RESUMO
Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2 infection and was first reported in central China in December 2019. Extensive molecular surveillance in Guangdong, China's most populous province, during early 2020 resulted in 1,388 reported RNA-positive cases from 1.6 million tests. In order to understand the molecular epidemiology and genetic diversity of SARS-CoV-2 in China, we generated 53 genomes from infected individuals in Guangdong using a combination of metagenomic sequencing and tiling amplicon approaches. Combined epidemiological and phylogenetic analyses indicate multiple independent introductions to Guangdong, although phylogenetic clustering is uncertain because of low virus genetic variation early in the pandemic. Our results illustrate how the timing, size, and duration of putative local transmission chains were constrained by national travel restrictions and by the province's large-scale intensive surveillance and intervention measures. Despite these successes, COVID-19 surveillance in Guangdong is still required, because the number of cases imported from other countries has increased.
Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/epidemiologia , Pneumonia Viral/epidemiologia , Teorema de Bayes , COVID-19 , China/epidemiologia , Infecções por Coronavirus/virologia , Monitoramento Epidemiológico , Humanos , Funções Verossimilhança , Pandemias , Pneumonia Viral/virologia , SARS-CoV-2 , ViagemRESUMO
Despite the rapid deployment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, the emergence of SARS-CoV-2 variants and reports of their immune evasion characteristics have led to an urgent need for novel vaccines that confer potent cross-protective immunity. In this study, we constructed three different SARS-CoV-2 spike S1-conjugated nanoparticle vaccine candidates that exhibited high structural homogeneity and stability. Notably, these vaccines elicited up to 50-times-higher neutralizing antibody titers than the S1 monomer in mice. Crucially, it was found that the S1-conjugated nanoparticle vaccine could elicit comparable levels of neutralizing antibodies against wild-type or emerging variant SARS-CoV-2, with cross-reactivity to SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV), the effect of which could be further enhanced using our designed nanoparticles. Our results indicate that the S1-conjugated nanoparticles are promising vaccine candidates with the potential to elicit potent and cross-reactive immunity against not only wild-type SARS-CoV-2, but also its variants of concern, variants of interest, and even other pathogenic betacoronaviruses. IMPORTANCE The emergence of SARS-CoV-2 variants led to an urgent demand for a broadly effective vaccine against the threat of variant infection. The spike protein S1-based nanoparticle designed in our study could elicit a comprehensive humoral response toward different SARS-CoV-2 variants of concern and variants of interest and will be helpful to combat COVID-19 globally.
Assuntos
Formação de Anticorpos , Vacinas contra COVID-19 , COVID-19 , Nanopartículas , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Formação de Anticorpos/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Humanos , Camundongos , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus first identified in December 2019. Notable features that make SARS-CoV-2 distinct from most other previously identified betacoronaviruses include a receptor binding domain and a unique insertion of 12 nucleotides or 4 amino acids (PRRA) at the S1/S2 boundary. In this study, we identified two deletion variants of SARS-CoV-2 that either directly affect the polybasic cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN). These deletions were verified by multiple sequencing methods. In vitro results showed that the deletion of NSPRRAR likely does not affect virus replication in Vero and Vero-E6 cells; however, the deletion of QTQTN may restrict late-phase viral replication. The deletion of QTQTN was detected in 3 of 68 clinical samples and 12 of 24 in vitro-isolated viruses, while the deletion of NSPRRAR was identified in 3 in vitro-isolated viruses. Our data indicate that (i) there may be distinct selection pressures on SARS-CoV-2 replication or infection in vitro and in vivo; (ii) an efficient mechanism for deleting this region from the viral genome may exist, given that the deletion variant is commonly detected after two rounds of cell passage; and (iii) the PRRA insertion, which is unique to SARS-CoV-2, is not fixed during virus replication in vitro These findings provide information to aid further investigation of SARS-CoV-2 infection mechanisms and a better understanding of the NSPRRAR deletion variant observed here.IMPORTANCE The spike protein determines the infectivity and host range of coronaviruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has two unique features in its spike protein, the receptor binding domain and an insertion of 12 nucleotides at the S1/S2 boundary resulting in a furin-like cleavage site. Here, we identified two deletion variants of SARS-CoV-2 that either directly affect the furin-like cleavage site itself (NSPRRAR) or a flanking sequence (QTQTN), and we investigated these deletions in cell isolates and clinical samples. The absence of the polybasic cleavage site in SARS-CoV-2 did not affect virus replication in Vero or Vero-E6 cells. Our data indicate the PRRAR sequence and the flanking QTQTN sequence are not fixed in vitro; thus, there appears to be distinct selection pressures on SARS-CoV-2 sequences in vitro and in vivo Further investigation of the mechanism of generating these deletion variants and their infectivity in different animal models would improve our understanding of the origin and evolution of this virus.
