Bioactive compounds of Jingfang Granules against SARS-CoV-2 virus proteases 3CLpro and PLpro.

OBJECTIVE: Jingfang Granules have been recommended for the prevention and treatment of corona virus disease 2019 (COVID-19). Through chemical analysis and bioactivity evaluation, this study aims to elucidate the potential effective components of Jingfang Granules. METHOD(S): The inhibitory acti-vities of Jingfang Granules extract against 3-chymotrypsin-like protease (3CLpro), papain like protease (PLpro), spike protein receptor-binding domain (S-RBD) and human cyclooxygenase-2 (COX-2) were evaluated using enzyme assay. The antitussive effects were evaluated using the classical ammonia-induced cough model. The chemical constituents of Jingfang Granules were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry (LC/MS). The 3CLpro and PLpro inhibitory activities of the major compounds were determined by enzyme assay, molecular docking, and site-directed mutagenesis. RESULT(S): Jingfang Granules exhibited 3CLpro and PLpro inhibitory activities, as well as COX-2 inhibitory and antitussive activities. By investigating the MS/MS behaviors of reference standards, a total of fifty-six compounds were characterized in Jingfang Granules. Sixteen of them were unambiguously identified by comparing with reference standards. The contents of the 16 major compounds were also determined, and their total contents were 2 498.8 mug/g. Naringin, nodakenin and neohesperidin were three dominating compounds in Jingfang Granules, and their contents were 688.8, 596.4 and 578.7 mug/g, respectively. In addition, neohesperidin and naringin exhibited PLpro inhibitory activities, and the inhibition rates at 8 mumol/L were 53.5% and 46.1%, respectively. Prim-O-glucosylcimifugin showed significant inhibitory activities against 3CLpro and PLpro, and the inhibitory rates at 8 mumol/L were 76.8% and 78.2%, respectively. Molecular docking indicated that hydrogen bonds could be formed between prim-O-glucosylcimifugin and amino acid residues H163, E166, Q192, T190 of 3CLpro (binding energy, -7.7 kcal/mol) and K157, D164, R166, E167, T301 of PLpro(-7.3 kcal/mol), respectively. Site-directed mutagenesis indicated amino acid residue K157 was a key active site for the interaction between prim-O-glucosylcimifugin and PLpro. CONCLUSION(S): Prim-O-glucosylcimifugin, neohesperidin, and naringin as the major compounds from Jingfang Granules could inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus proteases 3CLpro and PLpro. The results are valuable for rational clinical use of Jingfang Granules.

Performance of COVID Face Mask Detection Based on SVM Algorithm Using OpenCV DNN as Preprocessing Model

As COVID-19 became a pandemic in the world, wearing a mask has become one of the best measures to prevent the spread of the epidemic, so face mask recognition in public places has become a very important part of controlling the epidemic. This paper mainly tests the performance of the OpenCV DNN preprocessing model (OpenCV DNN + SVM) based on the SVM algorithm model in the face mask recognition dataset. The dataset I use is from Kaggle called COVID Face Mask Detection Dataset. This dataset contains 503 face images with masks and 503 face images without masks. I test the performance of using OpenCV DNN + SVM and using only the SVM algorithm to evaluate this study by setting a control experimental group. In this study, it was found that using OpenCV DNN + SVM, the accuracy of ROI parameters and SVM parameters can reach 93.06% and F1score can also reach 93.06% without a lot of adjustment. The accuracy rate can only reach 68.31%, and the F1score reaches 68.31%. Findings suggest that the method using OpenCV DNN + SVM can achieve slightly better results in the COVID Face Mask Detection Dataset, and can perform better than only using the SVM algorithm. In addition, using OpenCV DNN preprocessing model based on the SVM algorithm plays an important role in feature extraction in face mask recognition. If the developer does enough parameters tuning, the accuracy will also increase. © 2022 SPIE.

