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Background. Since the start of the COVID-19 pandemic, Chad has had 7,417 confirmed cases and 193 deaths, one of the lowest in Africa. Objective. This study assessed SARS-CoV-2 immunity in N'Djamena. Methods. In August-October 2021, eleven N'Djamena hospitals collected outpatient data and samples. IgG antibodies against SARSCoV- 2 nucleocapsid protein were identified using ELISA. "Bambino Gesu" Laboratory, Rome, Italy, performed external quality control with chemiluminescence assay. Results. 25-34-year-old (35.2%) made up the largest age group at 31.9 12.6 years. 56.4% were women, 1.3 women/men. The 7th district had 22.5% and the 1st 22.3%. Housewives and students dominated. Overall seroprevalence was 69.5% (95% CI: 67.7-71.3), females 68.2% (65.8-70.5) and males 71.2% (68.6-73.8). >44-year-old had 73.9% seroprevalence. Under-15s were 57.4% positive. Housewives (70.9%), civil servants (71.5%), and health workers (9.7%) had the highest antibody positivity. N'Djamena's 9th district had 73.1% optimism and the 3rd district had 52.5%. Seroprevalences were highest at Good Samaritan Hospital (75.4%) and National General Referral Hospital (74.7%). Conclusion. Our findings indicate a high circulation of SARS-CoV- 2 in N'Djamena, despite low mortality and morbidity after the first two COVID-19 pandemic waves. This high seroprevalence must be considered in Chad's vaccine policy.
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The global pandemic coronavirus pneumonia (COVID-19), the disease infected by the new coronavirus (SARS-CoV-2), is extremely contagious. It is mainly spread among people through respiratory droplets, aerosols, direct or indirect contact, fecal-oral transmission, and cold chain transportation. Especially, patients who are in the incubation period or have no obvious symptoms already have the ability to infect others. SARS-C0V-2 is a positive-sense single-stranded RNA virus, with a single linear RNA segment. Each SARS-CoV-2 virion is 60-140 mm in diameter. Like other coronaviruses, SARS-CoV-2 has four structural proteins, known as the spike (S), envelope(E), membrane (M), and nucleocapsid (N) proteins. To date, a variety of detection methods for the SARS-CoV-2 have been developed based on the virus structural basis and 'etiological characteristics, which would provide an effective guarantee for the diagnosis of COVID-19 patients and the control of the epidemic. In order to help for the early diagnosis and prevention of COVID-19, the pathogenic characteristics and recent progresses of detection base on nucleic acid, immunology and biosensors of the SARS-CoV-2 are reviewed in this paper.
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Background: Studies suggest perinatal infection with SARSCoV- 2 can induce adverse birth outcomes, but studies published to date have substantial limitations. Most have identified cases based upon their presentation for clinical care, and very few have examined pandemic-related stress which may also impact adverse birth outcomes. Objective(s): To evaluate the relationships between SARSCoV- 2 infection in pregnancy and pandemic-related stress with birth outcomes. Study Design: We conducted an observational study of 211 mother-newborn dyads in three urban cohorts participating in the Environmental Influences on Child Health Outcomes (ECHO) Program. Serology for SARS-CoV-2 was assessed in a convenience sample of prenatal maternal, cord serum or dried blood spots from births occurring between January 2020-September 2021. Specimens were assessed for IgG, IgM, and IgA antibodies to nucleocapsid, S1 spike, S2 spike, and receptor-binding domain. A Pandemic-related Traumatic Stress (PTS) scale was based on the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition Acute Stress Disorder criteria. Result(s): 36% were positive for at least one antibody type, chiefly IgG. Self-report of infection was not significantly correlated with combined serology. There were no differences in gestational age (GA), birth weight, preterm birth (PTB), or low birth weight (LBW) among seropositive mothers. However, IgM seropositive mothers had children with lower BW (434g, 95% CI: 116- 752), BW Z score-for-GA (0.73 SD, 95% CI 0.10-1.36) and were more likely to deliver preterm (OR 8.75, 95% CI 1.22-62.4). Associations with LBW sustained in sensitivity analyses limited to pre-vaccine samples, and PTS symptoms were not associated with birth outcomes. The addition of PTS did not substantially change associations with BW, although associations with PTB attenuated to near-significance. Conclusion(s): We identified decreased birth weight and increased prematurity in mothers IgM seropositive to SARS-CoV-2, independent of PTS. Though there are limits to interpretation, the data support efforts to prevent SARS-CoV-2 infections in pregnancy.
