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1.
Signal Transduct Target Ther ; 6(1): 438, 2021 12 24.
Article in English | MEDLINE | ID: covidwho-1585880

ABSTRACT

Messenger RNA (mRNA) vaccine technology has shown its power in preventing the ongoing COVID-19 pandemic. Two mRNA vaccines targeting the full-length S protein of SARS-CoV-2 have been authorized for emergency use. Recently, we have developed a lipid nanoparticle-encapsulated mRNA (mRNA-LNP) encoding the receptor-binding domain (RBD) of SARS-CoV-2 (termed ARCoV), which confers complete protection in mouse model. Herein, we further characterized the protection efficacy of ARCoV in nonhuman primates and the long-term stability under normal refrigerator temperature. Intramuscular immunization of two doses of ARCoV elicited robust neutralizing antibodies as well as cellular response against SARS-CoV-2 in cynomolgus macaques. More importantly, ARCoV vaccination in macaques significantly protected animals from acute lung lesions caused by SARS-CoV-2, and viral replication in lungs and secretion in nasal swabs were completely cleared in all animals immunized with low or high doses of ARCoV. No evidence of antibody-dependent enhancement of infection was observed throughout the study. Finally, extensive stability assays showed that ARCoV can be stored at 2-8 °C for at least 6 months without decrease of immunogenicity. All these promising results strongly support the ongoing clinical trial.


Subject(s)
COVID-19 Vaccines/pharmacology , COVID-19/immunology , Immunogenicity, Vaccine , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , /pharmacology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Humans , Macaca fascicularis , Vero Cells , /immunology
2.
Front Immunol ; 12: 789905, 2021.
Article in English | MEDLINE | ID: covidwho-1581321

ABSTRACT

Facing the imminent need for vaccine candidates with cross-protection against globally circulating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutants, we present a conserved antigenic peptide RBD9.1 with both T-cell and B-cell epitopes. RBD9.1 can be recognized by coronavirus disease 2019 (COVID-19) convalescent serum, particularly for those with high neutralizing potency. Immunization with RBD9.1 can successfully induce the production of the receptor-binding domain (RBD)-specific antibodies in Balb/c mice. Importantly, the immunized sera exhibit sustained neutralizing efficacy against multiple dominant SARS-CoV-2 variant strains, including B.1.617.2 that carries a point mutation (SL452R) within the sequence of RBD9.1. Specifically, SY451 and SY454 are identified as the key amino acids for the binding of the induced RBD-specific antibodies to RBD9.1. Furthermore, we have confirmed that the RBD9.1 antigenic peptide can induce a S448-456 (NYNYLYRLF)-specific CD8+ T-cell response. Both RBD9.1-specific B cells and the S448-456-specific T cells can still be activated more than 3 months post the last immunization. This study provides a potential vaccine candidate that can generate long-term protective efficacy over SARS-CoV-2 variants, with the unique functional mechanism of activating both humoral and cellular immunity.


Subject(s)
Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunity, Cellular/immunology , Immunity, Humoral/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19 Vaccines/pharmacology , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Humans , Mice , Mice, Inbred BALB C , SARS-CoV-2/immunology , Vaccines, Subunit/immunology
3.
Curr Med Sci ; 41(6): 1052-1064, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1588743

ABSTRACT

The ongoing Coronavirus disease 19 pandemic has likely changed the world in ways not seen in the past. Neutralizing antibody (NAb) assays play an important role in the management of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) outbreak. Using these tools, we can assess the presence and duration of antibody-mediated protection in naturally infected individuals, screen convalescent plasma preparations for donation, test the efficacy of immunotherapy, and analyze NAb titers and persistence after vaccination to predict vaccine-induced protective effects. This review briefly summarizes the various methods used for the detection of SARS-CoV-2 NAbs and compares their advantages and disadvantages to facilitate their development and clinical application.