Classification and coding for Coronavirus disease 2019 by international classification ofdiseases: Updates and interpretation.

In the context of coronavirus disease 2019 (COVID-19), the leverage of specific codes of international classification of diseases(ICD) will substantially help standardize the process of data collection, classification and statistics of COVID-19-related conditions, thus facilitating the rapid research and development of diagnosis and treatment, dynamic monitoring of epidemic trend, as well as effectiveness evaluation of preventive and therapeutic measures taken in the fight against COVID-19. This review summarized and interpreted the latest ICD-10 and ICD-11 classification standards of COVID-19 related conditions and aimed to provide reference to improve and enrich the localized application of ICD coding standards for COVID-19 related conditions in China.Copyright © 2021, Peking Union Medical College Hospital. All rights reserved.

Value of Biofire Filmarray pneumonia panel in evaluating secondary infection in critically ill patients with Coronavirus disease 2019.

Objective To explore the application value of Biofire Filmarry pneumonia panel (PN) in detection of secondary and concomitant pathogen among critically ill patients with coronavirus disease 2019(COVID-19). Methods We consecutively included and analyzed the clinical data of critically ill patients with COVID-19 transferred to the ICU from February to April 2020 in the Sino-French Campus of Wuhan Tongji Hospital. Samples of Bronchoalveolar lavage fluid obtained by bedside bronchoscopy were sent for Biofire Filmarray PN and standard culture concomitantly. We compared the results of two methods and evaluated their concordance. Results In total, 21 critically ill patients with COVID-19 were included and 54 samples were tested, including 33 (61.1%) Biofire Filmarray PN tests (21 patients) and 21 (38.9%) standard cultures (14 patients), in which 19 pairs (38 samples) underwent both tests simultaneously. In Biofire Filmarray PN group, the turnaround time was about 1 hour. There were 74 positive results in 32 samples (97.0%) from 20 patients, including 29 cases(39.2%) of Acinetobacter baumannii complex, 21 cases (28.4%) of Pseudomonas aeruginosa, 16 cases (21.6%)of Klebsiella pneumoniae, 5 cases (6.8%) of Escherichia coli, 1 case (1.4%)each of Enterobacter cloacae, Haemophilus influenzae, and respiratory syncytial virus. In the standard culture group, the turnaround time was about 3 days. 19 positive results returned in 16 (76.2%) samples from 11 patients, including 8 cases (42.1%) of Pseudomonas aeruginosa, 6 cases (31.6%) of Acinetobacter baumannii, 4 cases (21.1%) of Stenotrophomonas malt and 1 case (5.3%) of Myxobacterium. Among the 19 pairs of "back-to-back" specimens, 15 pairs were concordant, and the agreement ratio was 78.9%. Conclusions Acinetobacter baumannii and Pseudomonas aeruginosa may be the common pathogens of secondary or concomitant infection in critically ill patients with COVID-19. Biofire Filmarray PN is a rapid diagnostic test and has application value in such patients;its sensitivity and accuracy require further investigation with larger sample sizes.Copyright © 2021, Peking Union Medical College Hospital. All rights reserved.

Will the COVID-19 Pandemic Outbreak Intensify the Resource Misallocation in China's Food Production?