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Given the rapid spread of coronavirus disease 2019 (COVID-19) globally, test systems are needed for its diagnosis, timely treatment, and introduction of quarantine measures. In the shortest possible time, a diagnostic system based on real-time reverse-transcription polymerase chain reaction to detect the ribonucleic acid of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal and oropharyngeal smears was developed and registered. The method determines the nucleocapsid and small-membrane protein genes and the human PGK1 gene, acting as internal control reactions. The nucleotide sequences of SARS-CoV-2 were analyzed, and primers were selected. The conditions for carrying out real-time reverse-transcription polymerase chain reaction and the composition of a set of reagents were set. The diagnostic sensitivity and specificity of the kit were tested on biological samples, with the addition of inactivated SARSCoV-2. The high analytical characteristics of the developed set of reagents were demonstrated, with a sensitivity of at least 103 GE/mL and a specificity of 100%, and no false-positive or false-negative results were recorded. The high specificity of the test system was shown on a representative sample of genetic materials of respiratory viral pathogens. Clinical and laboratory tests of the diagnostic "SARS-CoV-2 test” were conducted in the N.F. Gamalei National Research Center for Epidemiology and Microbiology. A set of reagents for the detection of ribonucleic acid of SARS-CoV-2 through on real-time reverse-transcription polymerase chain reaction for in vitro diagnostics "SARS-CoV-2 test” was registered in the Russian Federation as a medical device (Registration certificate no. RZN 2020/10632, dated 06/03/2020). The article can be used under the CC BY-NC-ND 4.0 license © Authors, 2022.
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Background & Aim: Immunological characteristics of COVID-19 show pathological hyperinflammation associated with lymphopenia and dysfunctional T cell responses. These features provide a rationale for restoring functional T cell immunity in COVID-19 patients by adoptive transfer of SARS-CoV-2 specific T cells. Methods, Results & Conclusion(s): To generate SARS-CoV-2 specific T cells, we isolated peripheral blood mononuclear cells from 7 COVID-19 recovered and 13 unexposed donors. Consequently, we stimulated cells with SARS-CoV-2 peptide mixtures covering spike, membrane and nucleocapsid proteins. Then, we culture expanded cells with IL-2 for 21 days. We assessed immunophenotypes, cytokine profiles, antigen specificity of the final cell products. Our results show that SARSCoV- 2 specific T cells could be expanded in both COVID-19 recovered and unexposed groups. Immunophenotypes were similar in both groups showing CD4+ T cell dominance, but CD8+ and CD3+CD56+ T cells were also present. Antigen specificity was determined by ELISPOT, intracellular cytokine assay, and cytotoxicity assays. One out of 14 individuals who were previously unexposed to SARS-CoV-2 failed to show antigen specificity. Moreover, ex-vivo expanded SARS-CoV-2 specific T cells mainly consisted of central and effector memory subsets with reduced alloreactivity against HLA-unmatched cells suggesting the possibility for the development of third-party partial HLA-matching products. In conclusion, our findings show that SARSCoV- 2 specific T cell can be readily expanded from both COVID-19 and unexposed individuals and can therefore be manufactured as a biopharmaceutical product to treat severe COVID-19 patients.Copyright © 2023 International Society for Cell & Gene Therapy
