Receptor-binding domain of SARS-CoV spike protein induces highly potent neutralizing antibodies: implication for developing subunit vaccine.
Ontology highlight
ABSTRACT:
SUBMITTER: He Y
PROVIDER: S-EPMC7092904 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The use of neutralizing antibodies to identify the most effective antigen has been proposed as a strategy to design vaccines capable of eliciting protective B-cell immunity. In this study, we analyzed the human antibody response to cytomegalovirus (human cytomegalovirus, HCMV) infection and found that antibodies to glycoprotein (g)B, a surface glycoprotein that has been developed as a HCMV vaccine, were primarily nonneutralizing. In contrast, most of the antibodies to the complex formed by gH, gL, protein (p)UL128, pUL130, and pUL131 (the gHgLpUL128L pentamer) neutralized HCMV infection with high potency. Based on this analysis, we developed a single polycistronic vector encoding the five pentamer genes separated by "self-cleaving" 2A peptides to generate a stably transfected CHO cell line constitutively secreting high levels of recombinant pentamer that displayed the functional antigenic sites targeted by human neutralizing antibodies. Immunization of mice with the pentamer formulated with different adjuvants elicited HCMV neutralizing antibody titers that persisted to high levels over time and that were a hundred- to thousand-fold higher than those found in individuals that recovered from primary HCMV infection. Sera from mice immunized with the pentamer vaccine neutralized infection of both epithelial cells and fibroblasts and prevented cell-to-cell spread and viral dissemination from endothelial cells to leukocytes. Neutralizing monoclonal antibodies from immunized mice showed the same potency as human antibodies and targeted the same as well as additional sites on the pentamer. These results illustrate with a relevant example a general and practical approach of analytic vaccinology for the development of subunit vaccines against complex pathogens.
| S-EPMC4273412 | biostudies-literature
Project description:The four serotypes of dengue virus (DENV) cause the most important mosquito-borne viral disease in humans. The envelope (E) protein is the major target of neutralizing antibodies and contains 3 domains (domain I [DI], DII, and DIII). Recent studies reported that human monoclonal antibodies (MAbs) recognizing DIII, the D1/DII hinge, the E-dimer epitope, or a quaternary epitope involving DI/DII/DIII are more potently neutralizing than those recognizing the fusion loop (FL) of DII. Due to inefficient cleavage of the premembrane protein, DENV suspensions consist of a mixture of mature, immature, and partially immature particles. We investigated the neutralization and binding of 22 human MAbs to DENV serotype 1 (DENV1) virions with differential maturation status. Compared with FL MAbs, DIII, DI/DII hinge, and E-dimer epitope MAbs showed higher maximum binding and avidity to mature particles relative to immature particles; this feature may contribute to the strong neutralizing potency of such MAbs. FL-specific MAbs required 57 to 87% occupancy on mature particles to achieve half-maximal neutralization (NT50), whereas the potently neutralizing MAbs achieved NT50 states at 20 to 38% occupancy. Analysis of the MAb repertoire and polyclonal sera from patients with primary DENV1 infection supports the immunodominance of cross-reactive anti-E antibodies over type-specific antibodies. After depletion with viral particles from a heterologous DENV serotype, the type-specific neutralizing antibodies remained and showed binding features shared by potent neutralizing MAbs. Taken together, these findings suggest that the use of homogeneous mature DENV particles as an immunogen may induce more potent neutralizing antibodies against DENV than the use of immature or mixed particles.IMPORTANCE With an estimated 390 million infections per year, the four serotypes of dengue virus (DENV) cause the most important mosquito-borne viral disease in humans. The dengue vaccine Dengvaxia was licensed; however, its low efficacy among dengue-naive individuals and increased risk of causing severe dengue in children highlight the need for a better understanding of the role of human antibodies in immunity against DENV. DENV suspensions contain mature, immature, and partially immature particles. We investigated the binding of 22 human monoclonal antibodies (MAbs) to the DENV envelope protein on particles with different maturation states. Potently neutralizing MAbs had higher relative maximum binding and avidity to mature particles than weakly neutralizing MAbs. This was supported by analysis of MAb repertoires and polyclonal sera from patients with primary DENV infection. Together, these findings suggest that mature particles may be the optimal form of presentation of the envelope protein to induce more potent neutralizing antibodies against DENV.