Subject(s)
Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 Serological Testing/methods , COVID-19/immunology , Neutralization Tests/methods , SARS-CoV-2/immunology , COVID-19/prevention & control , COVID-19/therapy , COVID-19 Serological Testing/trends , COVID-19 Vaccines/pharmacology , Humans , Immunization, Passive , Neutralization Tests/trends , Pandemics/prevention & control
4.
Clin Appl Thromb Hemost ; 27: 10760296211066942, 2021.
Article in English | MEDLINE | ID: covidwho-1574701

ABSTRACT

INTRODUCTION: We conducted a cross-sectional survey as a part of an educational program in collaboration with the Global Thrombosis Forum (GTF), an affiliate of North American Thrombosis Forum (NATF), and Loyola University about public perceptions of COVID-19 and COVID-19 vaccinations in the US. In this study, we are reporting the results of this survey. MATERIALS AND METHODS: The survey, in the form of a questionnaire, has been developed by GTF and faculty members. A prepared questionnaire was sent to the members of the Georgia and Illinois communities. RESULTS: In our current study, the COVID-19 vaccine willingness rate was 94.5% and vaccination rate was 90.9%. In multivariate analysis believing to have enough information about the safety and efficacy of COVID-19 vaccines (OR: 3.730, 95% CI: 1.199-11.603, p: 0.023) and gender (OR: 0.123, 95% CI: 0.016-0.967, p: 0.046) were significant predictors for vaccine willingness. Previous COVID-19 infection (OR: 0.215, 95% CI: 0.061-0.758, p: 0.017), moderate and severe effects of COVID-19 pandemic on participant's life (OR: 4.631, 95% CI 1.681-12.760, p: 0.003) and believing to have enough information about the safety and efficacy of COVID-19 vaccines (OR: 4.119, 95% CI: 1.508-11.253, p: 0.006) were significant predictors for final vaccination status. CONCLUSION: In conclusion, currently vaccination remains one of the most effective tools in the fight against the COVID-19 pandemic. The vaccine hesitancy is a complex phenomenon that is driven by individuals' perceptions of safety, and efficiency of the vaccines. We must continue to educate the public and communities that vaccines are safe, that they are effective and that they are still required even after a COVID-19 infection.


Subject(s)
COVID-19 Vaccines/therapeutic use , SARS-CoV-2/metabolism , Vaccination/methods , Adolescent , Adult , COVID-19 Vaccines/pharmacology , Cross-Sectional Studies , Female , Humans , Male , Perception , Pilot Projects , Surveys and Questionnaires , Young Adult
5.
Int J Mol Sci ; 22(24)2021 Dec 14.
Article in English | MEDLINE | ID: covidwho-1572495

ABSTRACT

The pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has upended healthcare systems and economies around the world. Rapid understanding of the structural biology and pathogenesis of SARS-CoV-2 has allowed the development of emergency use or FDA-approved vaccines and various candidate vaccines. Among the recently developed SARS-CoV-2 candidate vaccines, natural protein-based nanoparticles well suited for multivalent antigen presentation and enhanced immune stimulation to elicit potent humoral and cellular immune responses are currently being investigated. This mini-review presents recent innovations in protein-based nanoparticle vaccines against SARS-CoV-2. The design and strategy of displaying antigenic domains, including spike protein, receptor-binding domain (RBD), and other domains on the surface of various protein-based nanoparticles and the performance of the developed nanoparticle-based vaccines are highlighted. In the final part of this review, we summarize and discuss recent advances in clinical trials and provide an outlook on protein-based nanoparticle vaccines.


Subject(s)
COVID-19 Vaccines/immunology , Nanoparticles/chemistry , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigen Presentation/immunology , COVID-19/immunology , COVID-19 Vaccines/pharmacology , Humans , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Vaccines/immunology
6.
Int J Mol Sci ; 22(24)2021 Dec 08.
Article in English | MEDLINE | ID: covidwho-1554850

ABSTRACT

The COVID-19 pandemic continues to spread around the world and remains a major public health threat. Vaccine inefficiency, vaccination breakthroughs and lack of supply, especially in developing countries, as well as the fact that a non-negligible part of the population either refuse vaccination or cannot be vaccinated due to age, pre-existing illness or non-response to existing vaccines intensify this issue. This might also contribute to the emergence of new variants, being more efficiently transmitted, more virulent and more capable of escaping naturally acquired and vaccine-induced immunity. Hence, the need of effective and viable prevention options to reduce viral transmission is of outmost importance. In this study, we investigated the antiviral effect of iota-, lambda- and kappa-carrageenan, sulfated polysaccharides extracted from red seaweed, on SARS-CoV-2 Wuhan type and the spreading variants of concern (VOCs) Alpha, Beta, Gamma and Delta. Carrageenans as part of broadly used nasal and mouth sprays as well as lozenges have the potential of first line defense to inhibit the infection and transmission of SARS-CoV-2. Here, we demonstrate by using a SARS-CoV-2 spike pseudotyped lentivirus particles (SSPL) system and patient-isolated SARS-CoV-2 VOCs to infect transgenic A549ACE2/TMPRSS2 and Calu-3 human lung cells that all three carrageenan types exert antiviral activity. Iota-carrageenan exhibits antiviral activity with comparable IC50 values against the SARS-CoV-2 Wuhan type and the VOCs. Altogether, these results indicate that iota-carrageenan might be effective for prophylaxis and treatment of SARS-CoV-2 infections independent of the present and potentially future variants.