Resource misallocation is one of the important manifestations of agricultural supply-side distortion and an important causal factor that hinders food production increase and affects food security. Did the COVID-19 pandemic intensify China's food production misallocation? The extent and consequences require quantitative assessment and scenario analysis. In this paper, we use a combination of input-output model and computable general equilibrium (CGE) model, and further incorporate the most important input factor in agriculture-intermediate inputs-into the model. At the same time, simulation of the pandemic impact from the demand and supply sides, respectively, and scenario analysis of the impact of the COVID-19 pandemic on China's food production. The results of the study show that: first, compared with the baseline level before the epidemic, the overall TFP growth of China's food industry chain decreased, and the TFP growth rate of the food distribution sector decreased most significantly. Second, there are significant factor misallocation distortions of capital, labor, and intermediate inputs. Third, in the short term, the period of the COVID-19 pandemic led to a decline in the vitality of the national labor market, but the return of non-farm employed labor in rural areas instead reduced the degree of labor misallocation in the food sector. Fourth, the demand side has a greater impact on China's food production, among which the consumer demand has a particularly strong impact on the resource allocation of food production, and the short-term shock will mainly have a more obvious impact on the allocation of labor factors and the allocation of intermediate input factors in the food industry chain. Accordingly, this paper proposes that in order to guarantee China's food security and adapt to the short-term characteristics of the era when the COVID-19 pandemic is rampant, China should make efforts in four areas: rational allocation of food production resources and factors, solid construction of the whole food industry chain, stable guarantee of the food market system and transfer to enhance social expectations.

Research on energy conservation in the hotel industry under Macau's dependence on external energy

The Macau Special Administrative Region has a special urban form. It is located on the coast of the Pearl River Delta, with a land area of only 33.6 square kilometers. The population living here is close to 700,000. It is the region with the highest population density in the world, and its energy mainly depends on imports. With the new coronavirus epidemic, Macau's tourism industry has been hit hard, and energy expenditures have risen with changes in the international situation. As an important economic support industry in Macau, the energy conservation development of the hotel industry is extremely important. Since 2007, Macau has launched "The Macau Energy Conservation Week, in conjunction with many departments and tourism companies in Macau, and the establishment of the Macau Green Hotel Award in the same year, have had a profound impact on Macau's energy consumption savings and improved the efficiency of Macau's hotel industry in terms of energy use. In pursuit of the goal of carbon peaking, the hotel industry in Macau has generally passed the ISO 50001:2018 Energy Management System (EnMS) certification, and most hotels have exceeded the Energy Use Intensity standard assessed by the Cornell Hotel Sustainability Benchmarking Index. Under the concept of green energy and other concepts, the hotel industry in Macau has now begun to use renewable energy for hotel use. Top hotels in Macau decreased by an average of 23.6% in 2021. After the return of Macau's sovereignty, Macau's unique political attributes and urban characteristics have different standards for the energy use of the entire industry and the characteristics of laws and regulations, which make it have different standards from mainland China. Based on preliminary research on the energy saving and environmental protection of the hotel industry in Macau, this research collects statistics on the energy saving data of the hotel industry and finally proposes improvements based on the energy utilization and environmental protection of the Macau Special Administrative Region and similar coastal peninsula cities. © The Authors.

PVT-COV19D: COVID-19 Detection Through Medical Image Classification Based on Pyramid Vision Transformer

With the outbreak of COVID-19, a large number of relevant studies have emerged in recent years. We propose an automatic COVID-19 diagnosis model based on PVTv2 and the multiple voting mechanism. To accommodate the different dimensions of the image input, we classified the images using the Transformer model, sampled the images in the dataset according to the normal distribution, and fed the sampling results into the PVTv2 model for training. A large number of experiments on the COV19-CT-DB dataset demonstrate the effectiveness of the proposed method. Our method won the sixth place in the (2nd) COVID19 Detection Challenge of ECCV 2022 Workshop: AI-enabled Medical Image Analysis - Digital Pathology & Radiology/COVID19. Our code is publicly available at https://github.com/MenSan233/Team-Dslab-Solution. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Overall management strategies for liver cancer patients during the COVID-19 outbreak.

The Corona Virus Disease 2019 (COVID-19) that occurred December of 2019 has a wide range of impacts, and its epidemic situation is grim. China has a large population of liver cancer, accounting for 50% of new cases of liver cancer worldwide. How to ensure the diagnosis, treatment and rehabilitation of liver cancer patients while preventing and controlling the epidemic situation is an issue that urgently need specialists pay attention to. The authors propose an overall management model for patients with liver cancer, combined with their own experience, in order to guide specialists to safely and effectively carry out clinical diagnosis and treatment of liver cancer during the prevention and control of epidemics, and to help liver cancer patients receive treatment.Copyright © 2020 by the Chinese Medical Association.