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We conducted a retrospective study in the adult primary immunodeficiency clinic at UAB examining COVID-19 infection and COVID-19 antibody response from vaccination, natural infection, and immunoglobulin replacement from February 2021 to November 2022. Our goal was to determine if nucleocapsid and spike antibodies could be found in our PID patients and if these antibodies could be derived from natural infection, vaccination, or antibody replacement exclusively or combinatory. We hypothesized that increasing antibodies would be detected in our population as the COVID period extended. Two hundred and forty-five subjects were tracked over 336 clinic visits during this period. Our PID population included subjects with CVID, XLA, thymoma, hypogammaglobulinemia, IgA deficiency, IgG subclass deficiency, specific antibody deficiency, Down syndrome, IgM deficiency, and patients with recurrent sinopulmonary infections. We had 196 females and 45 males in our study. In our patient population, 47% of our patient had known COVID-19 infection. Of those 47%, 21% of those infected patients had COVID-19 at least twice. Of those infected, three did not have COVID-19 spike antibodies and chose not to get vaccinated either. Two of those patients were not on IVIG and one was on Pangyza. Of those infected, 70% (n = 80) were on IgG infusions compared to those uninfected, 77% (n = 96) were on IgG infusions. Of interest, we had three XLA patients and all three had COVID-19 infection in the summer 2021. Two of them tested positive for nucleocapsid and spike antibodies in high titers and they were receiving Gammagard or Gamunex infusions, suggesting that these immunoglobulin preparations contain COVID-19 antibodies. We are still in the process of analyzing our data to see if diagnosis, IgG preparations, date of testing, B cell numbers, and drugs play a role in producing nucleocapsid antibodies and high spike antibody titers.Copyright © 2023 Elsevier Inc.
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Introduction In this study, we aimed to monitor anti-spike and anti-nucleocapsid antibodies positivity in healthcare workers (HCWs) vaccinated with two doses of inactivated CoronaVac (Sinovac, China) vaccine. Methods Overall, 242 volunteer HCWs were included. Of the participants, 193 were HCWs without history of prior documented COVID-19 (Group 1), while 49 had history of prior documented COVID-19 before vaccination (Group 2). The participants were followed up for SARS-CoV-2 antibodies positivity at four different blood sampling time points (immediately before the second vaccine dose and at the 1st, 3rd months and 141-150 days after the second dose). We investigated the serum IgG class antibodies against SARS-CoV-2 RBD region and IgG class antibodies against SARS-CoV-2 nucleocapsid antigen by chemiluminescent microparticle immunoassay (CMIA) method using commercial kits. Results We found positive serum anti-RBD IgG antibody in 76.4% of the participants (71% in Group 1;98% in Group 2) 28 days after the first dose. When the antibody levels of the groups were compared at the four blood sampling time points, Group 2 anti-RBD IgG levels were found to be significantly higher than those in Group 1 at all follow-up time points. Although anti-RBD IgG positivity persisted in 95.6% of all participants in the last blood sampling time point, a significant decrease was observed in antibody levels compared to the previous blood sampling time point. Anti-nucleocapsid IgG antibody was positive in 12 (6.2%) of participants in Group 1 and 32 (65.3%) in Group 2 at day 28 after the first dose. At the fourth blood sampling time point, anti-nucleocapsid antibodies were found to be positive in a total of 20 (9.7%) subjects, 10 (6.1%) in Group 1 and 10 (23.8%) in Group 2. Conclusions In this study, it was determined that serum antibody levels decreased in both groups after the third month after the second dose in HCWs vaccinated with CoronaVac vaccine.Copyright © GERMS 2022.
