BackgroundViral infections constitute a primary trigger for asthma exacerbations. While vaccines protect against viral infections by eliciting a Th1 immune response, the impact of the asthmatic immune milieu which is characterized by Th2 cytokine dominance and elevated IgE levels on post-vaccination antibody production remains elusive. Therefore, vaccination protocols tailored to asthma patients need to be formulated.MethodsThe levels of IgG specific for SARS-CoV-2 S protein were measured in the sera of vaccinated and unvaccinated individuals by ELISA. The differences in antibody titers between asthma patients and healthy controls, as well as among distinct asthma subgroups were analyzed.ResultsThe vaccinated individuals had significantly elevated serum antibody levels compared to their unvaccinated counterparts. There were no significant differences in the antibody titers of asthma patients and healthy controls after completion of the three-dose vaccination regimen. Furthermore, no discernible variations in antibody titers were detected among the asthma subgroups.ConclusionAsthma patients can safely adhere to the same vaccination strategies as the general healthy population, negating the need for any specialized vaccination protocols based solely on the asthmatic immune landscape.

Severe fever with thrombocytopenia syndrome (SFTS) is a life-threatening tick-borne disease characterized by cytokine dysregulation and immune-mediated hyperinflammation. This multicenter retrospective study analyzed the dynamics of 17 cytokines across acute and recovery phases using 287 serum samples collected between 2010 and 2023 from high-incidence regions of China, evaluating their associations with disease severity, sex, age, and antibody responses. The results demonstrated that elevations of interleukin (IL)-6, interferon (IFN)-α, IL-8, and IFN-γ-induced protein 10 (IP-10) during the acute phase were associated with hyperinflammation, while IL-10 balanced inflammatory control and may have contributed to viral persistence. During recovery, most cytokines declined; however, IL-8 and IP-10 remained elevated longer in some patients, reflecting heterogeneity in recovery trajectories. Severe cases exhibited significantly higher levels of IL-10, IFN-γ, IL-6, IFN-α, tumor necrosis factor (TNF)-α, IL-8, and IP-10, underscoring their potential as biomarkers for disease severity prediction. Sex-based differences revealed higher IFN-γ and IL-8 levels in females, potentially due to hormonal and genetic factors, while older patients exhibited elevated IL-10, IFN-γ, and IFN-α, reflecting immune dysregulation and age-related shifts in adaptive immunity. Correlation analysis revealed distinct immune response patterns, with IL-10 strongly correlating with IFN-γ and minimal antibody-cytokine associations observed during the acute phase. In contrast, in the recovery phase, immunoglobulin G (IgG) negatively correlated with IL-10, IFN-γ, and IP-10, and immunoglobulin M (IgM) positively correlated with IL-10, IFN-γ, IL-6, IFN-α, TNF-α, IL-8, and IP-10, reflecting dynamic immune regulation and the interplay between humoral and cellular immunity. These findings provide critical insights into the immunopathogenesis of SFTS, supporting the development of cytokine-targeted therapies and advanced diagnostic tools to improve clinical outcomes.

What is already known about this topic?:Severe fever with thrombocytopenia syndrome (SFTS) is a serious tick-borne disease in East Asia with high mortality, particularly affecting the elderly. Since its discovery in 2010, inconsistencies in small-scale studies and the lack of decade-long research on antibody levels in large population samples after natural infection, along with the absence of an effective vaccine, highlight the need for large-scale, long-term data in high-incidence regions of China. What is added by this report?:This study of 1,410 serum samples from SFTS patients in high-incidence regions of China reveals that immunoglobulin M (IgM) levels peak at 8-14 days post-infection, declining to nearly undetectable levels by 180 days. Immunoglobulin G (IgG) and neutralizing antibodies (NAb) levels peak at 22-180 days, persisting up to 10 years. IgM levels correlate with viral load and various immune and coagulation parameters, with lower levels observed in fatal cases. During convalescence, elderly patients have lower IgG levels, whereas females exhibit higher IgG levels compared with males. What are the implications for public health practice?:The study's findings on long-term antibody dynamics in SFTS patients can significantly improve vaccine development, optimize therapy scheduling, inform public health policies, and enhance diagnostic tools, leading to better disease management and prevention in high-incidence areas.