Subject(s)
COVID-19/drug therapy , COVID-19/virology , Carrageenan/pharmacology , SARS-CoV-2/drug effects , Virus Replication/drug effects , Animals , Antiviral Agents/pharmacology , COVID-19/epidemiology , COVID-19/immunology , COVID-19 Vaccines/pharmacology , Chlorocebus aethiops , HEK293 Cells , Humans , Pandemics , Polysaccharides/pharmacology , SARS-CoV-2/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Vaccination/methods , Vero Cells
8.
J Immunol ; 207(11): 2681-2687, 2021 12 01.
Article in English | MEDLINE | ID: covidwho-1506155

ABSTRACT

Due to limited access to vaccines, many countries have only administered a single dose of the AZD1222, whereas the dosage intervals have increased ≥4 wk. We sought to investigate the immunogenicity of a single dose of vaccine at ≥16 wk postimmunization. Severe acute respiratory syndrome coronavirus 2-specific Abs in 553 individuals and Abs to the receptor-binding domain of the Wuhan virus (wild-type) and the variants of concern, angiotensin-converting enzyme 2 receptor blocking Abs ex vivo and cultured IFN-γ T cell (Homo sapiens) responses and B cell (H. sapiens) ELISPOT responses, were investigated in a subcohort. The seropositivity rates in those >70 y of age (93.7%) was not significantly different compared with other age groups (97.7-98.2; Pearson χ2 = 7.8; p = 0.05). The Ab titers (Ab index) significantly declined (p < 0.0001) with increase in age. A total of 18 of 69 (26.1%) of individuals did not have angiotensin-converting enzyme 2 receptor-blocking Abs, whereas responses to the receptor-binding domain of wild-type (p = 0.03), B.1.1.7 (p = 0.04), and B.1.617.2 (p = 0.02) were significantly lower in those who were >60 y. Ex vivo IFN-γ T cell ELISPOT responses were seen in 10 of 66 (15.1%), whereas only a few expressed CD107a. However, >85% had a high frequency of cultured IFN-γ T cell ELISPOT responses and B cell ELISPOTs. Virus-specific Abs were maintained at ≥16 wk after receiving a single dose of AZD1222, although levels were lower to variants of concern, especially in older individuals. A single dose induced a high frequency of memory T and B cell responses.


Subject(s)
COVID-19 Vaccines/pharmacology , COVID-19/drug therapy , SARS-CoV-2/drug effects , Administration, Oral , Adult , Aged , Aged, 80 and over , B-Lymphocytes/drug effects , B-Lymphocytes/immunology , COVID-19/immunology , COVID-19 Vaccines/administration & dosage , Female , Humans , Male , Middle Aged , SARS-CoV-2/immunology , Young Adult
9.
PLoS Med ; 18(11): e1003823, 2021 11.
Article in English | MEDLINE | ID: covidwho-1504361

ABSTRACT

BACKGROUND: Healthcare workers (HCWs) and ethnic minority groups are at increased risk of COVID-19 infection and adverse outcomes. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination is now available for frontline UK HCWs; however, demographic/occupational associations with vaccine uptake in this cohort are unknown. We sought to establish these associations in a large UK hospital workforce. METHODS AND FINDINGS: We conducted cross-sectional surveillance examining vaccine uptake amongst all staff at University Hospitals of Leicester NHS Trust. We examined proportions of vaccinated staff stratified by demographic factors, occupation, and previous COVID-19 test results (serology/PCR) and used logistic regression to identify predictors of vaccination status after adjustment for confounders. We included 19,044 HCWs; 12,278 (64.5%) had received SARS-CoV-2 vaccination. Compared to White HCWs (70.9% vaccinated), a significantly smaller proportion of ethnic minority HCWs were vaccinated (South Asian, 58.5%; Black, 36.8%; p < 0.001 for both). After adjustment for age, sex, ethnicity, deprivation, occupation, SARS-CoV-2 serology/PCR results, and COVID-19-related work absences, factors found to be negatively associated with vaccine uptake were younger age, female sex, increased deprivation, pregnancy, and belonging to any non-White ethnic group (Black: adjusted odds ratio [aOR] 0.30, 95% CI 0.26-0.34, p < 0.001; South Asian: aOR 0.67, 95% CI 0.62-0.72, p < 0.001). Those who had previously had confirmed COVID-19 (by PCR) were less likely to be vaccinated than those who had tested negative. Limitations include data being from a single centre, lack of data on staff vaccinated outside the hospital system, and that staff may have taken up vaccination following data extraction. CONCLUSIONS: Ethnic minority HCWs and those from more deprived areas as well as younger staff and female staff are less likely to take up SARS-CoV-2 vaccination. These findings have major implications for the delivery of SARS-CoV-2 vaccination programmes, in HCWs and the wider population, and should inform the national vaccination programme to prevent the disparities of the pandemic from widening.