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The nucleocapsid (N) protein is an abundant component of SARS-CoV-2 and a key analyte for lateral-flow rapid antigen tests. Here, we present new structural insights for the SARS-CoV-2 N protein using cryo-electron microscopy (EM) and molecular modeling tools. Epitope mapping based on structural data supported host-immune interactions in the C-terminal portion of the protein, while other regions revealed protein-protein interaction sites. Complementary modeling results suggested that N protein structures from known variants of concern (VOC) are nearly 100% conserved at specific antibody-binding sites. Collectively, these results suggest that rapid tests that target the nucleocapsid C-terminal domain should have similar accuracy across all VOCs. In addition, our combined structural modeling workflow may guide the design of immune therapies to counter viral processes as we plan for future variants and pandemics.
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Background & Aim: The new UCOE models we have recently developed, tested on many cell groups (including mouse ES and human iPS cells) and human mAb recombinant production studies as well, shows a powerful resistance to DNA methylation- mediated silencing and provides a higher and stable transfection profile. By the urgent need of vaccine development for COVID-19 during the pandemic, in this study we aimed to produce a potential recombinant vaccine by using the new generation UCOEs models of our own design. Methods, Results & Conclusion(s): Existing new-generation UCOE models and standard plasmid vectors to be used as control group were provided. Then, the sequences related to the PCR method were amplified for sufficient stock generation and cloning experiments. Verification in the plasmid vector was carried out in gel electrophoresis. Transfection of 293T cells was performed with clone plasmids carrying antigen genes and plasmids carrying genetic information of lentivirus units for the production of lentiviral vectors. Afterwards, 293T cells produced lentiviral vectors carrying antigen genes. Harvesting of these vectors was carried out during 48th and 72nd hours. Afterwards, CHO cells were transduced with appropriate quantity of lentiviral vectors. Isolation and purification of targeted proteins from the relevant medium were performed by HPLC and Q-TOF methods. A part of the spike and nucleocapsid gene sequences of COVID-19 were firstly cloned into our UCOE models. These UCOEs plasmids were then transferred into 293T cells along with plasmids carrying the genes that will form the lentivirus vectors (LVs). After harvesting and calculation of LV vector titers, the cloned vectors were then transfected into the CHO cells which the targeted recombinant production of the antigen proteins will be carried out. Antigenic structures were then isolated from the culture medium of CHO cells in following days for confirmation. Using HPLC and qTOF mass spectrometer methods, these structures in the medium were confirmed to be the units of spike and nucleocapsid proteins of the COVID-19 virus. In order to produce large amount of the recombinant antigens, the culture was then carried out with bioreactors in liters. At the final stage, these recombinantly produced antigen proteins were tested on rats to measure their immunogenic responses, and the study recently been completed successfully as a potential recombinant vaccine against COVID-19.Copyright © 2023 International Society for Cell & Gene Therapy
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Introduction: Covid-19 epidemic results from an infection caused by SARS-CoV2. Evolution-based analyses on the nucleotide sequences show that SARS-CoV2 is a member of the genus Beta-coronaviruses and its genome consists of a single-stranded RNA, encoding 16 proteins. Among the structural proteins, the nucleocapsid is the most abundant protein in virus structure, highly immunogenic, with sequence conservatory. Due to a large number of mutations in the spike protein, the aim of this study was to investigate bioinformatics, expression of nucleocapsid protein and evaluate its immunogenicity as an immunogenic candidate. Materials and Methods: B and T cell epitopes of nucleocapsid protein were examined in the IEDB database. The PET28a-N plasmid was transferred to E. coli BL21(DE3) expression host, and IPTG induced recombinant protein expression. The protein was purified using Ni-NTA column affinity chromatography, and the Western blotting method was utilized to confirm it. Finally, mice were immunized with three routes of purified protein. Statistical analysis of the control group injection and test results was carried out by t-test from SPSS software. Results: The optimized gene had a Codon adaptation index (CAI) of 0/97 Percentage of codons having high- frequency distribution was improved to 85%. Expression of recombinant protein in E. coli led to the production of BoNT/B-HCC with a molecular weight of 45 kDa. The total yield of purified protein was 43 mg/L. Immunization of mice induced serum antibody response. Statistical analysis showed that the antibody titer ratio was significantly different compared to the control sample and the antibody titer was acceptable up to a dilution of 1.256000. Conclusion: According to the present study results, the protein can be used as an immunogenic candidate for developing vaccines against SARS-CoV2 in future research.