What is already known about this topic?:Mucosal IgA plays a crucial role in host immunity against respiratory viruses. Recent studies suggest that it has the potential to mitigate the transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant. However, a comprehensive population-based analysis examining mucosal IgA levels following the winter 2022 wave of the coronavirus disease 2019 (COVID-19) pandemic is yet to be conducted.What is added by this report?:In our study involving 3,421 participants, we documented IgA responses subsequent to SARS-CoV-2 infection. A significant proportion of individuals sustained increased levels of IgA for over six months. These levels were also observed in individuals with prior infections who underwent asymptomatic reinfections, indicating an active production of IgA antibodies. Further, individuals with multiple vaccinations or severe symptoms tended to display elevated IgA levels after recovery.What are the implications for public health practice?:IgA in the nasal mucosa is crucial for defense against SARS-CoV-2 infection. These insights can enhance our knowledge of immune responses following infection and have provided certain reference values for disease prevention and control strategies.

Following the national dynamic zero-COVID strategy adjustment, the utilization of broad-spectrum nasal neutralizing antibodies may offer an alternative approach to controlling the outbreak of Omicron variants between late 2022 and early 2023 in China. This study involved an investigator-initiated trial (IIT) to assess the pharmacokinetic, safety and efficacy of the F61 nasal spray. A total of 2,008 participants were randomly assigned to receive F61 nasal spray (24 mg/0.8 mL/dose) or normal saline (0.8 mL/dose) and 1336 completed the follow-up in the IIT. Minimal absorption of F61 antibody into the bloodstream was detected in individuals receiving F61 nasal spray for seven consecutive days. No treatment-emergent adverse reactions of grade 3 severity or higher were reported. In the one-dose cohort, the 7-day cumulative SARS-CoV-2 infection rate was 79.0% in the F61 group and 82.6% in the placebo group, whereas, in the multiple-dose (once daily for 7 consecutive days) cohort, the rates were 6.55% in the F61 group and 23.83% in the placebo group. The laboratory-confirmed efficacy of F61 was 3.78% (-3.74%-10.75%) in the one-dose cohort and 72.19% (57.33%-81.87%) in the multiple-dose cohort. In the real-world study, 60,225 volunteers in four different regions were administered the F61 nasal spray based on the subject's wishes, over 90% efficacy rate was observed against different Omicron variants. The F61 nasal spray, with its favourable safety profile, could be a promising prophylactic monoclonal antibody against SARS-CoV-2 VOCs.

In recent years, there have been significant advancements in the research of Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV). However, several limitations and challenges still exist. For instance, researchers face constraints regarding experimental conditions and the feasibility of sample acquisition for studying SFTSV. To enhance the quality and comprehensiveness of SFTSV research, we opted to employ PMA-induced THP-1 cells as a model for SFTSV infection. Multiple time points of SFTSV infection were designed to capture the dynamic nature of the virus–host interaction. Through a comprehensive analysis utilizing various bioinformatics approaches, including diverse clustering methods, MUfzz analysis, and LASSO/Cox machine learning, we performed dynamic analysis and identified key genes associated with SFTSV infection at the host cell transcriptomic level. Notably, successful clustering was achieved for samples infected at different time points, leading to the identification of two important genes, PHGDH and NLRP12. And these findings may provide valuable insights into the pathogenesis of SFTSV and contribute to our understanding of host–virus interactions.

为了寻求SARS-CoV-2 IgM抗体阳性血清质控品的替代品,本研究成功表达纯化出抗SARS-CoV-2 S蛋白IgM单克隆抗体.研究确定了 IgM单克隆抗体最佳表达载体为含增强子sp163和信号肽2的组合以及第5d为目的蛋白收获的最佳时间.此外在研究J链的作用时发现转染细胞时不添加J链(nCoV-163-IgM3)的表达量明显高于添加J链(nCoV-163-IgM3 J)时的表达量,J链对蛋白稳定性也无明显影响,且nCoV-163-IgM3和nCoV-163-IgM3 J抗原结合活性之间的差别无统计学意义(P＞0.05),nCoV-163-IgM3和nCoV-163-1gM3 J对本研究所检测的WT-S1、Alpha-S1、Beta-S1、Delta-S1、Omicron-S1、BA.2-S1、BF.7-RBD、XBB.1-S1、BQ1.1-S1 等九种抗原均有结合活性,只有一株(BA.2.75-RBD)逃逸.纯化后的目的蛋白经还原剂(β-ME)还原后显示重链分子量大小为70kD左右,轻链分子量大小为25kD左右.目的蛋白均可与新型冠状病毒抗体检测试剂盒(胶体金,INNOVITA)、SARS-CoV-2 S蛋白IgM抗体酶联免疫吸附测定试剂盒(Elabscience)、抗SARS-CoV-2 S-RBD蛋白人IgM抗体酶联免疫吸附测定试剂盒(Proteintech)等三种试剂盒反应.

