RESUMO
BA.2.86, a recently identified descendant of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.2 sublineage, contains â¼35 mutations in the spike (S) protein and spreads in multiple countries. Here, we investigated whether the virus exhibits altered biological traits, focusing on S protein-driven viral entry. Employing pseudotyped particles, we show that BA.2.86, unlike other Omicron sublineages, enters Calu-3 lung cells with high efficiency and in a serine- but not cysteine-protease-dependent manner. Robust lung cell infection was confirmed with authentic BA.2.86, but the virus exhibited low specific infectivity. Further, BA.2.86 was highly resistant against all therapeutic antibodies tested, efficiently evading neutralization by antibodies induced by non-adapted vaccines. In contrast, BA.2.86 and the currently circulating EG.5.1 sublineage were appreciably neutralized by antibodies induced by the XBB.1.5-adapted vaccine. Collectively, BA.2.86 has regained a trait characteristic of early SARS-CoV-2 lineages, robust lung cell entry, and evades neutralizing antibodies. However, BA.2.86 exhibits low specific infectivity, which might limit transmissibility.
Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19 , SARS-CoV-2 , Humanos , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Caspases/metabolismo , COVID-19/imunologia , COVID-19/virologia , Pulmão/virologia , SARS-CoV-2/classificação , SARS-CoV-2/genética , SARS-CoV-2/patogenicidade , SARS-CoV-2/fisiologia , Internalização do Vírus , Glicoproteína da Espícula de Coronavírus/genéticaRESUMO
Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is initiated by binding of the viral Spike protein to host receptor angiotensin-converting enzyme 2 (ACE2), followed by fusion of viral and host membranes. Although antibodies that block this interaction are in emergency use as early coronavirus disease 2019 (COVID-19) therapies, the precise determinants of neutralization potency remain unknown. We discovered a series of antibodies that potently block ACE2 binding but exhibit divergent neutralization efficacy against the live virus. Strikingly, these neutralizing antibodies can inhibit or enhance Spike-mediated membrane fusion and formation of syncytia, which are associated with chronic tissue damage in individuals with COVID-19. As revealed by cryoelectron microscopy, multiple structures of Spike-antibody complexes have distinct binding modes that not only block ACE2 binding but also alter the Spike protein conformational cycle triggered by ACE2 binding. We show that stabilization of different Spike conformations leads to modulation of Spike-mediated membrane fusion with profound implications for COVID-19 pathology and immunity.
Assuntos
Anticorpos Neutralizantes/química , Células Gigantes/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/imunologia , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/metabolismo , Complexo Antígeno-Anticorpo/química , Complexo Antígeno-Anticorpo/metabolismo , Sítios de Ligação , Células CHO , COVID-19/patologia , COVID-19/virologia , Cricetinae , Cricetulus , Microscopia Crioeletrônica , Células Gigantes/citologia , Humanos , Fusão de Membrana , Biblioteca de Peptídeos , Ligação Proteica , Domínios Proteicos , Estrutura Quaternária de Proteína , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
Despite the discovery of animal coronaviruses related to SARS-CoV-2, the evolutionary origins of this virus are elusive. We describe a meta-transcriptomic study of 411 bat samples collected from a small geographical region in Yunnan province, China, between May 2019 and November 2020. We identified 24 full-length coronavirus genomes, including four novel SARS-CoV-2-related and three SARS-CoV-related viruses. Rhinolophus pusillus virus RpYN06 was the closest relative of SARS-CoV-2 in most of the genome, although it possessed a more divergent spike gene. The other three SARS-CoV-2-related coronaviruses carried a genetically distinct spike gene that could weakly bind to the hACE2 receptor in vitro. Ecological modeling predicted the co-existence of up to 23 Rhinolophus bat species, with the largest contiguous hotspots extending from South Laos and Vietnam to southern China. Our study highlights the remarkable diversity of bat coronaviruses at the local scale, including close relatives of both SARS-CoV-2 and SARS-CoV.