Assuntos
Betacoronavirus/genética , Betacoronavirus/metabolismo , Deleção de Sequência , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/isolamento & purificação , Sequência de Aminoácidos , Animais , Sequência de Bases , COVID-19 , Linhagem Celular , Chlorocebus aethiops , Infecções por Coronavirus/virologia , Furina/metabolismo , Genoma Viral , Especificidade de Hospedeiro , Cinética , Modelos Moleculares , Pandemias , Pneumonia Viral/virologia , Conformação Proteica , SARS-CoV-2 , Análise de Sequência , Glicoproteína da Espícula de Coronavírus/química , Células Vero , Replicação ViralRESUMO
We prospectively assessed 49 coronavirus disease cases in Guangdong, China, to estimate the frequency and duration of detectable severe acute respiratory syndrome coronavirus 2 RNA in human body fluids. The prolonged persistence of virus RNA in various body fluids may guide the clinical diagnosis and prevention of onward virus transmission.
Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/transmissão , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/transmissão , RNA Viral/genética , Adolescente , Adulto , Idoso , Betacoronavirus/genética , COVID-19 , Teste para COVID-19 , Criança , Pré-Escolar , China/epidemiologia , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Fezes/virologia , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Nasofaringe/virologia , Faringe/virologia , Pneumonia Viral/diagnóstico , Estudos Prospectivos , Reação em Cadeia da Polimerase em Tempo Real , SARS-CoV-2 , Índice de Gravidade de Doença , Escarro/virologia , Fatores de TempoRESUMO
Market surveillance showed continuing circulation of avian influenza A(H5N6) virus in live poultry markets in Guangdong Province in 2017, despite compulsory vaccination for avian influenza A(H5Nx) and A(H7N9). We analyzed H5N6 viruses from 2014-2018 from Guangdong Province, revealing antigenic drift and decreased antibody response against the vaccine strain in vaccinated chickens.
Assuntos
Antígenos Virais/genética , Vírus da Influenza A/imunologia , Influenza Aviária/imunologia , Doenças das Aves Domésticas/virologia , Animais , Antígenos Virais/imunologia , Galinhas/virologia , China/epidemiologia , Deriva Genética , Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Influenza Aviária/genética , Influenza Aviária/virologia , Filogenia , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/imunologia , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterináriaRESUMO
BACKGROUND: Newcastle disease (ND) is an OIE listed disease caused by virulent avian paramyxovirus type 1 (APMV-1) strains, which is enzootic and causes large economic losses in the poultry sector. Genotype VII and genotype IX NDV viruses were the predominant circulating genotype in China, which may possibly be responsible for disease outbreaks in chicken flocks in recent years. While ducks and geese usually have exhibited inapparent infections. METHODS: In the present study, we investigate the complete genome sequence, the clinicopathological characterization and transmission of two virulent Newcastle disease viruses, SS-10 and NH-10, isolated from domestic ducks in Southern China in 2010. RESULTS: F, and the complete gene sequences based on phylogenetic analysis demonstrated that SS-10 (genotype VII) and NH-10 (genotype IX) belongs to class II. The deduced amino acid sequence was (112)R-R-Q-K/R-R-F(117) at the fusion protein cleavage site. Animal experiment results showed that the SS-10 virus isolated from ducks was highly pathogenic for chickens and geese, but low pathogenic for ducks. It could be detected from spleen, lung, kidney, trachea, small intestine, bursa of fabricius, thymus, pancreas and cecal tonsils, oropharyngeal and cloacal swabs, and could transmit to the naive contact birds. Moreover, it could transmit to chickens, ducks and geese by naive contact. However, the NH-10 virus isolated from ducks could infect some chickens, ducks and geese, but only caused chickens to die. Additionally, it could transmit to the naive contact chickens, ducks, and geese. CONCLUSION: The two NDV isolates exhibited different biological properties with respect to pathogenicity and transmission in chickens, ducks and geese. Therefore, no species-preference exists for chicken, duck or goose viruses and more attention should be paid to the trans-species transmission of VII NDVs between ducks, geese and chickens for the control and eradication of ND.