Telecytology Makes Significant Contribution in ROSE with Great Accuracy - Experience During the COVID-19 Pandemic at Stony Brook University Hospital

Introduction: Telecytology (TC) has been used in rapid onsite evaluation (ROSE) of touch preparations (TPs) from core biopsies and smears from fine-needle aspiration (FNA) procedures. Although TC was established at our institution in 2010, utilization has fluctuated. The COVID-19 pandemic highlighted the value of TC for maintaining high-quality patient care with the advantages of minimizing contact with hospital personnel and patients, conserving personal protective equipment (PPE), and saving cytopathologists' time. However, the accuracy of TC compared to on site evaluation by cytopathologists has been a concern. This study aimed to address this question. Material(s) and Method(s): 697 ROSEs were identified from our quality assurance (QA) data base in 2021 (Q2-Q4) including 1) TC;2) onsite cytopathologist (OC);and 3) onsite cytotechnologistonly (OCT). Discrepancy rates between ROSE and final diagnoses were compared between TC and OC groups. A student T-test was performed to determine the statistical significance of the discrepancy rate between TC and OC. Result(s): Results are summarized in Table 1. On average, there were 26% FNA and 74% Cores by TP. The difference in discrepancy rates between TC and OC during the 3 quarters in 2021 is not statistically significant (p=0.5012). The type of discrepancy for TC was all minor while 17% major and 83% minor for OC. Conclusion(s): The value of TC for ROSE was highlighted during the pandemic, allowing cytopathologists to participate in ROSE while minimizing interpersonal contact at procedures, conserving PPE, and saving cytopathologists' time. TC provides as high quality as OC for ROSE service with statistically insignificant minor discrepancies with the final diagnosis. Although pandemic-related restrictions are easing, we anticipate that TC will continue to play a major role in ROSE.

Mechanisms and control measures of COVID-19 related liver injuries.

Although the epidemic situation of Corona Virus Disease 2019 (COVID-19) has been controlled, the epidemic situation remains grim. The COVID-19 is highly infectious, with various clinical manifestations including liver injury. The authors make a preliminary investigation on the mechanisms of liver injury related to COVID-19, and put forward corresponding control measures for reference.Copyright © 2020 by the Chinese Medical Association.

Optimization of SARS-CoV-2 spike protein receptor binding domain expression in Pichia pastoris and evaluation of its immunogenicity.

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 pPICZalphaA 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 x 106 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.Copyright © 2022 Society of Microbiology and Immunology. All rights reserved.

Human IFN-κ Inhibited Respiratory RNA Virus Replication Dependent on Cell-to-Cell Interaction in the Early Phase

Background:Interferon kappa (IFN-κ) is a type I interferon (IFN-I) that inhibits virus replication by evoking interferon-stimulated genes (ISGs). However, as an evolutionarily ancient interferon, IFN-κ may function differently from the later emerged interferon-α and β.Methods:Conventional molecular biology methods were used to determine the localization of IFN-κ and its structure and function. In addition, we employed RT-PCR, western blot, and RNA-Seq technologies to characterize the ISGs expression profile and antiviral activities exerted by IFN-κ or IFN-α2.Results:Human IFN-κ exists in two forms upon ectopic expression, one located on the cell membrane and the other secreted outside the cells. The membrane-anchored IFN-κ showed the ability to induce ISGs and curtail RNA virus replication, whereas the secreted IFN-κ failed to do so. Structural analyses indicated that 1-27aa at the N-terminus was the signal peptide, and 28-37aa was predicted as the transmembrane region. However, our data demonstrated that both of them were not associated with membrane localization of IFN-κ;the former influenced the expression and secretion of IFN-κ, and the latter had an impact on the induction of ISGs. In addition, prokaryotic purified soluble mature human IFN-κ was also capable of inducing ISGs and inhibiting RNA virus replication. Importantly, human IFN-κ induced a faster ISG response but with a lower intensity and a shorter half-life than the response of IFN-α2. In contrast, IFN-α2 started to function later but was stronger and more durable than IFN-κ.Conclusions:Human IFN-κ-induced ISG response and inhibited respiratory RNA virus replication dependent on cell-to-cell interactions. In addition, compared with IFN-α2, IFN-κ exerted effects more rapidly in the early phase, with less intensity and a shorter half-life. Therefore, IFN-κ may constitute the first line of IFN-I against respiratory virus infections. © 2022 Journal of Bone and Joint Surgery Inc.. All rights reserved.