Assuntos
COVID-19/virologia , Quirópteros/virologia , Coronavirus/genética , Evolução Molecular , SARS-CoV-2/genética , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Sudeste Asiático , China , Coronavirus/classificação , Coronavirus/isolamento & purificação , Fenômenos Ecológicos e Ambientais , Genoma Viral , Humanos , Modelos Moleculares , Filogenia , SARS-CoV-2/fisiologia , Alinhamento de Sequência , Análise de Sequência de RNA , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Zoonoses ViraisRESUMO
Memory B cells play a fundamental role in host defenses against viruses, but to date, their role has been relatively unsettled in the context of SARS-CoV-2. We report here a longitudinal single-cell and repertoire profiling of the B cell response up to 6 months in mild and severe COVID-19 patients. Distinct SARS-CoV-2 spike-specific activated B cell clones fueled an early antibody-secreting cell burst as well as a durable synchronous germinal center response. While highly mutated memory B cells, including pre-existing cross-reactive seasonal Betacoronavirus-specific clones, were recruited early in the response, neutralizing SARS-CoV-2 RBD-specific clones accumulated with time and largely contributed to the late, remarkably stable, memory B cell pool. Highlighting germinal center maturation, these cells displayed clear accumulation of somatic mutations in their variable region genes over time. Overall, these findings demonstrate that an antigen-driven activation persisted and matured up to 6 months after SARS-CoV-2 infection and may provide long-term protection.
Assuntos
Linfócitos B/imunologia , COVID-19/imunologia , Memória Imunológica , Adulto , COVID-19/fisiopatologia , Citometria de Fluxo , Centro Germinativo/citologia , Humanos , Ativação Linfocitária , Pessoa de Meia-Idade , Índice de Gravidade de Doença , Análise de Célula Única , Glicoproteína da Espícula de Coronavírus/químicaRESUMO
The global spread of SARS-CoV-2/COVID-19 is devastating health systems and economies worldwide. Recombinant or vaccine-induced neutralizing antibodies are used to combat the COVID-19 pandemic. However, the recently emerged SARS-CoV-2 variants B.1.1.7 (UK), B.1.351 (South Africa), and P.1 (Brazil) harbor mutations in the viral spike (S) protein that may alter virus-host cell interactions and confer resistance to inhibitors and antibodies. Here, using pseudoparticles, we show that entry of all variants into human cells is susceptible to blockade by the entry inhibitors soluble ACE2, Camostat, EK-1, and EK-1-C4. In contrast, entry of the B.1.351 and P.1 variant was partially (Casirivimab) or fully (Bamlanivimab) resistant to antibodies used for COVID-19 treatment. Moreover, entry of these variants was less efficiently inhibited by plasma from convalescent COVID-19 patients and sera from BNT162b2-vaccinated individuals. These results suggest that SARS-CoV-2 may escape neutralizing antibody responses, which has important implications for efforts to contain the pandemic.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , SARS-CoV-2/imunologia , Animais , COVID-19/imunologia , COVID-19/terapia , COVID-19/virologia , Linhagem Celular , Farmacorresistência Viral , Humanos , Imunização Passiva , Cinética , Fusão de Membrana , Modelos Moleculares , Testes de Neutralização , Serina Endopeptidases/metabolismo , Solubilidade , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinação , Internalização do Vírus , Soroterapia para COVID-19RESUMO
We identified an emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant by viral whole-genome sequencing of 2,172 nasal/nasopharyngeal swab samples from 44 counties in California, a state in the western United States. Named B.1.427/B.1.429 to denote its two lineages, the variant emerged in May 2020 and increased from 0% to >50% of sequenced cases from September 2020 to January 2021, showing 18.6%-24% increased transmissibility relative to wild-type circulating strains. The variant carries three mutations in the spike protein, including an L452R substitution. We found 2-fold increased B.1.427/B.1.429 viral shedding in vivo and increased L452R pseudovirus infection of cell cultures and lung organoids, albeit decreased relative to pseudoviruses carrying the N501Y mutation common to variants B.1.1.7, B.1.351, and P.1. Antibody neutralization assays revealed 4.0- to 6.7-fold and 2.0-fold decreases in neutralizing titers from convalescent patients and vaccine recipients, respectively. The increased prevalence of a more transmissible variant in California exhibiting decreased antibody neutralization warrants further investigation.