由呼吸道病毒引起的疾病严重威胁着人类的生命健康,为了建立一种快速高通量的呼吸道病毒核酸检测方法,本研究将多重PCR技术同液相芯片技术结合起来,针对呼吸道合胞病毒A型和B型、乙型流感病毒Victoria系和Yamagata系、甲型流感病毒H1型和H3型以及新冠病毒等常见的七种呼吸道病毒,初步建立了七重呼吸道病毒液相芯片核酸检测技术,评价了方法的特异性、敏感性和重复性,并使用来自安徽省疾控的25份临床急性期样本核酸对方法进行验证.结果显示,建立起的基于液相芯片多重核酸检测方法可特异性识别七种目标呼吸道病毒的靶基因序列,与包括副流感病毒在内的9种非目标呼吸道病毒无交叉反应.对七种病毒核酸进行十倍稀释液相检测,其中H3、BV、RSVB可以检出 102拷贝/μL,BY、RSVA和SARS-CoV-2可以检出 103拷贝/μL,对H1的检测限为104拷贝/μL.25份样本核酸检测结果与实际相符.结果表明,本研究建立的七重呼吸道病毒液相芯片核酸检测技术具有特异性强、敏感性高、稳定性好等特点,可用于临床样本的快速检测,为呼吸道类传染病的液相芯片诊断奠定了实验室基础.

Severe Fever with thrombocytopenia syndrome (SFTS) is a highly fatal viral infectious disease that poses a significant threat to public health. Currently, the phase and pathogenesis of SFTS are not well understood, and there are no specific vaccines or effective treatment available. Therefore, it is crucial to identify biomarkers for diagnosing acute SFTS, which has a high mortality rate. In this study, we conducted differentially expressed genes (DEGs) analysis and WGCNA module analysis on the GSE144358 dataset, comparing the acute phase of SFTSV-infected patients with healthy individuals. Through the LASSO–Cox and random forest algorithms, a total of 2128 genes were analyzed, leading to the identification of four genes: ADIPOR1, CENPO, E2F2, and H2AC17. The GSEA analysis of these four genes demonstrated a significant correlation with immune cell function and cell cycle, aligning with the functional enrichment findings of DEGs. Furthermore, we also utilized CIBERSORT to analyze the immune cell infiltration and its correlation with characteristic genes. The results indicate that the combination of ADIPOR1, CENPO, E2F2, and H2AC17 genes has the potential as characteristic genes for diagnosing and studying the acute phase of SFTS virus (SFTSV) infection.

Both Orthohantaviruses (HV) and Whenzhou Mammarenaviruses (WENV) are rodents borne viruses, allowing them to spread simultaneously in the same area and infect humans. To explore the potential threat of HV and WENV to public health safety, an environmental and laboratory investigation was conducted in 2020-2021, in Jiangxi province, China. A total of 461 small mammals of 7 species and paired sera from 43 suspected HFRS cases were collected from Jiangxi Province, China. Viral genomic RNA and specific antibodies against HV and WENV were detected to evaluate the epidemic situation of the two viruses. Hantaan virus (HTNV), seoul virus (SEOV) and WENV RNA were detected in the lungs of the captured mammals, which resulted 4.1% and 7.4% of HV and WENV RNA positive respectively. Co-infections of WENV and SEOV were detected from Rattus norvegicus, Mus musculus and Rattus flavipectus with an overall co-infection rate of 0.65%. The detection rates of antibodies in the blood against HV and WENV were 11.9% (55/461), and 13.2% (61/461) respectively. The prevalence of viral infection and viral genetic characters varied among the selected areas. In the paired sera of 43 suspected HFRS cases, 38 were with HV infection, 11 were with WENV IgG, and 7 with a 4-fold or more of WENV IgG titer elevation. These results revealed the fact of the co-circulating and coinfection of HV and WENV in the same area at the same time, which might impact on public health safety.