Assuntos
Patos/virologia , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/classificação , Vírus da Doença de Newcastle/genética , Doenças das Aves Domésticas/virologia , Animais , Galinhas , China , Surtos de Doenças , Gansos , Genoma Viral , Dados de Sequência Molecular , Doença de Newcastle/transmissão , Vírus da Doença de Newcastle/patogenicidade , Fases de Leitura Aberta , Doenças das Aves Domésticas/transmissão , RNA Viral , Análise de Sequência de DNA , Virulência/genéticaRESUMO
Melanoma differentiation-associated gene 5 (MDA5) is an important intracellular receptor that recognizes long molecules of viral double-stranded RNA in innate immunity. To understand the mechanism of duck MDA5-mediated innate immunity, we cloned the MDA5 cDNA from the Muscovy duck (Cairina moschata). Quantitative real-time PCR analysis indicates that duck MDA5 mRNA was constitutively expressed in all sampled tissues. A significant increase of MDA5 mRNA was detected in the brain, spleen and lungs of ducks after infection with an H5N1 highly pathogenic avian influenza virus (HPAIV). We investigated the role of the predicted functional domains of MDA5. The results indicate the caspase activation and recruitment domain (CARD) of duck MDA5 had a signal transmission function through IRF-7-dependent signaling pathway. Overexpression of the CARD strongly activated the chicken IFN-ß promoter and upregulated the mRNA expression of antiviral molecules (such as OAS, PKR and Mx), proinflammatory cytokines (such as IL-2, IL-6, IFN-α and IFN-γ, but not IL-1ß and IL-8) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLR) (RIG-I and LGP2) without exogenous stimulation. We also demonstrate the NS1 of the H5N1 HPAIV inhibited the duck MDA5-mediated signaling pathway in vitro. These results suggest that duck MDA5 is an important receptor for inducing antiviral activity in the host immune response of ducks.
Assuntos
Proteínas Aviárias/genética , Patos , Virus da Influenza A Subtipo H5N1/imunologia , Influenza Aviária/imunologia , Doenças das Aves Domésticas/imunologia , Transdução de Sinais , Proteínas não Estruturais Virais/genética , Sequência de Aminoácidos , Animais , Proteínas Aviárias/química , Proteínas Aviárias/metabolismo , Clonagem Molecular , DNA Complementar/genética , DNA Complementar/metabolismo , Fibroblastos/fisiologia , Fibroblastos/virologia , Imunidade Inata , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/genética , Influenza Aviária/virologia , Dados de Sequência Molecular , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/virologia , Alinhamento de Sequência/veterinária , Proteínas não Estruturais Virais/metabolismoRESUMO
Global COVID-19 vaccination programs effectively contained the fast spread of SARS-CoV-2. Characterizing the immunity status of returned populations will favor understanding the achievement of herd immunity and long-term management of COVID-19 in China. Individuals were recruited from 7 quarantine stations in Guangzhou, China. Blood and throat swab specimens were collected from participants, and their immunity status was determined through competitive ELISA, microneutralization assay and enzyme-linked FluoroSpot assay. A total of 272 subjects were involved in the questionnaire survey, of whom 235 (86.4%) were returning Chinese individuals and 37 (13.6%) were foreigners. Blood and throat swab specimens were collected from 108 returning Chinese individuals. Neutralizing antibodies against SARS-CoV-2 were detected in ~90% of returning Chinese individuals, either in the primary or the homologous and heterologous booster vaccination group. The serum NAb titers were significantly decreased against SARS-CoV-2 Omicron BA.5, BF.7, BQ.1 and XBB.1 compared with the prototype virus. However, memory T-cell responses, including specific IFN-γ and IL-2 responses, were not different in either group. Smoking, alcohol consumption, SARS-CoV-2 infection, COVID-19 vaccination, and the time interval between last vaccination and sampling were independent influencing factors for NAb titers against prototype SARS-CoV-2 and variants of concern. The vaccine dose was the unique common influencing factor for Omicron subvariants. Enhanced immunity against SARS-CoV-2 was established in returning Chinese individuals who were exposed to reinfection and vaccination. Domestic residents will benefit from booster homologous or heterologous COVID-19 vaccination after reopening of China, which is also useful against breakthrough infection.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Anticorpos Neutralizantes , China/epidemiologiaRESUMO
We report here the complete genomic sequence of an H7N3 avian influenza virus (AIV) isolate, which was obtained from duck in 1996. This is the first report of this subtype of AIV being isolated from duck in Guangdong of Southern China. Genomic sequence and phylogenetic analyses showed that it was highly homologous with the wild bird virus A/ruddy turnstone/Delaware Bay/135/1996 (H7N3) and that all eight genes of this virus belonged to the North America gene pool. The availability of genome sequences is helpful to further investigations of epidemiology and evolution of AIV between waterfowl and wild birds.
Assuntos
Patos/virologia , Genoma Viral , Vírus da Influenza A Subtipo H7N3/genética , Influenza Aviária/virologia , Animais , Sequência de Bases , China , Vírus da Influenza A Subtipo H7N3/isolamento & purificação , Dados de Sequência Molecular , Filogenia , Análise de Sequência de RNARESUMO
An H5N1 avian influenza virus (AIV) designated A/Parrot/Guangdong/C99/2005 (H5N1) was first isolated from a sick parrot in Guangdong in southern China in 2005. The complete genome of this strain was analyzed. Genome sequence analysis showed that all 8 gene segments of the virus nucleotide had 99.0% homology to A/chicken/Henan/12/2004 (H5N1). Phylogenetic analysis demonstrated that all 8 gene segments of the virus were derived from the Eurasian lineage. The availability of genome sequences is useful to investigate the host range and genetic evolution of the H5N1 avian influenza virus in Southern China.
Assuntos
Genoma Viral , Virus da Influenza A Subtipo H5N1/genética , RNA Viral/genética , Análise de Sequência de DNA , Animais , China , Análise por Conglomerados , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/virologia , Dados de Sequência Molecular , Papagaios , Filogenia , Homologia de Sequência do Ácido NucleicoRESUMO
In this study, we report the first genomic information on an H5N1 avian influenza virus (AIV) isolated from a condor in Guangdong Province in southern China in 2003. Full genome sequencing and phylogenetic analyses show that it is a recombinant virus containing genome segments derived from the Eurasia and North America gene pools. This will be useful for analyses of the evolution of H5N1 AIV in southern China.
Assuntos
Falconiformes/virologia , Genoma Viral , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/virologia , Animais , Sequência de Bases , China , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Dados de Sequência Molecular , Neuraminidase/genética , Filogenia , Análise de Sequência de RNARESUMO
We report the complete genome sequence of an H5N2 avian influenza virus (AIV) that was first isolated from a parrot in Guangdong in southern China in 2004. Genomic sequence and phylogenetic analyses showed that it was highly homologous with the North American H5N2 viruses and all eight genes of this virus belonged to the North American gene lineage. These data will help in the investigation of the epidemiology and host range of AIVs in southern China.