Assuntos
Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/transmissão , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Humanos , Mutação/genética , Sequenciamento Completo do Genoma/métodosRESUMO
The SARS-CoV-2 spike (S) protein variant D614G supplanted the ancestral virus worldwide, reaching near fixation in a matter of months. Here we show that D614G was more infectious than the ancestral form on human lung cells, colon cells, and on cells rendered permissive by ectopic expression of human ACE2 or of ACE2 orthologs from various mammals, including Chinese rufous horseshoe bat and Malayan pangolin. D614G did not alter S protein synthesis, processing, or incorporation into SARS-CoV-2 particles, but D614G affinity for ACE2 was reduced due to a faster dissociation rate. Assessment of the S protein trimer by cryo-electron microscopy showed that D614G disrupts an interprotomer contact and that the conformation is shifted toward an ACE2 binding-competent state, which is modeled to be on pathway for virion membrane fusion with target cells. Consistent with this more open conformation, neutralization potency of antibodies targeting the S protein receptor-binding domain was not attenuated.
Assuntos
Betacoronavirus/fisiologia , Betacoronavirus/ultraestrutura , Glicoproteína da Espícula de Coronavírus/fisiologia , Glicoproteína da Espícula de Coronavírus/ultraestrutura , Enzima de Conversão de Angiotensina 2 , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Betacoronavirus/patogenicidade , COVID-19 , Células Cultivadas , Infecções por Coronavirus/virologia , Feminino , Variação Genética , Células HEK293 , Humanos , Masculino , Modelos Moleculares , Pandemias , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/virologia , Conformação Proteica , Processamento de Proteína Pós-Traducional , Receptores de Coronavírus , Receptores Virais/metabolismo , SARS-CoV-2 , Especificidade da EspécieRESUMO
The emergence of SARS-CoV-2 antigenic variants with increased transmissibility is a public health threat. Some variants show substantial resistance to neutralization by SARS-CoV-2 infection- or vaccination-induced antibodies. Here, we analyzed receptor binding domain-binding monoclonal antibodies derived from SARS-CoV-2 mRNA vaccine-elicited germinal center B cells for neutralizing activity against the WA1/2020 D614G SARS-CoV-2 strain and variants of concern. Of five monoclonal antibodies that potently neutralized the WA1/2020 D614G strain, all retained neutralizing capacity against the B.1.617.2 variant, four also neutralized the B.1.1.7 variant, and only one, 2C08, also neutralized the B.1.351 and B.1.1.28 variants. 2C08 reduced lung viral load and morbidity in hamsters challenged with the WA1/2020 D614G, B.1.351, or B.1.617.2 strains. Clonal analysis identified 2C08-like public clonotypes among B cells responding to SARS-CoV-2 infection or vaccination in 41 out of 181 individuals. Thus, 2C08-like antibodies can be induced by SARS-CoV-2 vaccines and mitigate resistance by circulating variants of concern.
