were perturbed differentially in COVID-19 patients as compared with the naive controls. Interpretation & conclusions: Our results reflect the complexity of human immune response and metabolome to SARS-CoV-2 infection. While innate and cellular immune responses are likely to be a major determinant of disease severity and protection, antibodies to multiple viral proteins likely affect COVID-19 pathogenesis. In children, not adults, lower seropositivity rate for spike was associated with disease severity

Multi-level scoring approach to discover multi-targeting potency of medicinal plant phytochemicals against protein targets in SARS-CoV-2 and human ACE-2 receptor

SARS-CoV-2 pandemic has become a major threat to human healthcare and world economy. Due to the rapid spreading and deadly nature of infection, we are in a situation to develop quick therapeutics to combat SARS-CoV-2. In this study, we have adopted a multi-level scoring approach to identify multi-targeting potency of bioactive compounds in selected medicinal plants and compared its efficacy with two reference drugs, Nafamostat and Acalabrutinib which are under clinical trials to treat SARS-CoV-2. In particular, we employ molecular docking and implicit solvent free energy calculations (as implemented in the Molecular Mechanics -Generalized Born Surface Area approach) and QM fragmentation approach for validating the potency of bioactive compounds from the selected medicinal plants against four di?erent viral targets and one human receptor (Angiotensin-converting enzyme 2 -ACE-2) which facilitates the SARS-CoV-2entry into the cell. The protein targets considered for the study are viral 3CL main protease (3CLpro), papain-like protease (PLpro), RNA dependent RNA polymerase (RdRp), and viral spike protein-human hACE-2 complex (Spike:hACE2)including human protein target (hACE-2). Herein, thereliable multi-level scoring approach was used to validate the mechanism behind the multi-targeting potency of selected phytochemicals from medicinal plants. The present study evidenced that the phytochemicals Chebulagic acid, Stigmosterol, Repandusinic acid and Geranin exhibited efficient inhibitory activity against PLpro while Chebulagic acid was highly active against 3CLpro. Chebulagic acid andGeranin also showed excellent target specific activity against RdRp.Luteolin, Quercetin, Chrysoeriol and Repandusinic acid inhibited the interaction of viral spike protein with human ACE-2 receptor. Moreover Piperlonguminine and Piperine displayed significant inhibitory activity against human ACE-2 receptor. Therefore, the identified compounds namely Chebulagic acid, Geranin and Repandusinic acid can serve as potent multi-targeting phytomedicine for treating COVID-19

Correlación entre dos metodologías para la medición de anticuerpos contra la proteína spike del coronavirus del Síndrome Respiratorio Agudo Grave 2 / Correlation between two methodologies for the measurement of antibodies against the spike protein of coronavirus of the Severe Acute Respiratory Syndrome 2

Resumen El coronavirus del Síndrome Respiratorio Agudo Grave 2 (SARS-CoV-2) posee diversas proteínas estructurales que incluyen la proteína spike (S), principal blanco de las vacunas actuales. Existen diversas metodologías para la medición de anticuerpos contra ésta que brindan información acerca de la respuesta inmune frente a la vacunación. El objetivo de este trabajo fue determinar la correlación entre quimioluminiscencia (CLIA) y enzimoinmunoanálisis de adsorción (ELISA) para la medición de anticuerpos IgG anti-proteína S (IgG anti-S). Se recolectaron resultados serológicos de 169 individuos y se determinaron los niveles de anticuerpos por ambas metodologías. Del total de muestras, 106 arrojaron un resultado positivo por ambas metodologías y 15 resultaron discordantes (CLIA+, ELISA-), con índice Kappa de 0,80. La correlación entre ambas metodologías fue buena. Este estudio podría aportar al manejo y seguimiento de la población vacunada, con la finalidad de obtener un valor de corte para evaluar la aplicación de una dosis adicional.

Abstract Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) has several structural proteins including the spike (S) protein, which is the main target of current vaccines. There are various methodologies for the measurement of antibodies against it that provide information about the immune response to vaccination. The objective of this study was to determine the correlation between chemiluminescence (CLIA) and enzyme-linked immunoassay (ELISA) for the measurement of IgG anti-S protein (IgG anti-S) antibodies. Serological results were collected from 169 individuals and antibody levels were determined by both methodologies. Out of the total samples, 106 were positive by both methodologies and 15 were discordant (CLIA+, ELISA-), with a Kappa index of 0.80. The correlation between both methodologies was good. This study could contribute to the management and follow-up of the vaccinated population, in order to obtain a cut-off value to evaluate the application of an additional dose.

Resumo O coronavírus da Síndrome Respiratória Aguda Grave 2 (SARS-CoV-2) possui várias proteínas estruturais, incluindo a proteína spike (S), principal alvo das vacinas atuais. Existem várias metodologias para medir anticorpos contra ela que fornecem informações sobre a resposta imune diante da vacinação. O objetivo deste trabalho foi determinar a correlação entre quimioluminescência (CLIA) e enzimoimunoanálise de absorção (ELISA) para a medição de anticorpos IgG anti-proteína S (IgG anti-S). Foram coletados resultados sorológicos de 169 indivíduos e os níveis de anticorpos foram determinados por ambas as metodologias. Do total de amostras, 106 deram resultados positivos nas duas metodologias e 15 foram discordantes (CLIA+, ELISA-), com índice Kappa de 0,80. A correlação entre as duas metodologias foi boa. Este estudo poderia contribuir para a gestão e seguimento da população vacinada, visando a obter um valor de corte para avaliar a aplicação de uma dose adicional.

Antibody profile in post-vaccinated & SARS-CoV-2 infected individuals

Background & objectives: During the COVID-19 pandemic it was important to assess the antibody profile in individuals vaccinated with Covaxin (BBV152) and Covishield (ChAdOx1 nCoV-19) with both 28 and 84 days gaps between two doses, those infected with SARS-CoV-2 and post-COVID-19-infected individuals vaccinated with only one dose of either of the vaccines. The present study was aimed to assess these objectives. Methods: Fifty real time reverse transcription–polymerase chain reaction (qRT-PCR)-confirmed COVID-19-infected individuals, along with 90 COVID-19-naïve (BBV152 and ChAdOx1 nCov-19)–vaccinated individuals, were included in the study. Individuals who received a single dose of either vaccine with a confirmed past diagnosis of SARS-CoV-2 infection (n=15) were also included. Blood samples were collected strictly between the 4th and 5th wk after development of symptoms for SARS-CoV-2 infected individuals and after the first/second vaccination dose. Antibody profile assessment was done using whole-virus, spike-receptor binding domain (RBD) and nucleocapsid-specific ELISA kits along with neutralizing antibody kit. Results: There was an overall 97.7 per cent seropositivity rate in vaccinated individuals, and a strong correlation (R2=0.8, P<0.001) between neutralizing and spike-RBD antibodies. Among individuals who received two standard doses of ChAdOx1 nCoV-19 vaccine, the spike antibody levels developed were of higher titre with a longer prime boost interval than in those with shorter intervals (P<0.01). Individuals vaccinated with two doses as well as only one dose post-SARS-CoV-2 infection had high neutralizing and spike-specific antibodies. Interpretation & conclusions: High neutralizing and spike-specific antibodies were developed in individuals vaccinated only with one dose of either vaccine post-SARS-CoV-2 infection. With the main priority being vaccinating majority of the population in our country, single-dose administration to such individuals would be a sensible way to make the most of the limited supplies. Furthermore, neutralizing antibody levels observed in COVID-19-naïve vaccinees imply the need for booster vaccination.

Response of three wheat varieties to nitrogen levels, seeding rates and their combination; 2: Spike characters