目的 分析我国近年来肾综合征出血热(HFRS)报告病例流行特征,加强对该病流行现状的理解.方法 从全国疾病监测信息报告管理系统获得2004-2021年HFRS病例信息,描述分析其分布动态变化特征以及病例诊断情况.结果 2004-2021年全国31个省(自治区、直辖市)都有病例报告,HFRS发病总体呈下降趋势,累计报告病例224396例,死亡2068例,年均发病率约为0.93/10万,病死率0.92％.病例呈高度分散又相对集中的分布特征,发病数前10位的省份报告发病185207例,占全国总报告病例数的82.54％.发病呈春夏季峰(4-7月)、秋冬季峰(10月至次年1月)季两个发病高峰,春夏季以5月或6月为高峰,11月或12月是秋冬季发病高峰,春夏季峰占32.20％,秋冬季峰占47.85％,秋冬季峰明显高于春夏季峰.男女性病例性别比为2.93:1,55岁以上人群发病率呈明显上升趋势,30～45岁人群发病率明显下降,14岁以下儿童病例占比出现上升趋势.职业分布仍以农民为主(占67.74％),待业和居家人群病例占比出现明显上升.结论 2004-2021年,中国HFRS报告病例数逐步下降到相对低位水平,伴随局部地区发病率的显著起伏;疫情分布地域扩大,部分地区出现再发疫情;高龄人群和儿童病例占比有升高趋势,应引起关注,并制定针对性的策略和措施.

Multiple new variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have constantly emerged, as the delta and omicron variants, which have developed resistance to currently gained neutralizing antibodies. This highlights a critical need to discover new therapeutic agents to overcome the variants mutations. Despite the availability of vaccines against coronavirus disease 2019 (COVID-19), the use of broadly neutralizing antibodies has been considered as an alternative way for the prevention or treatment of SARS-CoV-2 variants infection. Here, we show that the nasal delivery of two previously characterized broadly neutralizing antibodies (F61 and H121) protected K18-hACE2 mice against lethal challenge with SARS-CoV-2 variants. The broadly protective efficacy of the F61 or F61/F121 cocktail antibodies was evaluated by lethal challenge with the wild strain (WIV04) and multiple variants, including beta (B.1.351), delta (B.1.617.2), and omicron (B.1.1.529) at 200 or 1000 TCID50, and the minimum antibody administration doses (5-1.25 mg/kg body weight) were also evaluated with delta and omicron challenge. Fully prophylactic protections were found in all challenged groups with both F61 and F61/H121 combination at the administration dose of 20 mg/kg body weight, and corresponding mice lung viral RNA showed negative, with almost all alveolar septa and cavities remaining normal. Furthermore, low-dose antibody treatment induced significant prophylactic protection against lethal challenge with delta and omicron variants, whereas the F61/H121 combination showed excellent results against omicron infection. Our findings indicated the potential use of broadly neutralizing monoclonal antibodies as prophylactic and therapeutic agent for protection of current emerged SARS-CoV-2 variants infection.

Objective:To establish a quick on-site emergency detection method for severe fever with thrombocytopenia syndrome virus (SFTSV), dengue virus (DENV), and hantaan virus (HTNV).Methods:This research was based on the traditional TaqMan fluorescent probe technology, using the domestic rapid one-step quantitative RT-PCR kit, combined with the Magnetic induction cycler (Mic) qPCR instrument. The detection limit, specificity and repeatability of this method were evaluated by simulated samples, other virus infected samples and normal human blood samples.Results:Compared with the traditional RT-PCR assay, the required time of this method was greatly shortened, and the detection can be completed within 35 minutes. The limit of quantitation for SFTSV, DENV and HTNV are less than 100copies/PCR. No nonspecific amplification was found in the simulated negative samples and other virus infected samples. All the simulated positive sample for verification could be detected, and coefficient of variation Ct value of each group was less than 4%. Conclusions:The rapid fluorescence quantitative RT-PCR assays have certain application prospects for on-site emergency detection, and provide important technical supports and new directions for the prevention and control of common hemorrhagic fever viruses.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs), especially the latest Omicron, have exhibited severe antibody evasion. Broadly neutralizing antibodies with high potency against Omicron are urgently needed for understanding the working mechanisms and developing therapeutic agents. In this study, we characterized the previously reported F61, which was isolated from convalescent patients infected with prototype SARS-CoV-2, as a broadly neutralizing antibody against all VOCs including Omicron BA.1, BA.1.1, BA.2, BA.3 and BA.4 sublineages by utilizing antigen binding and cell infection assays. We also identified and characterized another broadly neutralizing antibody D2 with epitope distinct from that of F61. More importantly, we showed that a combination of F61 with D2 exhibited synergy in neutralization and protecting mice from SARS-CoV-2 Delta and Omicron BA.1 variants. Cryo-Electron Microscopy (Cryo-EM) structures of the spike-F61 and spike-D2 binary complexes revealed the distinct epitopes of F61 and D2 at atomic level and the structural basis for neutralization. Cryo-EM structure of the Omicron-spike-F61-D2 ternary complex provides further structural insights into the synergy between F61 and D2. These results collectively indicated F61 and F61-D2 cocktail as promising therapeutic antibodies for combating SARS-CoV-2 variants including diverse Omicron sublineages.