Assuntos
Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/metabolismo , Linfócitos B/imunologia , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , Centro Germinativo/imunologia , Pulmão/virologia , SARS-CoV-2/fisiologia , Animais , Células Cultivadas , Células Clonais , Cricetinae , Modelos Animais de Doenças , Humanos , Testes de Neutralização , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinação , Carga ViralRESUMO
Developing effective strategies to prevent or treat coronavirus disease 2019 (COVID-19) requires understanding the natural immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We used an unbiased, genome-wide screening technology to determine the precise peptide sequences in SARS-CoV-2 that are recognized by the memory CD8+ T cells of COVID-19 patients. In total, we identified 3-8 epitopes for each of the 6 most prevalent human leukocyte antigen (HLA) types. These epitopes were broadly shared across patients and located in regions of the virus that are not subject to mutational variation. Notably, only 3 of the 29 shared epitopes were located in the spike protein, whereas most epitopes were located in ORF1ab or the nucleocapsid protein. We also found that CD8+ T cells generally do not cross-react with epitopes in the four seasonal coronaviruses that cause the common cold. Overall, these findings can inform development of next-generation vaccines that better recapitulate natural CD8+ T cell immunity to SARS-CoV-2.
Assuntos
Betacoronavirus/imunologia , Linfócitos T CD8-Positivos/imunologia , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Idoso , Betacoronavirus/isolamento & purificação , COVID-19 , Convalescença , Coronavirus/imunologia , Infecções por Coronavirus/diagnóstico , Proteínas do Nucleocapsídeo de Coronavírus , Mapeamento de Epitopos , Epitopos de Linfócito T , Feminino , Humanos , Epitopos Imunodominantes , Memória Imunológica , Masculino , Pessoa de Meia-Idade , Proteínas do Nucleocapsídeo/imunologia , Pandemias , Fosfoproteínas , Pneumonia Viral/diagnóstico , Poliproteínas , SARS-CoV-2 , Proteínas Virais/imunologia , Adulto JovemRESUMO
Antibody responses develop following SARS-CoV-2 infection, but little is known about their epitope specificities, clonality, binding affinities, epitopes, and neutralizing activity. We isolated B cells specific for the SARS-CoV-2 envelope glycoprotein spike (S) from a COVID-19-infected subject 21 days after the onset of clinical disease. 45 S-specific monoclonal antibodies were generated. They had undergone minimal somatic mutation with limited clonal expansion, and three bound the receptor-binding domain (RBD). Two antibodies neutralized SARS-CoV-2. The most potent antibody bound the RBD and prevented binding to the ACE2 receptor, while the other bound outside the RBD. Thus, most anti-S antibodies that were generated in this patient during the first weeks of COVID-19 infection were non-neutralizing and target epitopes outside the RBD. Antibodies that disrupt the SARS-CoV-2 S-ACE2 interaction can potently neutralize the virus without undergoing extensive maturation. Such antibodies have potential preventive and/or therapeutic potential and can serve as templates for vaccine design.
Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Hipermutação Somática de Imunoglobulina/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2 , Anticorpos Monoclonais/imunologia , Linfócitos B/imunologia , Sítios de Ligação , COVID-19 , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Epitopos de Linfócito B/imunologia , Humanos , Pandemias/prevenção & controle , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/imunologia , Pneumonia Viral/prevenção & controle , Ligação Proteica , Receptores Virais/metabolismo , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/metabolismo , Vacinas Virais/imunologiaRESUMO
We conducted a serological study to define correlates of immunity against SARS-CoV-2. Compared to those with mild coronavirus disease 2019 (COVID-19) cases, individuals with severe disease exhibited elevated virus-neutralizing titers and antibodies against the nucleocapsid (N) and the receptor binding domain (RBD) of the spike protein. Age and sex played lesser roles. All cases, including asymptomatic individuals, seroconverted by 2 weeks after PCR confirmation. Spike RBD and S2 and neutralizing antibodies remained detectable through 5-7 months after onset, whereas α-N titers diminished. Testing 5,882 members of the local community revealed only 1 sample with seroreactivity to both RBD and S2 that lacked neutralizing antibodies. This fidelity could not be achieved with either RBD or S2 alone. Thus, inclusion of multiple independent assays improved the accuracy of antibody tests in low-seroprevalence communities and revealed differences in antibody kinetics depending on the antigen. We conclude that neutralizing antibodies are stably produced for at least 5-7 months after SARS-CoV-2 infection.