Subject(s)
COVID-19 Vaccines/pharmacology , COVID-19/prevention & control , Health Personnel/statistics & numerical data , SARS-CoV-2/pathogenicity , Vaccination/statistics & numerical data , COVID-19/epidemiology , Delivery of Health Care/statistics & numerical data , Humans , Minority Groups , United Kingdom/epidemiology
10.
J Clin Invest ; 131(20)2021 10 15.
Article in English | MEDLINE | ID: covidwho-1501861

ABSTRACT

The mRNA-1273 vaccine is effective against SARS-CoV-2 and was granted emergency use authorization by the FDA. Clinical studies, however, cannot provide the controlled response to infection and complex immunological insight that are only possible with preclinical studies. Hamsters are the only model that reliably exhibits severe SARS-CoV-2 disease similar to that in hospitalized patients, making them pertinent for vaccine evaluation. We demonstrate that prime or prime-boost administration of mRNA-1273 in hamsters elicited robust neutralizing antibodies, ameliorated weight loss, suppressed SARS-CoV-2 replication in the airways, and better protected against disease at the highest prime-boost dose. Unlike in mice and nonhuman primates, low-level virus replication in mRNA-1273-vaccinated hamsters coincided with an anamnestic response. Single-cell RNA sequencing of lung tissue permitted high-resolution analysis that is not possible in vaccinated humans. mRNA-1273 prevented inflammatory cell infiltration and the reduction of lymphocyte proportions, but enabled antiviral responses conducive to lung homeostasis. Surprisingly, infection triggered transcriptome programs in some types of immune cells from vaccinated hamsters that were shared, albeit attenuated, with mock-vaccinated hamsters. Our results support the use of mRNA-1273 in a 2-dose schedule and provide insight into the potential responses within the lungs of vaccinated humans who are exposed to SARS-CoV-2.


Subject(s)
COVID-19 Vaccines/pharmacology , COVID-19/immunology , COVID-19/prevention & control , Lung/immunology , SARS-CoV-2 , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Disease Models, Animal , Female , Humans , Immunization, Secondary , Lung/pathology , Lung/virology , Lymphocyte Activation , Mesocricetus , SARS-CoV-2/immunology , SARS-CoV-2/physiology , Single-Cell Analysis , Virus Replication
11.
PLoS One ; 16(10): e0258540, 2021.
Article in English | MEDLINE | ID: covidwho-1496510

ABSTRACT

As of May 2021, over 286 million coronavirus 2019 (COVID-19) vaccine doses have been administered across the country. This data is promising, however there are still populations that, despite availability, are declining vaccination. We reviewed vaccine likelihood and receptiveness to recommendation from a doctor or nurse survey responses from 101,048 adults (≥18 years old) presenting to 442 primary care clinics in 8 states and the District of Columbia. Occupation was self-reported and demographic information extracted from the medical record, with 58.3% (n = 58,873) responding they were likely to receive the vaccine, 23.6% (n = 23,845) unlikely, and 18.1% (n = 18,330) uncertain. We found that essential workers were 18% less likely to receive the COVID-19 vaccination. Of those who indicated they were not already "very likely" to receive the vaccine, a recommendation from a nurse or doctor resulted in 16% of respondents becoming more likely to receive the vaccine, although certain occupations were less likely than others to be receptive to recommendations. To our knowledge, this is the first study to look at vaccine intent and receptiveness to recommendations from a doctor or nurse across specific essential worker occupations, and may help inform future early phase, vaccine rollouts and public health measure implementations.