Objective:To establish a simple, rapid and low-cost 2019 novel coronavirus (2019-nCoV) neutralizing antibody detection method.Methods:The 2019-nCoV RBD specific immunoglobulin G (RBD-IgG) detection method was established based on the principle of quantum dot immunochromatography(QDs), and the detection was evaluated by using of sera from coronavirus disease 2019 (COVID-19) convalescent patients ( N = 97), vaccinated donors ( N = 82) and healthy donors ( N = 299). The suitability of fingertip blood was evaluated by matching blood samples with peripheral blood ( N=54). Results:The 2019-nCoV RBD-IgG detection method based on QDs was successfully established. The detection result of QDSs had strong correlation ( Spearman r > 0.73, P < 0.000 1) and good consistency ( Kappa=0.93, P < 0.01) with the result of micro-neutralization test(MNT). The sensitivity and specificity were 92% and 99%, respectively. There was high correlation ( Spearman r =0.932 6, P < 0.000 1) and no significant difference ( P=0.102 6) between result of fingertip blood and peripheral blood. Fingertip blood can be used as a surrogate sample for testing. Conclusions:The 2019-nCoV neutralizing antibody detection method established in this study can provide an immediate, efficient and low-cost method selection for the assessment of herd immunity status, and provide technical support for the herd immunity monitoring of 2019-nCoV vaccinated population and the prevention and control of the epidemic.

Background: Hantavirus causes hemorrhagic fever with renal syndrome, thus posing a major threat to human health in Jiangxi Province, China. Both Hantaan virus (HTNV) and Seoul virus (SEOV) have been found to be endemic in the province. Methods: Rodents were trapped from Gaoan Anyi and Tonggu counties in Jiangxi Province in 2020–2021. Hantavirus specific antibodies in the blood and RNA in the lung samples from the captured mammals were detected and analyzed. Results: A total of 889 small mammals from seven species were collected. Positive detection was observed for hantavirus antibodies in 9.8% (87/889), SEOV RNA in 1% (9/889) and HTNV RNA in 2.6% (23/889). The difference in detection rates between regions was significant. Phylogenetic analysis of the obtained partial sequences of M and S segments revealed that two distinct genotypes of HTNV and three genotypes of SEOV were co-circulating in the captured mammals, with a regionally specific distribution. Conclusion: Multiple distinct genotypes of hantavirus are co-circulating in the province. Further studies in broader areas remain needed to reveal the diversity of hantaviruses.