Assuntos
Betacoronavirus/imunologia , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/imunologia , Imunidade Humoral , Pneumonia Viral/epidemiologia , Pneumonia Viral/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Arizona/epidemiologia , Betacoronavirus/isolamento & purificação , COVID-19 , Teste para COVID-19 , Infecções por Coronavirus/sangue , Infecções por Coronavirus/diagnóstico , Proteínas do Nucleocapsídeo de Coronavírus , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas do Nucleocapsídeo/imunologia , Pandemias , Fosfoproteínas , Pneumonia Viral/sangue , Pneumonia Viral/diagnóstico , Prevalência , Domínios e Motivos de Interação entre Proteínas , SARS-CoV-2 , Estudos Soroepidemiológicos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto JovemRESUMO
Investigating large datasets of biological information by automatic procedures may offer chances of progress in knowledge. Recently, tremendous improvements in structural biology have allowed the number of structures in the Protein Data Bank (PDB) archive to increase rapidly, in particular those for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated proteins. However, their automatic analysis can be hampered by the nonuniform descriptors used by authors in some records of the PDB and PDBx/mmCIF files. In this opinion article we highlight the difficulties encountered in automating the analysis of hundreds of structures, suggesting that further standardization of the description of these molecular entities and of their attributes, generalized to the macromolecular structures contained in the PDB, might generate files more suitable for automatized analyses of a large number of structures.
Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Proteínas/química , Estrutura Molecular , Bases de Dados de Proteínas , Conformação ProteicaRESUMO
The animal origin of SARS-CoV-2 remains elusive, lacking a plausible evolutionary narrative that may account for its emergence. Its spike protein resembles certain segments of BANAL-236 and RaTG13, two bat coronaviruses considered possible progenitors of SARS-CoV-2. Additionally, its spike contains a furin motif, a common feature of rodent coronaviruses. To explore the possible involvement of rodents in the emergence of SARS-CoV-2 spike, we examined the crystal structures of the spike receptor-binding domains (RBDs) of BANAL-236 and RaTG13 each complexed with mouse receptor ACE2. Both RBDs have residues at positions 493 and 498 that align well with two virus-binding hotspots on mouse ACE2. Our biochemical evidence supports that both BANAL-236 and RaTG13 spikes can use mouse ACE2 as their entry receptor. These findings point to a scenario in which these bat coronaviruses may have coinfected rodents, leading to a recombination of their spike genes and a subsequent acquisition of a furin motif in rodents, culminating in the emergence of SARS-CoV-2.
Assuntos
Enzima de Conversão de Angiotensina 2 , Quirópteros , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Animais , Enzima de Conversão de Angiotensina 2/metabolismo , Enzima de Conversão de Angiotensina 2/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Quirópteros/virologia , Camundongos , SARS-CoV-2/metabolismo , SARS-CoV-2/química , Humanos , Receptores Virais/metabolismo , Receptores Virais/química , COVID-19/virologia , COVID-19/metabolismo , Cristalografia por Raios X , Ligação Proteica , Coronavirus/metabolismo , Coronavirus/genética , Modelos MolecularesRESUMO
Single-particle cryoelectron microscopy (cryo-EM), whose full capabilities have been realized only within the past decade, has had a pivotal role in the fight against COVID-19. This is due to the technique's intrinsic power to depict both structural and dynamic features of molecules; in this case, of the spike protein of SARS-CoV-2. By now, numerous cryo-EM studies have furthered our understanding of spike protein-angiotensin-converting enzyme 2 (ACE2) receptor interactions, which has informed the design of effective vaccines, and have enabled the characterization of neutralizing antibody binding sites, which will lead to the design of novel therapeutics as the virus evolves.
Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Anticorpos Neutralizantes/metabolismo , Microscopia Crioeletrônica , Humanos , Ligação Proteica , SARS-CoV-2RESUMO
The spike (S) protein of SARS-CoV-2, which is undergoing rapid evolution, plays crucial roles in viral immune escape, infectivity, and transmissibility. To gain clinical insight, Dadonaite et al. developed a novel deep mutational scanning (DMS) platform for mapping the effects of S protein mutations on immune evasion and viral infectivity.