Assuntos
Genoma Viral , Vírus da Influenza A Subtipo H5N2/genética , RNA Viral/genética , Análise de Sequência de DNA , Animais , China , Análise por Conglomerados , Vírus da Influenza A Subtipo H5N2/isolamento & purificação , Influenza Aviária/virologia , Epidemiologia Molecular , Dados de Sequência Molecular , Papagaios , FilogeniaRESUMO
An H10N8 avian influenza virus (AIV), designated A/Duck/Guangdong/E1/2012 (H10N8), was isolated from a duck in January 2012. This is first report that this subtype of AIV was isolated from a live bird market (LBM) in Guangdong Province in southern China. Furthermore, the complete genome of this strain was analyzed. The availability of genome sequences is helpful to further investigations of epidemiology and molecular characteristics of AIV in southern China.
Assuntos
Patos/virologia , Genoma Viral , Vírus da Influenza A/genética , Animais , Sequência de Bases , China , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/virologia , Dados de Sequência Molecular , Neuraminidase/genética , Fases de Leitura Aberta/genética , Análise de Sequência de RNARESUMO
Here, we reported the complete genome sequence of a novel H6N2 avian influenza virus (AIV) isolated from chicken in Guangdong, Southern China, in 2011 which was a natural recombinant virus between the H6N2 and H5N1 subtypes. It will help to understand the epidemiology and molecular characteristics of H6N2 influenza virus in Southern China.
Assuntos
Galinhas/virologia , Genoma Viral , Vírus da Influenza A/genética , Animais , Sequência de Bases , China , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Influenza Aviária/virologia , Dados de Sequência Molecular , Neuraminidase/classificação , Neuraminidase/genética , Filogenia , Recombinação Genética , Análise de Sequência de RNARESUMO
Waterfowl, such as ducks, are natural hosts for avian influenza viruses (AIVs) and act as a bridge for transmitting the virus to humans or susceptible chickens. Since 2013, chickens and ducks have been threatened by waterfowl-origin H5N6 subtype AIVs in China. Therefore, it is necessary to investigate the genetic evolution, transmission, and pathogenicity of these viruses. In this study, we determined the genetic characteristics, transmission, and pathogenicity of waterfowl-origin H5N6 viruses in southern China. The hemagglutinin (HA) genes of H5N6 viruses were classified into the MIX-like branch of clade 2.3.4.4h. The neuraminidase (NA) genes belonged to the Eurasian lineage. The PB1 genes were classified into MIX-like and VN 2014-like branches. The remaining five genes were clustered into the MIX-like branch. Therefore, these viruses belonged to different genotypes. The cleavage site of the HA proteins of these viruses was RERRRKR/G, a molecular characteristic of the H5 highly pathogenic AIV. The NA stalk of all H5N6 viruses contained 11 amino acid deletions at residues 58-68. All viruses contained 627E and 701D in the PB2 proteins, which were molecular characteristics of typical bird AIVs. Furthermore, this study showed that Q135 and S23 viruses could replicate systematically in chickens and ducks. They did not cause death in ducks but induced mild clinical signs in them. All the infected chickens showed severe clinical signs and died. These viruses were shed from the digestive and respiratory tracts and transmitted horizontally in chickens and ducks. Our results provide valuable information for preventing H5N6 avian influenza outbreaks.
RESUMO
Emerging SARS-CoV-2 variants of concern (VOCs) harboring multiple mutations in the spike protein raise concerns on effectiveness of current vaccines that rely on the ancestral spike protein. Here, we design a quadrivalent mosaic nanoparticle vaccine displaying spike proteins from the SARS-CoV-2 prototype and 3 different VOCs. The mosaic nanoparticle elicits equivalent or superior neutralizing antibodies against variant strains in mice and non-human primates with only small reduction in neutralization titers against the ancestral strain. Notably, it provides protection against infection with prototype and B.1.351 strains in mice. These results provide a proof of principle for the development of multivalent vaccines against pandemic and potential pre-emergent SARS-CoV-2 variants.