Subject(s)
COVID-19/psychology , Vaccination Refusal/psychology , Vaccination/trends , Adult , Aged , Aged, 80 and over , COVID-19/prevention & control , COVID-19 Vaccines/pharmacology , Demography/methods , Female , Humans , Intention , Male , Middle Aged , SARS-CoV-2/pathogenicity , Social Class , United States , Vaccination/psychology
12.
Pharmacotherapy ; 41(10): 837-850, 2021 10.
Article in English | MEDLINE | ID: covidwho-1479434

ABSTRACT

As of August 2021, there were three COVID-19 vaccines available in the United States for the prevention of coronavirus 2019 (COVID-19). The purpose of this narrative review is to examine the early experience from the Emergency Use Authorization (EUA) of BNT162b2 (Pfizer, Inc./BioNTech), mRNA-1273 (Moderna, Inc.), and Ad26.COV2.S (Johnson and Johnson/Janssen Global Services, LLC) through July 2021. The EUA data from the clinical trials have largely been corroborated by real-world effectiveness investigations post-authorization. These studies indicate that immunity is obtained within 2 weeks post-vaccination and may endure for 6 months. The immunity conferred by the vaccines may also be effective against SARS-CoV-2 variants of concern. Additionally, populations not included in the emergency use authorization studies may also benefit from vaccination. This look back at the initial clinical experience can be used by the global community to inform and develop COVID-19 vaccine programs.


Subject(s)
COVID-19 Vaccines , COVID-19 , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines/classification , COVID-19 Vaccines/immunology , COVID-19 Vaccines/pharmacology , Clinical Trials as Topic , Comparative Effectiveness Research , Humans , Immunogenicity, Vaccine , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , Societies, Pharmaceutical/trends
13.
Acc Chem Res ; 54(21): 4001-4011, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1475239

ABSTRACT

Since the U.S. Food and Drug Administration (FDA) granted emergency use authorization for two mRNA vaccines against SARS-CoV-2, mRNA-based technology has attracted broad attention from the scientific community to investors. When delivered intracellularly, mRNA has the ability to produce various therapeutic proteins, enabling the treatment of a variety of illnesses, including but not limited to infectious diseases, cancers, and genetic diseases. Accordingly, mRNA holds significant therapeutic potential and provides a promising means to target historically hard-to-treat diseases. Current clinical efforts harnessing mRNA-based technology are focused on vaccination, cancer immunotherapy, protein replacement therapy, and genome editing. The clinical translation of mRNA-based technology has been made possible by leveraging nanoparticle delivery methods. However, the application of mRNA for therapeutic purposes is still challenged by the need for specific, efficient, and safe delivery systems.This Account highlights key advances in designing and developing combinatorial synthetic lipid nanoparticles (LNPs) with distinct chemical structures and properties for in vitro and in vivo intracellular mRNA delivery. LNPs represent the most advanced nonviral nanoparticle delivery systems that have been extensively investigated for nucleic acid delivery. The aforementioned COVID-19 mRNA vaccines and one LNP-based small interfering RNA (siRNA) drug (ONPATTRO) have received clinical approval from the FDA, highlighting the success of synthetic ionizable lipids for in vivo nucleic acid delivery. In this Account, we first summarize the research efforts from our group on the development of bioreducible and biodegradable LNPs by leveraging the combinatorial chemistry strategy, such as the Michael addition reaction, which allows us to easily generate a large set of lipidoids with diverse chemical structures. Next, we discuss the utilization of a library screening strategy to identify optimal LNPs for targeted mRNA delivery and showcase the applications of the optimized LNPs in cell engineering and genome editing. Finally, we outline key challenges to the clinical translation of mRNA-based therapies and propose an outlook for future directions of the chemical design and optimization of LNPs to improve the safety and specificity of mRNA drugs. We hope this Account provides insight into the rational design of LNPs for facilitating the development of mRNA therapeutics, a transformative technology that promises to revolutionize future medicine.


Subject(s)
COVID-19 Vaccines/pharmacology , Gene Editing , Gene Transfer Techniques , Lipids/chemistry , Nanoparticles/chemistry , RNA, Messenger/pharmacology , COVID-19/drug therapy , COVID-19 Vaccines/chemistry , Genetic Therapy , Humans , RNA, Messenger/chemistry , SARS-CoV-2/drug effects
14.
Biochemistry (Mosc) ; 86(10): 1275-1287, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1476404