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Background: To date, several types of laboratory tests for coronavirus disease 2019 (COVID-19) diagnosis have been developed. However, the clinical importance of serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antigen (N-Ag) remains to be fully elucidated. In this study, we sought to investigate the value of serum SARS-CoV-2 N-Ag for COVID-19 diagnosis and to analyze N-Ag characteristics in COVID-19 individuals. Methods: Serum samples collected from 215 COVID-19 patients and 65 non-COVID-19 individuals were used to quantitatively detect N-Ag via chemiluminescent immunoassay according to the manufacturer's instructions. Results: The sensitivity and specificity of the N-Ag assay were 64.75% (95% confidence interval (95% CI) [55.94-72.66%]) and 100% (95% CI [93.05-100.00%]), respectively, according to the cut-off value recommended by the manufacturer. The receiver operating characteristic (ROC) curve showed a sensitivity of 100.00% (95% CI [94.42-100.00%]) and a specificity of 71.31% (95% CI [62.73-78.59%]). The positive rates and levels of serum SARS-CoV-2 N-Ag were not related to sex, comorbidity status or disease severity of COVID-19 (all P < 0.001). Compared with RTâPCR, there was a lower positive rate of serum N-Ag for acute COVID-19 patients (P < 0.001). The positive rate and levels of serum SARS-CoV-2 N-Ag in acute patients were significantly higher than those in convalescent patients (all P < 0.001). In addition, the positive rate of serum SARS-CoV-2 N-Ag in acute COVID-19 patients was higher than that of serum antibodies (IgM, IgG, IgA and neutralizing antibodies (Nab)) against SARS-CoV-2 (all P < 0.001). However, the positive rate of serum SARS-CoV-2 N-Ag in convalescent COVID-19 patients was significantly lower than that of antibodies (all P < 0.001). Conclusion: Serum N-Ag can be used as a biomarker for early COVID-19 diagnosis based on appropriate cut-off values. In addition, our study also demonstrated the relationship between serum N-Ag and clinical characteristics.
Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , COVID-19 Testing , SARS-CoV-2 , Nucleocapsid , Antibodies, NeutralizingABSTRACT
Due to the high reproduction rate of COVID-19, it is important to identify and isolate infected patients at the early stages of infection. The limitations of current diagnostic methods are speed, cost, and accuracy. Furthermore, new viral variants have emerged with higher rates of infectivity and mortality, many with mutations at various primer binding sites, which may evade detection via conventional PCR kits. Therefore, a rapid method that is sensitive, specific, and cost-effective is needed for a point-of-care molecular test. Accordingly, we developed a rapid molecular SARS-CoV-2 detection kit with high specificity and sensitivity, RT-PCR, taking advantage of the loop-mediated isothermal amplification (LAMP) technique. Four sets of six primers were designed based on conserved regions of the SARS-CoV-2 genome: two outer, two inner and two loop primers. Using the optimized protocol, SARS-CoV-2 genes were detected as quickly as 10 min but were most sensitive at 30 min, detecting as little as 100 copies of template DNA. We then coupled the RT-LAMP with a lateral flow dipstick (LFD) for multiplex detection. The LFD could detect two genic amplifications on a single strip, making it suitable for multiplexed detection. The development of a multiplexed RT-LAMP-LFD reaction on crude VTM samples would be suitable for the point-of-care diagnosis of COVID-19 in diagnostic laboratories as well as in private homes.