To achieve larger production per unit area, sciences and farmers face a great defiance in improving cropping practices and elicitation new top yielding wheat varieties and also to establish the effects of these factors on the spike characters. Two years experiment were conducted to evaluate the effect of three nitrogen fertilizer levels (recommend rate 80 kg N/fed and 25% lower and higher than the recommended, i.e. 60 and 100 kg N/ fed, three seeding rates (40, 60 and 80 kg grains/fed) and there varieties (Giza-171, Gemmiza-12 and Shandawil-1), on spike characters of wheat at the Agricultural and experimental Research Station, Faculty of Agriculture, Cairo University, Giza, Egypt during 2018/2019 and 2019/2020 seasons. The experimental design was a split- split plot in randomized complete block arrangement with three replications. Nitrogen levels were allocated to the main plots, while the sub plots were assigned for seeding rates. Wheat varieties were distributed at random in the sub-sub plots. Each sub-sub plots area 4 m (2 x 2m). Generally, results indicated that significant effect on spike length and number of grains/ spike in both seasons and on weight of grains/ spike and 1000-grain weight in one season, where the tallest and heaviest spike as well as the heaviest 1000-grain weight were produced at the 100 kg N/fed in both seasons but the highest number of grains/spike was obtained at 80 kg N/fed in one season. It could be concluded that application nitrogen at the rate of 100 kg/fed proceed the favorable effect on spike characters under the environmental conditions of the experimental site and the similar conditions. Seeding rates caused a significant effect on all studied traits in one season, so the highest values were at 80 kg grains/fed, but this effect on 1000-grain weight was true in both seasons, where the highest value was at 60 kg grains/fed. Moreover, varieties were significantly differed in all spike character in both seasons except number and weight of grains/spike in one season where Giza-12 variety surpassed others. Al studied interactions had significant effect on all studied traits either in one or two season. Planting Giza-171 with 80 kg grains/fed and application of 100 kg N/fed was the pest treatment.

Optimization of SARS-CoV-2 spike protein receptor binding domain expression in Pichia pastoris and evaluation of its immunogenicity / 中华微生物学和免疫学杂志

Objective:To effectively express the receptor binding domain (RBD) of SARS-CoV-2 spike protein in Pichia pastoris and to evaluate its immunogenicity. Methods:The gene encoding the RBD protein was synthesized and cloned into the pPICZαA plasmid. After linearization, the plasmid was transferred and integrated into the genome of Pichia pastoris. The expressed RBD protein in culture supernatant was analyzed by Western blot and Biolayer interferometry. After screening, a single clone expressing the RBD protein was selected. The high-level expression of RBD protein was achieved by optimizing the fermentation process, including the salt concentration adjusting of the medium and induction condition optimization (pH, temperature and duration). The immunogenicity of the expressed RBD protein was evaluated in a mouse model. Results:A single clone with a high expression level of RBD protein was obtained and named RBD-X33. The expression level of RBD protein in the fermentation supernatant reached up to 240 mg/L after optimization of the induction condition (HBSM medium, pH=6.5±0.3, 22℃ and 120 h). In the mouse experiment, the recombinant RBD protein was formulated with Alum+ CpG dual adjuvant and injected into mice. The binding IgG antibody levels were up to 2.7×10 6 tested by ELISA and the neutralizing antibody levels were up to 726.8 tested by live virus neutralizing antibody assay (prototype). Conclusions:The RBD protein could be efficiently expressed in Pichia pastoris and induce stronger immune response in animals. This study suggested that the recombinant SARS-CoV-2 RBD protein expressed in Pichia pastoris could serve as a candidate antigen in the development of SARS-CoV-2 vaccine.

Variation of SARS-CoV-2 spike protein and its effects on neutralization sensitivity / 中华微生物学和免疫学杂志

The COVID-19 epidemic that occurred at the end of 2019 spreads rapidly to all parts of the world, putting the global public health system to a severe test. With the continuation of the epidemic, SARS-CoV-2 variants are constantly emerging. In particular, the mutation of the spike protein can cause changes in the infectivity and antigenicity of the virus, resulting in an increase in the infectivity and a decline in the protective efficacy of existing vaccines, and even the replacement of epidemic strains. This is also one of the reasons why the epidemic has not been effectively controlled so far. Nowadays, the main circulating variants have changed their characteristics to a certain extent, and the neutralization sensitivity of some variants to neutralizing monoclonal antibodies, immune sera and convalescent sera has decreased to a certain extent compared with the original strains. The emergence of variants is not only related to the characteristics of the virus itself, but also to the changes of transmission host and the chronic infection in people with deficient immunity. The emerging variants should be closely monitored, and their functional characteristics should be systematically studied so as to provide data for vaccine research and development and the designation of immunization strategies.