BACKGROUND:Chikungunya virus (CHIKV) reemerged and caused millions of human infections since 2004. The disease could be established, when the virus has been introduced to areas where the appropriate vectors are endemic. The differential diagnosis of CHIKV infection varies based on place of residence, travel history, and exposures. Serological tests are commonly used to diagnose CHIKV infection, but their availability and assessments of the performance of the diagnostics have been limited.OBJECTIVES:To develop and evaluate antibodies detection methods for chikungunya diagnosis and serological investigation.METHODS:Recombinant E2 protein based IgM capture enzyme-linked immunosorbent assay (Mac-ELISA) and double antigen sandwich ELISA (Das-ELISA) for detection of antibodies to Chikungunya virus were developed and evaluated. The repeatability was evaluated by testing of three reference sera at single dilutions in triplicated for 5 times. The sensitivity, specificity, accuracy, and agreement of the MAC-ELISA and Das-ELISA were obtained by comparing the detection results of 225 serum samples (45 positive; 180 negative) with a real-time RT-PCR assay and an IFA commercial tests manufactured by Euroimmun.RESULTS:The established ELISA assays were standardized by determining the optimal concentrations of the key reagents. The coefficient values of repeat testing were within 10% and 20% for intraassay and interassay precision, respectively. A sensitivity of 60.0% and 52.5%, a specificity of 96.2% and 96.8%, and an accuracy of 89.8% and 88.9% were obtained for the Mac-ELISA and Das-ELISA, respectively, when compared to a CHIKV qRT-PCR method. And a sensitivity of 100%, a specificity of 97.5% and 99.5%, and an accuracy of 97.8% and 99.6% were yielded respectively when using the IIFT as a reference method, which showed a highly consistence to the commercial IIFT assay with a Kappa value greater than 0.90.CONCLUSIONS:The Mac-ELISA and Das-ELISA based on recombinant E2 protein of CHIKV were developed and standardized, which could detect IgM or total antibodies against CHIKV in 2-3 hours with acceptable sensitivities and specificities. These assays can be used for laboratory diagnosis and serological investigation of CHIKV infections to evaluate the risk of CHIKV transmission.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has precipitated multiple variants resistant to therapeutic antibodies.In this study,12 high-affinity antibodies were generated from convalescent donors in early outbreaks using immune antibody phage display libraries.Of them,two RBD-binding antibodies (F61 and H121) showed high-affinity neutralization against SARS-CoV-2,whereas three S2-target antibodies failed to neutralize SARS-CoV-2.Following structure analysis,F61 identified a linear epitope located in residues G446-S494,which overlapped with angiotensin-converting enzyme 2 (ACE2) binding sites,while H121 recognized a conformational epitope located on the side face of RBD,outside from ACE2 binding domain.Hence the cocktail of the two antibodies achieved better performance of neutralization to SARS-CoV-2.Importantly,these two antibodies also showed efficient neutralizing activities to the variants including B.1.1.7 and B.1.351,and reacted with mutations of N501Y,E484K,and L452R,indicated that it may also neutralize the recent India endemic strain B.1.617.The unchanged binding activity of F61 and H121 to RBD with multiple mutations revealed a broad neutralizing activity against variants,which mitigated the risk of viral escape.Our findings revealed the therapeutic basis of cocktail antibodies against constantly emerging SARS-CoV-2 variants and provided promising candidate antibodies to clinical treatment of COVID-19 patients infected with broad SARS-CoV-2 variants.

The development of rapid serological detection methods re urgently needed for determination of neutralizing antibodies in sera. In this study, four rapid methods (ACE2-RBD inhibition assay, S1-IgG detection, RBD-IgG detection, and N-IgG detection) were established and evaluated based on chemiluminescence technology. For the first time, a broadly neutralizing antibody with high affinity was used as a standard for the quantitative detection of SARS-CoV-2 specific neutralizing antibodies in human sera. Sera from COVID-19 convalescent patients (N = 119), vaccinated donors (N = 86), and healthy donors (N = 299) confirmed by microneutralization test (MNT) were used to evaluate the above methods. The result showed that the ACE2-RBD inhibition assay calculated with either ACE2-RBD binding inhibition percentage rate or ACE2-RBD inhibiting antibody concentration were strongly correlated with MNT (r ≥ 0.78, p < 0.0001) and also highly consistent with MNT (Kappa Value ≥ 0.94, p < 0.01). There was also a strong correlation between the two evaluation indices (r ≥ 0.99, p < 0.0001). Meanwhile, S1-IgG and RBD-IgG quantitative detection were also significantly correlated with MNT (r ≥ 0.73, p < 0.0001), and both methods were highly correlated with each other (r ≥ 0.95, p < 0.0001). However, the concentration of N-IgG antibodies showed a lower correlation with the MNT results (r < 0.49, p < 0.0001). The diagnostic assays presented here could be used for the evaluation of SARS-CoV-2 vaccine immunization effect and serological diagnosis of COVID-19 patients, and could also have guiding significance for establishing other rapid serological methods to surrogate neutralization tests for SARS-CoV-2.

Objective:To explore an early, rapid and accurate detection method of severe acute respiratory syndrome coronavirus 2 (2019-nCoV) antigen and improve the detection rate of patients with 2019-nCoV.Methods:We detected the characteristics of monoclonal antibodies (mAbs) against 2019-nCoV generated previously and established a double antibody sandwich ELISA against S protein of the virus.Results:All 12 mAbs against 2019-nCoV screened in our previous study were able to recognize purified virion and S protein. They were good candidates for detecting antibody to 2019-nCoV antigen. A double antibody sandwich ELISA established in this study could rapidly and effectively detect 2019-nCoV S protein with high sensitivity. The detection limit of 2019-nCoV S protein was lower than 1 ng/ml.Conclusions:This method could specifically detect 2019-nCoV antigen, and provided a meaningful reference for early, sensitive and specific diagnosis of COVID-19 infection.