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The coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2. This virus has a high mismatch repair proofreading ability due to its unique exonuclease activity, making it knotty to treat. The nucleocapsid protein can serve as a potential antiviral drug target, as this protein is responsible for multiple captious functions during the viral life cycle. Herein, we have investigated the potential to repurpose active antiviral compounds of plant origins for treating the SARS-CoV-2 infection. In the present study, we followed the molecular docking methodology to screen druggable natural plants' active compounds against the nucleocapsid protein of SARS-CoV-2. The virtual screening of all 68 compounds revealed that the top seven active compounds, such as withanolide D, hypericin, silymarin, oxyacanthine, withaferin A, Acetyl aleuritolic acid, and rhein, exhibit good binding affinity with druggable ADME properties, toxicity, and Pass prediction. The stability of the docked complexes was studied by conducting molecular simulations of 100 ns. MM-GBSA calculated the binding free energy uncovered that withanolide D, hypericin, and silymarin result in highly stable binding conformations in three different sites of the nucleocapsid protein. However, further investigation is needed in order to validate the candidacy of these inhibitors for clinical trials. HighlightsNatural plants' active compounds may aid in the inhibition of SARS-CoV-2 replication and COVID-19 therapeutics.Hypericin, silymarin, withanolide D, oxyacanthine, withaferin A, Acetyl aleuritolic acid, and rhein are effective against SARS-CoV-2 N protein.Studied natural plants' active compounds could be useful against COVID-19 and its associated organs comorbidities.ADMET properties of selected compounds favor these compounds as druggable candidates.Communicated by Ramaswamy H. Sarma.
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As there are limited data on B cell epitopes for the nucleocapsid protein in SARS-CoV-2, we sought to identify the immunodominant regions within the N protein, recognized by patients with varying severity of natural infection with the Wuhan strain (WT), delta, omicron and in those who received the Sinopharm vaccines, which is an inactivated, whole virus vaccine.Using overlapping peptides representing the N protein, with an in-house ELISA, we mapped the immunodominant regions within the N protein, in seronegative (n=30), WT infected (n=30), delta infected (n=30), omicron infected+vaccinated (n=20) and Sinopharm (BBIBP-CorV) vaccinees (n=30). We then investigated the sensitivity and specificity of these immunodominant regions and analysed their conservation with other SARS-CoV-2 variants of concern, seasonal human coronaviruses and bat Sarbecoviruses. We identified four immunodominant regions aa 29-52, aa 155-178, aa 274 to 297 and aa 365 to 388, were highly conserved within SARS-CoV-2 and the bat coronaviruses. The magnitude of responses to these regions varied based on the infecting SARS-CoV-2 variants, >80% of individuals gave responses above the positive cut-off threshold to many of the four regions, with some differences with individuals who were infected with different VoCs. These regions were found to be 100% specific, as none of the seronegative individuals gave any responses. As these regions were highly specific with high sensitivity, they have a potential to be used to develop diagnostic assays and to be used in development of vaccines.
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Background: The pandemic caused by SARS-CoV-2 also caused infection in some pregnant women. Some reports say this viral infection can show symptoms of preeclampsia. Material and Methods: We analyzed 25 pregnant women with SARS-CoV-2 infection with 4 patients presenting with symptoms of preeclampsia. we performed routine blood analysis, renal function, liver function, and IHC examination to see the expression of viral proteins in the placenta. Results: we obtained 4 patients with confirmed SARS-CoV-2 infection by RT-PCR. In these 4 cases, none of the cases showed expression of the SARS-CoV-2 viral protein in the placenta, and all 4 mothers were declared dead after treatment, and 2 babies delivered out of these 4 cases died. In one case we had fetal death in pregnancy while in one case prematurity. 2 babies born to mothers with SARS-CoV-2 infection with preeclampsia were born in good condition. There were no babies infected with SARS-CoV-2. Conclusion: We conclude that SAR-CoV-2 infection in pregnant women with comorbidities can lead to a poor prognosis for both mother and baby. We cannot yet conclude whether SARS-CoV-2 infection can cause preeclampsia, but SARS-CoV-2 infection can exacerbate preeclampsia symptoms.