An agent-based model for public travel decision-making considering risk perception on the pandemic

Travel is an essential part of life for most people. Tourism is a very important part of the industry in most countries, and the prosperity of tourism is of great significance to promote the economic development of a country. After the outbreak of the Covid-19 pandemic, the development of tourism has entered a through. To explore public travel decision-making considering risk perception under the pandemic, we developed an agent-based model. In the model, we assumed that agents make decisions based on their willingness to travel and risk perception. We also combined the model with a model of opinion dynamics to explore the effect of government risk information on the number of trips. Our results show that individual travel probability decrease when considering risk perception on the pandemic. In the case of medium government credibility, the risk information released by the government has less impact on the number of people traveling. © 2022 The Authors. Published by Elsevier B.V.

Inorganic-based Surface Materials with Anti-SARS-CoV-2 Properties and Their Mechanisms of Action

The COVID-19 outbreak caused by SARS-CoV-2 has posed a serious threat to human health. The wide⁃ spread of the virus has increased the demand for anti-virus surface materials，especially in public places. This article reviews a series of inorganic surface materials with antiviral properties，including metals and its derivatives，graphene and its derivatives，and zeolites，and their antiviral mechanisms. The challenges and development prospects are summarized and prospected. © 2022 Higher Education Press. All rights reserved.

[Spatiotemporal changes of COVID-19 outbreak in Shanghai].

Objective: To clarify the epidemiological characteristics and spatiotemporal clustering dynamics of COVID-19 in Shanghai in 2022. Methods: The COVID-19 data presented on the official websites of Municipal Health Commissions of Shanghai during March 1, 2022 and May 31, 2022 were collected for a spatial autocorrelation analysis by GeoDa software. A logistic growth model was used to fit the epidemic situation and make a comparison with the actual infection situation. Results: Pudong district had the highest number of symptomatic and asymptomatic infectants, accounting for 29.30% and 35.58% of the total infectants. Differences in cumulative attack rates and infection rates among 16 districts (P<0.001) were significant. The rates were significantly higher in Huangpu district than in other districts. The attack rate of COVID-19 from March 1, 2022 to May 31, 2022 had a global spatial positive correlation (P<0.05). Spatial distribution of COVID-19 attack rate was different at different periods. The global autocorrelation coefficient from March 16 to March 29, April 6 to April 12 and May 18 to May 24 had no statistical significance (P>0.05). Our local autocorrelation analysis showed that 22 high-high clustering areas were detected in eight periods.The high-risk hot-spot areas have experienced a "less-more-less" change process. The growth model fitting results were consistent with the actual infection situation. Conclusion: There was a clear spatiotemporal correlation in the distribution of COVID-19 in Shanghai. The comprehensive prevention and control measures of COVID-19 epidemic in Shanghai have effectively prohibited the growth of the epidemic, not only curbing the spatially spread of high-risk epidemic areas, but also reducing the risk of transmission to other cities.

