scholarly journals A recombinant receptor-binding domain in trimeric form generates completely protective immunity against SARS-CoV-2 infection in nonhuman primates

2021 ◽  
Author(s):  
Limin Yang ◽  
Deyu Tian ◽  
Jian-bao Han ◽  
Wenhui Fan ◽  
Yuan Zhang ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Nonhuman Primates ◽  
Rhesus Macaques ◽  
Vaccination Strategy ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Recombinant Receptor ◽  
High Level ◽  
Cellular Immune

Safe and effective vaccination is critical to combatting the COVID-19 pandemic. Here, we developed a trimeric SARS-CoV-2 receptor-binding domain (RBD) subunit vaccine candidate that simulates the natural structure of the spike (S) trimer glycoprotein. Immunization with RBD-trimer induced robust humoral and cellular immune responses and a high level of neutralizing antibodies that were maintained for at least 4 months. Moreover, the antibodies that were produced in response to the vaccine effectively neutralized the SARS-CoV-2 501Y.V2 variant. Of note, when the titers of the antibodies dropped to a sufficiently low level, only one boost quickly activated the anamnestic immune response, resulting in complete protection against the SARS-CoV-2 challenge in rhesus macaques without typical histopathological changes or viral replication in the lungs and other respiratory tissues. Our results indicated that immunization with SARS-CoV-2 RBD-trimer could raise long-term and broad immunity protection in nonhuman primates, thereby offering an optimal vaccination strategy against COVID-19.

scholarly journals Yeast-Expressed SARS-CoV Recombinant Receptor-Binding Domain (RBD219-N1) Formulated with Aluminum Hydroxide Induces Protective Immunity and Reduces Immune Enhancement

2020 ◽  
Author(s):  
Wen-Hsiang Chen ◽  
Xinrong Tao ◽  
Anurodh Agrawal ◽  
Abdullah Algaissi ◽  
Bi-Hung Peng ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Pseudotyped Virus ◽  
Receptor Binding Domain ◽  
Protein Vaccine ◽  
S Protein ◽  
Recombinant Receptor ◽  
High Level

AbstractWe developed a severe acute respiratory syndrome (SARS) subunit recombinant protein vaccine candidate based on a high-yielding, yeast-engineered, receptor-binding domain (RBD219-N1) of the SARS beta-coronavirus (SARS-CoV) spike (S) protein. When formulated with Alhydrogel®, RBD219-N1 induced high-level neutralizing antibodies against both pseudotyped virus and a clinical (mouse-adapted) isolate of SARS-CoV. Here, we report that mice immunized with RBD219-N1/Alhydrogel® were fully protected from lethal SARS-CoV challenge (0% mortality), compared to ∼ 30% mortality in mice when immunized with the SARS S protein formulated with Alhydrogel®, and 100% mortality in negative controls. An RBD219-N1 formulation Alhydrogel® was also superior to the S protein, unadjuvanted RBD, and AddaVax (MF59-like adjuvant)-formulated RBD in inducing specific antibodies and preventing cellular infiltrates in the lungs upon SARS-CoV challenge. Specifically, a formulation with a 1:25 ratio of RBD219-N1 to Alhydrogel® provided high neutralizing antibody titers, 100% protection with non-detectable viral loads with minimal or no eosinophilic pulmonary infiltrates. As a result, this vaccine formulation is under consideration for further development against SARS-CoV and potentially other emerging and re-emerging beta-CoVs such as SARS-CoV-2.

scholarly journals Comparative Immunogenicity of the Recombinant Receptor-Binding Domain of Protein S SARS-CoV-2 Obtained in Prokaryotic and Mammalian Expression Systems

Vaccines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 96
Author(s):  
Iuliia A. Merkuleva ◽  
Dmitry N. Shcherbakov ◽  
Mariya B. Borgoyakova ◽  
Daniil V. Shanshin ◽  
Andrey P. Rudometov ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Expression System ◽  
Protein S ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Expression Systems ◽  
Mice Model ◽  
Mammalian Expression ◽  
Recombinant Receptor

The receptor-binding domain (RBD) of the protein S SARS-CoV-2 is considered to be one of the appealing targets for developing a vaccine against COVID-19. The choice of an expression system is essential when developing subunit vaccines, as it ensures the effective synthesis of the correctly folded target protein, and maintains its antigenic and immunogenic properties. Here, we describe the production of a recombinant RBD protein using prokaryotic (pRBD) and mammalian (mRBD) expression systems, and compare the immunogenicity of prokaryotic and mammalian-expressed RBD using a BALB/c mice model. An analysis of the sera from mice immunized with both variants of the protein revealed that the mRBD expressed in CHO cells provides a significantly stronger humoral immune response compared with the RBD expressed in E.coli cells. A specific antibody titer of sera from mice immunized with mRBD was ten-fold higher than the sera from the mice that received pRBD in ELISA, and about 100-fold higher in a neutralization test. The data obtained suggests that mRBD is capable of inducing neutralizing antibodies against SARS-CoV-2.