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The type I interferon (IFN-I) is a critical component of the innate immune responses, and Coronaviruses (CoVs) from both the Alphacoronavirus and Betacoronavirus genera interfere with the IFN-I signaling pathway in various ways. Of the gammacoronaviruses that mainly infect birds, little is known about how infectious bronchitis virus (IBV), evades or interferes with the innate immune responses in avian hosts since few IBV strains have been adapted to grow in avian passage cells. Previously, we reported that a highly pathogenic IBV strain GD17/04 has adaptability in an avian cell line, providing a material basis for further study on the interaction mechanism. In the present work, we describe the suppression of IBV to IFN-I and the potential role of IBV-encoded nucleocapsid (N) protein. We show that IBV significantly inhibits the poly I: C-induced IFN-I production, accordingly the nuclear translocation of STAT1, and the expression of IFN-stimulated genes (ISGs). A detailed analysis revealed that N protein, acting as an IFN-I antagonist, significantly impedes the activation of the IFN-ß promoter stimulated by MDA5 and LGP2 but does not counteract its activation by MAVS, TBK1, and IRF7. Further results showed that IBV N protein, verified to be an RNA-binding protein, interferes with MDA5 recognizing double-stranded RNA (dsRNA). Moreover, we found that the N protein targets LGP2, which is required in the chicken IFN-I signaling pathway. Taken together, this study provides a comprehensive analysis of the mechanism by which IBV evades avian innate immune responses.
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SARS-CoV-2 genomic mutations outside the spike protein that may increase transmissibility and disease severity have not been well characterized. This study identified mutations in the nucleocapsid protein and their possible association with patient characteristics. We analyzed 695 samples from patients with confirmed COVID-19 in Saudi Arabia between 1 April 2021, and 30 April 2022. Nucleocapsid protein mutations were identified through whole genome sequencing. ð2 tests and t tests assessed associations between mutations and patient characteristics. Logistic regression estimated the risk of intensive care unit (ICU) admission or death. Of the 60 mutations identified, R203K was the most common, followed by G204R, P13L, E31del, R32del, and S33del. These mutations were associated with reduced risk of ICU admission. P13L, E31del, R32del, and S33del were also associated with reduced risk of death. By contrast, D63G, R203M, and D377Y were associated with increased risk of ICU admission. Most mutations were detected in the SR-rich region, which was associated with low risk of death. The C-tail and central linker regions were associated with increased risk of ICU admission, whereas the N-arm region was associated with reduced ICU admission risk. Consequently, mutations in the N protein must be observed, as they may exacerbate viral infection and disease severity. Additional research is needed to validate the mutations' associations with clinical outcomes.
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The mRNA vaccines (RVs) can reduce the severity and mortality of severe acute respiratory syndrome coronavirus (SARS-CoV-2). However, almost only the inactivated vaccines (IVs) but no RVs had been used in mainland China until most recently, and the relaxing of its anti-pandemic strategies in December 2022 increased concerns about new outbreaks. In comparison, many of the citizens in Macao Special Administrative Region of China received three doses of IV (3IV) or RV (3RV), or 2 doses of IV plus one booster of RV (2IV+1RV). By the end of 2022, we recruited 147 participants with various vaccinations in Macao and detected antibodies (Abs) against the spike (S) protein and nucleocapsid (N) protein of the virus as well as neutralizing antibodies (NAb) in their serum. We observed that the level of anti-S Ab or NAb was similarly high with both 3RV and 2IV+1RV but lower with 3IV. In contrast, the level of anti-N Ab was the highest with 3IV like that in convalescents, intermediate with 2IV+1RV, and the lowest with 3RV. Whereas no significant differences in the basal levels of cytokines related to T-cell activation were observed among the various vaccination groups before and after the boosters. No vaccinees reported severe adverse events. Since Macao took one of the most stringent non-pharmaceutical interventions in the world, this study possesses much higher confidence in the vaccination results than many other studies from highly infected regions. Our findings suggest that the heterologous vaccination 2IV+1RV outperforms the homologous vaccinations 3IV and 3RV as it induces not only anti-S Ab (to the level as with 3RV) but also anti-N antibodies (via the IV). It combines the advantages of both RV (to block the viral entry) and IV (to also intervene the subsequent pathological processes such as intracellular viral replication and interference with the signal transduction and hence the biological functions of host cells).