Assuntos
COVID-19 , Ensaios de Triagem em Larga Escala , Humanos , COVID-19/genética , SARS-CoV-2/genética , Mutação/genética , Evasão da Resposta ImuneRESUMO
Severe acute respiratory syndrome virus 2 (SARS-CoV-2) invades host cells by interacting with receptors/coreceptors, as well as with other cofactors, via its spike (S) protein that further mediates fusion between viral and cellular membranes. The host membrane protein, angiotensin-converting enzyme 2 (ACE2), is the major receptor for SARS-CoV-2 and is a crucial determinant for cross-species transmission. In addition, some auxiliary receptors and cofactors are also involved that expand the host/tissue tropism of SARS-CoV-2. After receptor engagement, specific proteases are required that cleave the S protein and trigger its fusogenic activity. Here we discuss the recent advances in understanding the molecular events during SARS-CoV-2 entry which will contribute to developing vaccines and therapeutics.
Assuntos
COVID-19 , Glicoproteína da Espícula de Coronavírus , Humanos , Ligação Proteica , Receptores Virais/metabolismo , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/metabolismo , Internalização do VírusRESUMO
Coronaviruses (CoVs) are important pathogens for humans and other vertebrates, causing severe respiratory and intestinal infections that have become a threat to public health because of the potential for interspecies transmission between animals and humans. Therefore, the development of safe, effective vaccines remains a top priority for the control of CoV infection. The unique immunological characteristics of vaccines featuring messenger RNA (mRNA) present an advantageous tool for coronavirus vaccine development. Here, we designed two lipid nanoparticle (LNP)-encapsulated mRNA (mRNA-LNP) vaccines: one encoding full-length spike (S) protein and the other encoding the spike ectodomain (Se) from porcine deltacoronavirus (PDCoV). Fourteen days after primary immunization, both mRNA vaccines induced high levels of immunoglobulin G and neutralizing antibodies in mice, with the S vaccine showing better performance than the Se vaccine. Passive immune protection of the S mRNA vaccine in suckling piglets was confirmed by the induction of robust PDCoV-specific humoral and cellular immune responses. The S mRNA vaccine also showed better protective effects than the inactivated vaccine. Our results suggest that the novel PDCoV-S mRNA-LNP vaccine may have the potential to combat PDCoV infection. IMPORTANCE: As an emerging porcine enteropathogenic coronavirus, porcine deltacoronavirus (PDCoV) has the potential for cross-species transmission, attracting extensive attention. Messenger RNA (mRNA) vaccines are a promising option for combating emerging and re-emerging infectious diseases, as evidenced by the demonstrated efficacy of the COVID-19 mRNA vaccine. Here, we first demonstrated that PDCoV-S mRNA-lipid nanoparticle (LNP) vaccines could induce potent humoral and cellular immune responses in mice. An evaluation of passive immune protection of S mRNA vaccines in suckling piglets confirmed that the protective effect of mRNA vaccine was better than that of inactivated vaccine. This study suggests that the PDCoV-S mRNA-LNP vaccine may serve as a potential and novel vaccine candidate for combating PDCoV infection.