ABSTRACT

A new platform for creating anti-coronavirus epitope vaccines has been developed. Two loop-like epitopes with lengths of 22 and 42 amino acid residues were selected from the receptor-binding motif of the Spike protein from the SARS-CoV-2 virus that participate in a large number of protein-protein interactions in the complexes with ACE2 and neutralizing antibodies. Two types of hybrid proteins, including one of the two selected epitopes, were constructed. To fix conformation of the selected epitopes, an approach using protein scaffolds was used. The homologue of Rop protein from the Escherichia coli ColE1 plasmid containing helix-turn-helix motif was used as an epitope scaffold for the convergence of C- and N-termini of the loop-like epitopes. Loop epitopes were inserted into the turn region. The conformation was additionally fixed by a disulfide bond formed between the cysteine residues present within the epitopes. For the purpose of multimerization, either aldolase from Thermotoga maritima, which forms a trimer in solution, or alpha-helical trimerizer of the Spike protein from SARS-CoV-2, was attached to the epitopes incorporated into the Rop-like protein. To enable purification on the heparin-containing sorbents, a short fragment from the heparin-binding hemagglutinin of Mycobacterium tuberculosis was inserted at the C-terminus of the hybrid proteins. All the obtained proteins demonstrated high level of immunogenicity after triplicate parenteral administration to mice. Sera from the mice immunized with both aldolase-based hybrid proteins and the Spike protein SARS-CoV-2 trimerizer-based protein with a longer epitope interacted with both the inactivated SARS-CoV-2 virus and the Spike protein receptor-binding domain at high titers.


Subject(s)
COVID-19 Vaccines , COVID-19 , Epitopes , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Animals , COVID-19/genetics , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , COVID-19 Vaccines/isolation & purification , COVID-19 Vaccines/pharmacology , Epitopes/genetics , Epitopes/immunology , Epitopes/isolation & purification , Epitopes/pharmacology , Female , Humans , Mice , Mice, Inbred BALB C , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombinant Proteins/isolation & purification , Recombinant Proteins/pharmacology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/isolation & purification , Spike Glycoprotein, Coronavirus/pharmacology
15.
Protein Expr Purif ; 190: 106003, 2022 02.
Article in English | MEDLINE | ID: covidwho-1474960

ABSTRACT

SARS-CoV-2 protein subunit vaccines are currently being evaluated by multiple manufacturers to address the global vaccine equity gap, and need for low-cost, easy to scale, safe, and effective COVID-19 vaccines. In this paper, we report on the generation of the receptor-binding domain RBD203-N1 yeast expression construct, which produces a recombinant protein capable of eliciting a robust immune response and protection in mice against SARS-CoV-2 challenge infections. The RBD203-N1 antigen was expressed in the yeast Pichia pastoris X33. After fermentation at the 5 L scale, the protein was purified by hydrophobic interaction chromatography followed by anion exchange chromatography. The purified protein was characterized biophysically and biochemically, and after its formulation, the immunogenicity was evaluated in mice. Sera were evaluated for their efficacy using a SARS-CoV-2 pseudovirus assay. The RBD203-N1 protein was expressed with a yield of 492.9 ± 3.0 mg/L of fermentation supernatant. A two-step purification process produced a >96% pure protein with a recovery rate of 55 ± 3% (total yield of purified protein: 270.5 ± 13.2 mg/L fermentation supernatant). The protein was characterized to be a homogeneous monomer that showed a well-defined secondary structure, was thermally stable, antigenic, and when adjuvanted on Alhydrogel in the presence of CpG it was immunogenic and induced high levels of neutralizing antibodies against SARS-CoV-2 pseudovirus. The characteristics of the RBD203-N1 protein-based vaccine show that this candidate is another well suited RBD-based construct for technology transfer to manufacturing entities and feasibility of transition into the clinic to evaluate its immunogenicity and safety in humans.


Subject(s)
COVID-19 Vaccines , Gene Expression , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Animals , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/genetics , COVID-19 Vaccines/pharmacology , Humans , Mice , Protein Domains , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacology , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Saccharomyces cerevisiae/chemistry , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/pharmacology
16.
Cancer Discov ; 11(10): 2430-2435, 2021 10.
Article in English | MEDLINE | ID: covidwho-1472319