Assuntos
COVID-19 , Nanopartículas , Animais , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Camundongos , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , Vacinas CombinadasAssuntos
Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Humana/epidemiologia , Influenza Humana/virologia , Vírus Reordenados , Animais , China/epidemiologia , História do Século XXI , Humanos , Vírus da Influenza A/isolamento & purificação , Influenza Humana/história , Influenza Humana/transmissãoRESUMO
To identify animals susceptible to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection or to determine whether SARS-CoV-2 contaminated meat is from a SARS-CoV-2-infected animal, a convenient and safe method was developed for rapid detection of SARS-CoV-2 in a replicating or non-replicating status in samples using reverse transcriptase-polymerase chain reaction (RT-PCR). This strategy can also be applied to develop assays for the detection of other viruses, either replicating or not.
Assuntos
Teste para COVID-19/métodos , COVID-19/diagnóstico , RNA Viral/análise , Reação em Cadeia da Polimerase Via Transcriptase Reversa , SARS-CoV-2/fisiologia , Replicação Viral , Animais , Humanos , Sensibilidade e EspecificidadeRESUMO
The appearance and magnitude of the immune response and the related factors correlated with SARS-CoV-2 vaccination need to be defined. Here, we enrolled a prospective cohort of 52 participants who received two doses of inactivated vaccines (BBIBP-CorV). Their serial plasma samples (n = 260) over 2 months were collected at five timepoints. We measured antibody responses (NAb, S-IgG and S-IgM) and routine blood parameter. NAb seroconversion occurred in 90.7% of vaccinated individuals and four typical NAb kinetic curves were observed. All of the participants who seroconverted after the first dose were females and had relatively high prevaccine estradiol levels. Moreover, those without seroconversion tended to have lower lymphocyte counts and higher serum SAA levels than those who experienced seroconversion. The NAb titers in young vaccine recipients had a significantly higher peak than those in elderly recipients. S-IgG and S-IgM dynamics were accompanied by similar trends in NAb. Here, we gained insight into the dynamic changes in NAbs and preliminarily explored the prevaccine blood parameters related to the kinetic subclasses, providing a reference for vaccination strategies.
Assuntos
Vacinas contra COVID-19 , COVID-19 , Idoso , Anticorpos Neutralizantes , Anticorpos Antivirais , Formação de Anticorpos , Feminino , Voluntários Saudáveis , Humanos , Estudos Prospectivos , SARS-CoV-2 , Vacinas de Produtos InativadosRESUMO
The coronavirus disease pandemic of 2019 (COVID-19) caused by the novel SARS-CoV-2 coronavirus resulted in economic losses and threatened human health worldwide. The pandemic highlights an urgent need for a stable, easily produced, and effective vaccine. SARS-CoV-2 uses the spike protein receptor-binding domain (RBD) to bind its cognate receptor, angiotensin-converting enzyme 2 (ACE2), and initiate membrane fusion. Thus, the RBD is an ideal target for vaccine development. In this study, we designed three different RBD-conjugated nanoparticle vaccine candidates, namely, RBD-Ferritin (24-mer), RBD-mi3 (60-mer), and RBD-I53-50 (120-mer), via covalent conjugation using the SpyTag-SpyCatcher system. When mice were immunized with the RBD-conjugated nanoparticles (NPs) in conjunction with the AddaVax or Sigma Adjuvant System, the resulting antisera exhibited 8- to 120-fold greater neutralizing activity against both a pseudovirus and the authentic virus than those of mice immunized with monomeric RBD. Most importantly, sera from mice immunized with RBD-conjugated NPs more efficiently blocked the binding of RBD to ACE2 in vitro, further corroborating the promising immunization effect. Additionally, the vaccine has distinct advantages in terms of a relatively simple scale-up and flexible assembly. These results illustrate that the SARS-CoV-2 RBD-conjugated nanoparticles developed in this study are a competitive vaccine candidate and that the carrier nanoparticles could be adopted as a universal platform for a future vaccine development.