An Improved Lightweight YOLOv5 Model Based on Attention Mechanism for Face Mask Detection

Coronavirus 2019 has brought severe challenges to social stability and public health worldwide. One effective way of curbing the epidemic is to require people to wear masks in public places and monitor their mask-wearing states by suitable automatic detectors. However, existing models struggle to simultaneously achieve the requirements of both high precision and real-time performance. To solve this problem, we propose an improved lightweight face mask detector based on YOLOv5, which can achieve an excellent balance of precision and speed. Firstly, a novel backbone ShuffleCANet that combines ShuffleNetV2 network with Coordinate Attention mechanism is proposed as the backbone. Afterward, an efficient path aggression network BiFPN is applied as the feature fusion neck. Furthermore, the localization loss is replaced with alpha-CIoU in model training phase to obtain higher-quality anchors. Some valuable strategies such as data augmentation, adaptive image scaling, and anchor cluster operation are also utilized. Experimental results on AIZOO face mask dataset show the superiority of the proposed model. Compared with the original YOLOv5, the proposed model increases the inference speed by 28.3% while still improving the precision by 0.58%. It achieves the best mean average precision of 95.2% compared with other seven existing models, which is 4.4% higher than the baseline.

[Bioactive compounds of Jingfang Granules against SARS-CoV-2 virus proteases 3CL(pro) and PL(pro)]

OBJECTIVE: Jingfang Granules have been recommended for the prevention and treatment of corona virus disease 2019 (COVID-19). Through chemical analysis and bioactivity evaluation, this study aims to elucidate the potential effective components of Jingfang Granules. METHODS: The inhibitory acti-vities of Jingfang Granules extract against 3-chymotrypsin-like protease (3CL(pro)), papain like protease (PL(pro)), spike protein receptor-binding domain (S-RBD) and human cyclooxygenase-2 (COX-2) were evaluated using enzyme assay. The antitussive effects were evaluated using the classical ammonia-induced cough model. The chemical constituents of Jingfang Granules were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry (LC/MS). The 3CL(pro) and PL(pro) inhibitory activities of the major compounds were determined by enzyme assay, molecular docking, and site-directed mutagenesis. RESULTS: Jingfang Granules exhibited 3CL(pro) and PL(pro) inhibitory activities, as well as COX-2 inhibitory and antitussive activities. By investigating the MS/MS behaviors of reference standards, a total of fifty-six compounds were characterized in Jingfang Granules. Sixteen of them were unambiguously identified by comparing with reference standards. The contents of the 16 major compounds were also determined, and their total contents were 2 498.8 μg/g. Naringin, nodakenin and neohesperidin were three dominating compounds in Jingfang Granules, and their contents were 688.8, 596.4 and 578.7 μg/g, respectively. In addition, neohesperidin and naringin exhibited PL(pro) inhibitory activities, and the inhibition rates at 8 μmol/L were 53.5% and 46.1%, respectively. Prim-O-glucosylcimifugin showed significant inhibitory activities against 3CL(pro) and PL(pro), and the inhibitory rates at 8 μmol/L were 76.8% and 78.2%, respectively. Molecular docking indicated that hydrogen bonds could be formed between prim-O-glucosylcimifugin and amino acid residues H163, E166, Q192, T190 of 3CL(pro) (binding energy, -7.7 kcal/mol) and K157, D164, R166, E167, T301 of PL(pro)(-7.3 kcal/mol), respectively. Site-directed mutagenesis indicated amino acid residue K157 was a key active site for the interaction between prim-O-glucosylcimifugin and PL(pro). CONCLUSION: Prim-O-glucosylcimifugin, neohesperidin, and naringin as the major compounds from Jingfang Granules could inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus proteases 3CL(pro) and PL(pro). The results are valuable for rational clinical use of Jingfang Granules.

Optimization of SARS-CoV-2 spike protein receptor binding domain expression in Pichia pastoris and evaluation of its immunogenicity

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 × 106 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. © 2022 Society of Microbiology and Immunology. All rights reserved.