| S-EPMC6232466 | biostudies-literature
Project description:The pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed serious threats to global health and economy, thus calling for the development of safe and effective vaccines. The receptor-binding domain (RBD) in the spike protein of SARS-CoV-2 is responsible for its binding to angiotensin-converting enzyme 2 (ACE2) receptor. It contains multiple dominant neutralizing epitopes and serves as an important antigen for the development of COVID-19 vaccines. Here, we showed that immunization of mice with a candidate subunit vaccine consisting of SARS-CoV-2 RBD and Fc fragment of human IgG, as an immunopotentiator, elicited high titer of RBD-specific antibodies with robust neutralizing activity against both pseudotyped and live SARS-CoV-2 infections. The mouse antisera could also effectively neutralize infection by pseudotyped SARS-CoV-2 with several natural mutations in RBD and the IgG extracted from the mouse antisera could also show neutralization against pseudotyped SARS-CoV and SARS-related coronavirus (SARSr-CoV). Vaccination of human ACE2 transgenic mice with RBD-Fc could effectively protect mice from the SARS-CoV-2 challenge. These results suggest that SARS-CoV-2 RBD-Fc has good potential to be further developed as an effective and broad-spectrum vaccine to prevent infection of the current SARS-CoV-2 and its mutants, as well as future emerging SARSr-CoVs and re-emerging SARS-CoV.
| S-EPMC7691975 | biostudies-literature
Project description:The COVID-19 pandemic urgently needs therapeutic and prophylactic interventions. Here we report the rapid identification of SARS-CoV-2 neutralizing antibodies by high-throughput single-cell RNA and VDJ sequencing of antigen-enriched B cells from 60 convalescent patients.
| EGAS00001004412 | EGA
Project description:Vaccination is considered to be the most effective countermeasure to prevent and combat the global health threats of COVID-19. People with obesity are at a greater risk of hospitalization, life-threatening illness, and adverse outcomes after having COVID-19. Therefore, a safe and effective COVID-19 vaccine for obese individuals is urgently needed. In the study, the vaccine composed of the ISA 51 adjuvant and the SARS-CoV-2 spike (S) receptor-binding domain (RBD) in conjugation with the human IgG1 Fc fragment (named as ISA 51-adjuvanted RBD-Fc vaccine) was developed and inoculated in the regular chow diet (RCD) lean mice and the high-fat diet (HFD)-induced obese mice. The S protein-specific IgG titers were largely induced in an increasing manner along with three doses of ISA 51-adjuvanted RBD-Fc vaccine without causing any harmful side effect. In the HFD mice, the S protein-specific IgG titers can be quickly observed 2 weeks post the first inoculation. The antisera elicited by the ISA 51-adjuvanted RBD-Fc vaccine in the RCD and HFD mice exhibited potent SARS-CoV-2 neutralizing activities in the plaque reduction neutralization test (PRNT) assays and showed similar specificity for recognizing the key residues in the RBD which were involved in interacting with angiotensin-converting enzyme 2 (ACE2) receptor. The immune efficacy of the ISA 51-adjuvanted RBD-Fc vaccine in the HFD mice can be sustainably maintained with the PRNT50 values of 1.80-1.91×10-3 for at least 8 weeks post the third inoculation. Collectively, the RBD-Fc-based immunogen and the ISA 51-adjuvanted formulation can be developed as an effective COVID-19 vaccine for obese individuals. KEY POINTS: • The ISA 51-adjuvanted RBD-Fc vaccine can induce potent SARS-CoV-2 neutralizing antibodies in the obese mouse • The antibodies elicited by the ISA 51-adjuvanted RBD-Fc vaccine can bind to the key RBD residues involved in interacting with ACE2 • The immune efficacy of the ISA 51-adjuvanted RBD-Fc vaccine can be sustainably maintained for at least 8 weeks post the third inoculation.
| S-EPMC10049902 | biostudies-literature
Project description:Middle East respiratory syndrome coronavirus (MERS-CoV), a highly pathogenic coronavirus in the same Betacoronavirus genus and Coronaviridae family as SARS-CoV-2, continues to post a threat to human health. Mortality remains high; therefore, there is a need to develop effective vaccines to prevent MERS-CoV infection. The receptor-binding domain (RBD) within the MERS-CoV spike (S) protein is a critical vaccine target. The latest mRNA technology has enabled rapid development of much-needed vaccines with high efficiency and scalable manufacturing capacity. Here, we designed a mRNA vaccine encoding the RBD of MERS-CoV S protein (RBD-mRNA) and evaluated its immunogenicity and protective efficacy in a mouse model. The data showed that nucleoside-modified RBD-mRNA, but not RBD-mRNA lacking the nucleoside modification, was stable and elicited broadly and durable neutralizing antibody and cellular immune responses, which neutralized the original strain and multiple MERS-CoV variants. Among all immunization routes tested, the intradermal route was appropriate for this RBD-mRNA to induce strong B-cell responses and the highest neutralizing antibody titers. Importantly, injection of nucleoside-modified RBD-mRNA through the intradermal route protected immunized mice against challenge with MERS-CoV. This protection correlated with serum neutralizing antibody titers. Overall, we have developed an effective MERS-CoV RBD-based mRNA vaccine (with potential for further development) that prevents infection by divergent strains of MERS-CoV.