ABSTRACT

We had previously reported short-term efficacy, immunogenicity, and safety of the BNT162b2 vaccine among cancer patients with solid tumors. We aimed to evaluate these outcomes at six months postvaccination. The study cohort comprised patients who were on treatment during vaccination and throughout six months postvaccination. Serologic tests were performed after second vaccination and six months afterward. An age-matched cohort of health care workers served as controls. Documentation of COVID-19 infection, blood tests, and imaging studies during the study period was reviewed. Participants included 154 patients and 135 controls. Six months postvaccination, 122 (79%) patients were seropositive compared with 114 (84%) controls (P = 0.32). Serology titer dramatically decreased in a similar manner in both cohorts. No COVID-19 cases were documented in controls, and one case occurred in patient cohort. All previously reported adverse effects resolved. Taken together, the pattern of immunogenicity, efficacy, and safety of BNT162b2 in patients with cancer with solid tumors at six months postvaccination resembles that of the general population. SIGNIFICANCE: Evidence regarding efficacy and safety of COVID-19 vaccines in patients with cancer indicate a favorable short-term profile. Immunomodulation due to anticancer treatments may affect immunity and immunogenicity of patients with cancer to the BNT162b2 vaccine over time. Our study sheds light on these long-term outcomes and portrays a trend that resembles the general population.This article is highlighted in the In This Issue feature, p. 2355.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/pharmacology , Neoplasms , Adult , Aged , Aged, 80 and over , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Health Personnel , Humans , Male , Middle Aged , Neoplasms/drug therapy , Neutropenia/chemically induced , Thrombocytopenia/chemically induced , Time-to-Treatment , Vaccination
17.
Proc Natl Acad Sci U S A ; 118(44)2021 11 02.
Article in English | MEDLINE | ID: covidwho-1470027

ABSTRACT

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in over 100 million infections and millions of deaths. Effective vaccines remain the best hope of curtailing SARS-CoV-2 transmission, morbidity, and mortality. The vaccines in current use require cold storage and sophisticated manufacturing capacity, which complicates their distribution, especially in less developed countries. We report the development of a candidate SARS-CoV-2 vaccine that is purely protein based and directly targets antigen-presenting cells. It consists of the SARS-CoV-2 Spike receptor-binding domain (SpikeRBD) fused to an alpaca-derived nanobody that recognizes class II major histocompatibility complex antigens (VHHMHCII). This vaccine elicits robust humoral and cellular immunity against SARS-CoV-2 and its variants. Both young and aged mice immunized with two doses of VHHMHCII-SpikeRBD elicit high-titer binding and neutralizing antibodies. Immunization also induces strong cellular immunity, including a robust CD8 T cell response. VHHMHCII-SpikeRBD is stable for at least 7 d at room temperature and can be lyophilized without loss of efficacy.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19 Vaccines/pharmacology , COVID-19/immunology , COVID-19/prevention & control , Pandemics , SARS-CoV-2/immunology , Amino Acid Sequence , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Antigen-Presenting Cells/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/epidemiology , COVID-19 Vaccines/administration & dosage , Camelids, New World/immunology , Female , Histocompatibility Antigens Class II/immunology , Humans , Immunity, Cellular , Immunity, Humoral , Immunization, Secondary , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Transgenic , Pandemics/prevention & control , Recombinant Fusion Proteins/administration & dosage , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , SARS-CoV-2/genetics , Single-Domain Antibodies/administration & dosage , Single-Domain Antibodies/immunology , Spike Glycoprotein, Coronavirus/administration & dosage , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
19.
Elife ; 102021 10 12.
Article in English | MEDLINE | ID: covidwho-1464010

ABSTRACT

While mRNA vaccines are proving highly efficacious against SARS-CoV-2, it is important to determine how booster doses and prior infection influence the immune defense they elicit, and whether they protect against variants. Focusing on the T cell response, we conducted a longitudinal study of infection-naïve and COVID-19 convalescent donors before vaccination and after their first and second vaccine doses, using a high-parameter CyTOF analysis to phenotype their SARS-CoV-2-specific T cells. Vaccine-elicited spike-specific T cells responded similarly to stimulation by spike epitopes from the ancestral, B.1.1.7 and B.1.351 variant strains, both in terms of cell numbers and phenotypes. In infection-naïve individuals, the second dose boosted the quantity and altered the phenotypic properties of SARS-CoV-2-specific T cells, while in convalescents the second dose changed neither. Spike-specific T cells from convalescent vaccinees differed strikingly from those of infection-naïve vaccinees, with phenotypic features suggesting superior long-term persistence and ability to home to the respiratory tract including the nasopharynx. These results provide reassurance that vaccine-elicited T cells respond robustly to emerging viral variants, confirm that convalescents may not need a second vaccine dose, and suggest that vaccinated convalescents may have more persistent nasopharynx-homing SARS-CoV-2-specific T cells compared to their infection-naïve counterparts.