Subject(s)
COVID-19 , Nucleocapsid Proteins , Humans , Macau , SARS-CoV-2 , Vaccines, Inactivated , COVID-19/prevention & control , Antibodies, Neutralizing , mRNA VaccinesABSTRACT
The severe acute respiratory syndrome coronavirus (SARS-CoV-2) has infected millions of individuals and continues to be a major health concern worldwide. While reverse transcription-polymerase chain reaction remains a reliable method for detecting infections, limitations of this technology, particularly cost and the requirement of a dedicated laboratory, prevent rapid viral monitoring. Antigen tests filled this need to some extent but with limitations including sensitivity and specificity, particularly against emerging variants of concern. Here, we developed aptamers against the SARS-CoV-2 Nucleocapsid protein to complement or replace antibodies in antigen detection assays. As detection reagents in ELISA-like assays, our DNA aptamers were able to detect as low as 150 pg/mL of the protein and under 150 k copies of inactivated SARS-CoV-2 Wuhan Alpha strain in viral transport medium with little cross-reactivity to other human coronaviruses (HCoVs). Further, our aptamers were reselected against the SARS-CoV-2 Omicron variant of concern, and we found two sequences that had a more than two-fold increase in signal compared to our original aptamers when used as detection reagents against protein from the Omicron strain. These findings illustrate the use of aptamers as promising alternative detection reagents that may translate for use in current tests and our findings validate the method for the reselection of aptamers against emerging viral strains.
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Patients with end-stage chronic kidney disease treated with hemodialysis are at risk of infection and severe course of the new coronavirus infection. This opinion was based on the data obtained as a result of PCR testing during the active phase of the disease with detailed clinical symptoms. However, this diagnostic method does not allow one to fully assess the prevalence of infection in the population. The aim - studying of the frequency of SARS-CoV-2 infection in patients receiving hemodialysis treatment and the spectrum of antiviral antibodies, depending on the nature of the course of COVID-19. Material and methods. 100 patients with chronic kidney disease (stage 5D) treated at the outpatient Dialysis Center (MCVTP) were included in the study by a simple random sample. The assessment of SARS-CoV-2 infection was carried out by analyzing the material of smears obtained from the naso-oropharynx by PCR and blood serum samples by ELISA. The study excluded 14 patients with dubious results for the determination of serological markers SARS-CoV-2 and 1 patient with active infection, who was isolated from the RNA of the virus. Results. IgM and IgG antibodies were detected in 49 (57.6%) of the 85 examined patients. 24 of them (group 1) were diagnosed with COVID-19 infection with typical clinical symptoms 3-9 months ago, and 25 (group 2) had no clinical manifestations of the acute respiratory infection at the appropriate time suggesting an asymptomatic course of the disease. IgM class antibodies were detected with equal frequency in group 1 and in group 2 (33.3 vs 24.0%, respectively, p<0.6). IgG antibodies exclusively to the nucleocapsid N-protein (IgGn) were detected only in the latent form of the disease (32%), while antibodies against the S-protein (spike protein) of the virus (IgGs and IgGn+s) were detected more often in the manifest form compared to the asymptomatic one (100 vs 60%, respectively, p<0.05). Conclusion. In a random cohort of patient receiving hemodialysis treatment, more than half were asymptomatic.Despite a wide range of prevention measures, SARS-CoV-2 infection among patients treated with hemodialysis is more than 2 times higher than in the general population.Copyright © 2021 Geotar Media Publishing Group. All rights reserved.