| S-EPMC10278997 | biostudies-literature
Project description:SARS-CoV-2, the virus responsible for the COVID-19 pandemic, belongs to the betacoronavirus genus. This virus has a high mutation rate, which rapidly evolves into new variants with different properties, such as increased transmissibility or immune evasion. Currently, the most prevalent global SARS-CoV-2 variant is Omicron, which is more transmissible than previous variants. Current available vaccines may be less effective against some currently existing SARS-CoV-2 variants, including the Omicron variant. The S1 subunit of the spike protein of SARS-CoV-2 has been a major target for COVID-19 vaccine development. It plays a crucial role in the virus's entry into host cells and is the primary target for neutralizing antibodies. In this study, the S1 subunit of the spike protein of SARS-CoV-2 was engineered and produced at a high level in Nicotiana benthamiana plant. The expression level of the recombinant S1 protein was greater than the 0.5-g/kg fresh weight, and the purification yield was at least ~0.3 g of pure protein/kg of plant biomass, which would make a plant-produced S1 antigen an ideal vaccine candidate for commercialization. Purified, the plant-produced SARS-CoV-2 S1 protein exhibited significantly higher binding to the SARS-CoV-2 receptor, angiotensin-converting enzyme 2 (ACE2). Moreover, we also show that recombinant S1 protein/antigen-elicited antibodies can neutralize the Delta or Omicron variants. Collectively, our results demonstrate that a plant-produced S1 antigen could be a promising vaccine candidate against SARS-CoV-2 variants including Omicron.
| S-EPMC10682712 | biostudies-literature
Project description:In the context of continuous emergence of SARS-CoV-2 variants of concern (VOCs), one strategy to prevent the severe outcomes of COVID-19 is developing safe and effective broad-spectrum vaccines. Here, we present preclinical studies of a RBD vaccine derived from the Gamma SARS-CoV-2 variant adjuvanted with Alum. The Gamma-adapted RBD vaccine is more immunogenic than the Ancestral RBD vaccine in terms of inducing broader neutralizing antibodies. The Gamma RBD presents more immunogenic B-cell restricted epitopes and induces a higher proportion of specific-B cells and plasmablasts than the Ancestral RBD version. The Gamma-adapted vaccine induces antigen specific T cell immune responses and confers protection against Ancestral and Omicron BA.5 SARS-CoV-2 challenge in mice. Moreover, the Gamma RBD vaccine induces higher and broader neutralizing antibody activity than homologous booster vaccination in mice previously primed with different SARS-CoV-2 vaccine platforms. Our study indicates that the adjuvanted Gamma RBD vaccine is highly immunogenic and a broad-spectrum vaccine candidate.
| S-EPMC10837449 | biostudies-literature
Project description: Not available
| S-EPMC7586990 | biostudies-literature
Project description:There is still no safe and effective vaccine against dengue virus infection. Epidemics of dengue virus infection are increasingly a threat to human health around the world. Antibodies generated in response to dengue infection have been shown to impact disease development and effectiveness of dengue vaccine. In this study, we investigated monoclonal antibody responses to an experimental dengue vaccine in rhesus macaques. Variable regions of both heavy chain (VH) and light chain (VL) were cloned from single antibody-secreting B cells. A total of 780 monoclonal antibodies (mAbs) composed of paired VH and VL were characterized. Results show that the vaccination induces mAbs with diverse germline sequences and a wide range of binding affinities. Six potent neutralizing mAbs were identified among 130 dengue envelope protein binders. Critical amino acids for each neutralizing antibody binding to the dengue envelope protein were identified by alanine scanning of mutant libraries. Diverse epitopes were identified, including epitopes on the lateral ridge of DIII, the I-III hinge, the bc loop adjacent to the fusion loop of DII, and the β-strands and loops of DI. Significantly, one of the neutralizing mAbs has a previously unknown epitope in DII at the interface of the envelope and membrane protein and is capable of neutralizing all four dengue serotypes. Taken together, the results of this study not only provide preclinical validation for the tested experimental vaccine, but also shed light on a potential application of the rhesus macaque model for better dengue vaccine evaluation and design of vaccines and immunization strategies.
| S-EPMC6553876 | biostudies-literature