Vaccination is one of the best ways to prevent severe COVID-19. Two doses of mRNA vaccine protect against serious illness caused by the coronavirus SARS-CoV-2. They do this, in part, by encouraging the immune system to make specialised proteins known as antibodies that recognise the virus. Most of the vaccine research so far has focussed on these antibodies, but they are only one part of the immune response. Vaccines also activate immune cells called T cells. These cells have two main roles, coordinating the immune response and killing cells infected with viruses. It is likely that they play a key role in preventing severe COVID-19. There are many kinds of T cells, each with a different role. Currently, the identity and characteristics of the T cells that protect against COVID-19 is unclear. Different types of T cells have unique proteins on their surface. Examining these proteins can reveal details about how the T cells work, which part of the virus they recognise, and which part of the body they protect. A tool called cytometry by time of flight allows researchers to measure these proteins, one cell at a time. Using this technique, Neidleman, Luo et al. investigated T cells from 11 people before vaccination and after their first and second doses. Five people had never had COVID-19 before, and six had already recovered from COVID-19. Neidleman, Luo et al. found that the T cells recognizing SARS-CoV-2 in the two groups differed. In people who had never had COVID-19 before, the second dose of vaccine improved the quality and quantity of the T cells. The same was not true for people who had already recovered from COVID-19. However, although their T cells did not improve further after a second vaccine dose, they did show signs that they might offer more protection overall. The proteins on the cells suggest that they might last longer, and that they might specifically protect the nose, throat and lungs. Neidleman, Luo et al. also found that, for both groups, T cells activated by vaccination responded in the same way to different variants of the virus. This work highlights the importance of getting both vaccine doses for people who have never had COVID-19. It also suggests that vaccination in people who have had COVID-19 may generate better T cells. Larger studies could show whether these patterns remain true across the wider population. If so, it is possible that delivering vaccines to the nose or throat could boost immunity by mimicking natural infection. This might encourage T cells to make the surface proteins that allow them to home to these areas.


Subject(s)
COVID-19 Vaccines/pharmacology , COVID-19/immunology , SARS-CoV-2/immunology , T-Lymphocytes/drug effects , Vaccines, Synthetic/pharmacology , Adult , Aged , COVID-19/prevention & control , COVID-19/virology , Female , Humans , Immunization, Secondary , Longitudinal Studies , Male , Middle Aged , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Young Adult
20.
EBioMedicine ; 72: 103589, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1433161

ABSTRACT

BACKGROUND: To optimise the use of available SARS-CoV-2 vaccines, some advocate delaying second vaccination for individuals infected within six months. We studied whether post-vaccination immune response is equally potent in individuals infected over six months prior to vaccination. METHODS: We tested serum IgG binding to SARS-CoV-2 spike protein and neutralising capacity in 110 healthcare workers, before and after both BNT162b2 messenger RNA (mRNA) vaccinations. We compared outcomes between participants with more recent infection (n = 18, median two months, IQR 2-3), with infection-vaccination interval over six months (n = 19, median nine months, IQR 9-10), and to those not previously infected (n = 73). FINDINGS: Both recently and earlier infected participants showed comparable humoral immune responses after a single mRNA vaccination, while exceeding those of previously uninfected persons after two vaccinations with 2.5 fold (p = 0.003) and 3.4 fold (p < 0.001) for binding antibody levels, and 6.4 and 7.2 fold for neutralisation titres, respectively (both p < 0.001). The second vaccine dose yielded no further substantial improvement of the humoral response in the previously infected participants (0.97 fold, p = 0.92), while it was associated with a 4 fold increase in antibody binding levels and 18 fold increase in neutralisation titres in previously uninfected participants (both p < 0.001). Adjustment for potential confounding of sex and age did not affect these findings. INTERPRETATION: Delaying the second vaccination in individuals infected up to ten months prior may constitute a more efficient use of limited vaccine supplies. FUNDING: Netherlands Organization for Health Research and Development ZonMw; Corona Research Fund Amsterdam UMC; Bill & Melinda Gates Foundation.


Subject(s)
Antibodies, Viral/blood , Antibody Formation , COVID-19 Vaccines/pharmacology , COVID-19 , SARS-CoV-2/immunology , Adult , COVID-19 Vaccines/therapeutic use , Female , Health Personnel , Humans , Immunity, Humoral , Immunoglobulin G/blood , Male , Middle Aged , Netherlands , Prospective Studies , Time Factors , Treatment Outcome
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