RESUMO
Human recombinant ACE2 (hrACE2) has been highly anticipated as a successful COVID-19 treatment; however, its potential to cause cardiac side effects has given rise to many concerns. Here, we developed a cardiotoxicity-eliminated hrACE2 variant, which had four mutation sites within hrACE2 (H345L, H374L, H378L, H505L) and was named as hrACE2-4mu. hrACE2-4mu has a consistent binding affinity with the variant SARS-CoV-2 spike proteins (SPs) and an efficient ability to block SP-induced SARS-CoV-2 entry into cells. In golden hamsters, injection of purified wild-type (WT) hrACE2 rescues the early stages of pneumonia caused by the SPs of the WT, delta, and omicron variants with reduced inflammatory cell infiltration. However, long-term injection of WT hrACE2 induces undesired cardiac fibrosis, as demonstrated by upregulated fibronectin and collagen expression. Our newly developed hrACE2-4mu showed similar protective abilities against a series of coronavirus cell invasions as WT hrACE2, meanwhile it did not cause apparent cardiac side effects. Thus, we generated a cardiotoxicity-eliminated variant of hrACE2 as a pan-inhibitor against coronavirus cell invasion, providing a potential novel strategy for the treatment of COVID-19 and other coronaviruses.
Assuntos
Enzima de Conversão de Angiotensina 2 , COVID-19 , Animais , Cricetinae , Humanos , Enzima de Conversão de Angiotensina 2/genética , Cardiotoxicidade/etiologia , Tratamento Farmacológico da COVID-19 , Coração , MesocricetusRESUMO
The novel coronavirus disease 2019 has stimulated the rapid development of new biological therapeutics to inhibit SARS-CoV-2 infection; however, this remains a challenging task. In a previous study using structural analysis, we revealed that human cyclophilin A inhibits the entry of SARS-CoV-2 into host cells by interfering with the interaction of the receptor-binding domain of the spike protein with angiotensin-converting enzyme 2 on the host cell surface, highlighting its potential for antiviral therapy. For a comprehensive experimental validation, in this study, we verified the antiviral effects of human cyclophilin A against SARS-CoV-2, including its variants, using in vitro assays and experiments on an in vivo mouse model. Human cyclophilin A demonstrated a highly effective antiviral effect, with an 85% survival rate upon SARS-CoV-2 infection. It also reduced viral titers, inflammation in the lungs and brain, and cytokine release in the serum, suggesting a controlled immune response and potentially faster recovery. Overall, our study provides insights into the potential of human cyclophilin A as a therapeutic agent against SARS-CoV-2, which should guide future clinical trials that might provide an additional therapeutic option for patients.
Assuntos
Antivirais , COVID-19 , Ciclofilina A , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Animais , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/imunologia , SARS-CoV-2/efeitos dos fármacos , Humanos , Ciclofilina A/metabolismo , Camundongos , Antivirais/farmacologia , COVID-19/virologia , COVID-19/metabolismo , Ligação Proteica , Tratamento Farmacológico da COVID-19 , Enzima de Conversão de Angiotensina 2/metabolismo , Modelos Animais de Doenças , Células Vero , Chlorocebus aethiops , FemininoRESUMO
Responsible for more than 4.9 million deaths so far, COVID-19, caused by SARS-CoV-2, is instigating devastating effects on the global health care system whose impacts could be longer for the years to come. Acquiring a comprehensive knowledge of host-virus interaction is critical for designing effective vaccines and/or drugs. Understanding the evolution of the virus and the impact of genetic variability on host immune evasion and vaccine efficacy is helpful to design novel strategies to minimize the effects of the emerging variants of concern (VOC). Most vaccines under development and/or in current use target the spike protein owning to its unique function of host receptor binding, relatively conserved nature, potent immunogenicity in inducing neutralizing antibodies, and being a good target of T cell responses. However, emerging SARS-CoV-2 strains are exhibiting variability on the spike protein which could affect the efficacy of vaccines and antibody-based therapies in addition to enhancing viral immune evasion mechanisms. Currently, the degree to which mutations on the spike protein affect immunity and vaccination, and the ability of the current vaccines to confer protection against the emerging variants attracts much attention. This review discusses the implications of SARS-CoV-2 spike protein mutations on immune evasion and vaccine-induced immunity and forward directions which could contribute to future studies focusing on designing effective vaccines and/or immunotherapies to consider viral evolution. Combining vaccines derived from different regions of the spike protein that boost both the humoral and cellular wings of adaptive immunity could be the best options to cope with the emerging VOC.