scholarly journals Receptor-Binding Domain Proteins of SARS-CoV-2 Variants Elicited Robust Antibody Responses Cross-Reacting with Wild-Type and Mutant Viruses in Mice

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1383
Author(s):  
Juan Shi ◽  
Xiaoxiao Jin ◽  
Yan Ding ◽  
Xiaotao Liu ◽  
Anran Shen ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Polyclonal Antibodies ◽  
Neutralizing Antibody ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Wild Type ◽  
Neutralization Capacity ◽  
Antibody Titers ◽  
High Level

Multiple variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have spread around the world, but the neutralizing effects of antibodies induced by the existing vaccines have declined, which highlights the importance of developing vaccines against mutant virus strains. In this study, nine receptor-binding domain (RBD) proteins of the SARS-CoV-2 variants (B.1.1.7, B.1.351 and P.1 lineages) were constructed and fused with the Fc fragment of human IgG (RBD-Fc). These RBD-Fc proteins contained single or multiple amino acid substitutions at prevalent mutation points of spike protein, which enabled them to bind strongly to the polyclonal antibodies specific for wild-type RBD and to the recombinant human ACE2 protein. In the BALB/c, mice were immunized with the wild-type RBD-Fc protein first and boosted twice with the indicated mutant RBD-Fc proteins later. All mutant RBD-Fc proteins elicited high-level IgG antibodies and cross-neutralizing antibodies. The RBD-Fc proteins with multiple substitutions tended to induce higher antibody titers and neutralizing-antibody titers than the single-mutant RBD-Fc proteins. Meanwhile, both wild-type RBD-Fc protein and mutant RBD-Fc proteins induced significantly decreased neutralization capacity to the pseudovirus of B.1.351 and P.1 lineages than to the wild-type one. These data will facilitate the design and development of RBD-based subunit vaccines against SARS-COV-2 and its variants.

scholarly journals Stereotypic neutralizing VH antibodies against SARS-CoV-2 spike protein receptor binding domain in COVID-19 patients and healthy individuals

2021 ◽  
pp. eabd6990
Author(s):  
Sang Il Kim ◽  
Jinsung Noh ◽  
Sujeong Kim ◽  
Younggeun Choi ◽  
Duck Kyun Yoo ◽  
...  
Keyword(s):  
B Cells ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
De Novo ◽  
Binding Domain ◽  
Host Cells ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Healthy Individuals

Stereotypic antibody clonotypes exist in healthy individuals and may provide protective immunity against viral infections by neutralization. We observed that 13 out of 17 patients with COVID-19 had stereotypic variable heavy chain (VH) antibody clonotypes directed against the receptor-binding domain (RBD) of SARS-CoV-2 spike protein. These antibody clonotypes were comprised of immunoglobulin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobulin heavy joining (IGHJ)6 genes. These clonotypes included IgM, IgG3, IgG1, IgA1, IgG2, and IgA2 subtypes and had minimal somatic mutations, which suggested swift class switching after SARS-CoV-2 infection. The different immunoglobulin heavy variable chains were paired with diverse light chains resulting in binding to the RBD of SARS-CoV-2 spike protein. Human antibodies specific for the RBD can neutralize SARS-CoV-2 by inhibiting entry into host cells. We observed that one of these stereotypic neutralizing antibodies could inhibit viral replication in vitro using a clinical isolate of SARS-CoV-2. We also found that these VH clonotypes existed in six out of 10 healthy individuals, with IgM isotypes predominating. These findings suggest that stereotypic clonotypes can develop de novo from naïve B cells and not from memory B cells established from prior exposure to similar viruses. The expeditious and stereotypic expansion of these clonotypes may have occurred in patients infected with SARS-CoV-2 because they were already present.

scholarly journals mRNA vaccination boosts cross-variant neutralizing antibodies elicited by SARS-CoV-2 infection

Science ◽  
2021 ◽  
pp. eabg9175 ◽  
Author(s):  
Leonidas Stamatatos ◽  
Julie Czartoski ◽  
Yu-Hsin Wan ◽  
Leah J. Homad ◽  
Vanessa Rubin ◽  
...  
Keyword(s):  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Previous Infection

Emerging SARS-CoV-2 variants have raised concerns about resistance to neutralizing antibodies elicited by previous infection or vaccination. We examined whether sera from recovered and naïve donors collected prior to, and following immunizations with existing mRNA vaccines, could neutralize the Wuhan-Hu-1 and B.1.351 variants. Pre-vaccination sera from recovered donors neutralized Wuhan-Hu-1 and sporadically neutralized B.1.351, but a single immunization boosted neutralizing titers against all variants and SARS-CoV-1 by up to 1000-fold. Neutralization was due to antibodies targeting the receptor binding domain and was not boosted by a second immunization. Immunization of naïve donors also elicited cross-neutralizing responses, but at lower titers. Our study highlights the importance of vaccinating both uninfected and previously infected persons to elicit cross-variant neutralizing antibodies.

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