scholarly journals A single-dose live-attenuated YF17D-vectored SARS-CoV2 vaccine candidate

2020 ◽  
Author(s):  
Lorena Sanchez Felipe ◽  
Thomas Vercruysse ◽  
Sapna Sharma ◽  
Ji Ma ◽  
Viktor Lemmens ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Yellow Fever ◽  
Emergency Response ◽  
Neutralizing Antibodies ◽  
Vaccine Candidate ◽  
Th1 Cell ◽  
Cell Mediated Immune Response ◽  
Further Development ◽  
Fast Acting

AbstractThe explosively expanding COVID-19 pandemic urges the development of safe, efficacious and fast-acting vaccines to quench the unrestrained spread of SARS-CoV-2. Several promising vaccine platforms, developed in recent years, are leveraged for a rapid emergency response to COVID-191. We employed the live-attenuated yellow fever 17D (YF17D) vaccine as a vector to express the prefusion form of the SARS-CoV-2 Spike antigen. In mice, the vaccine candidate, tentatively named YF-S0, induces high levels of SARS-CoV-2 neutralizing antibodies and a favorable Th1 cell-mediated immune response. In a stringent hamster SARS-CoV-2 challenge model2, vaccine candidate YF-S0 prevents infection with SARS-CoV-2. Moreover, a single dose confers protection from lung disease in most vaccinated animals even within 10 days. These results warrant further development of YF-S0 as a potent SARS-CoV-2 vaccine candidate.

Cell-mediated immune response in calves to single-dose, trickle, and challenge infections with Fasciola hepatica

2000 ◽  
Vol 88 (1-2) ◽  
pp. 17-34 ◽  
Author(s):  
Kristine Bossaert ◽  
Eric Jacquinet ◽  
Jimmy Saunders ◽  
Fredéric Farnir ◽  
Bertrand Losson
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Fasciola Hepatica ◽  
Cell Mediated Immune Response

scholarly journals Recombinant Mycobacterium paragordonae Expressing SARS-CoV-2 Receptor-Binding Domain as a Vaccine Candidate Against SARS-CoV-2 Infections

2021 ◽  
Vol 12 ◽  
Author(s):  
Byoung-Jun Kim ◽  
Hyein Jeong ◽  
Hyejun Seo ◽  
Mi-Hyun Lee ◽  
Hyun Mu Shin ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Immune Responses ◽  
Receptor Binding ◽  
Humoral Immune Response ◽  
Vaccine Candidate ◽  
Binding Domain ◽  
Receptor Binding Domain ◽  
Live Virus ◽  
Humoral Immune

At present, concerns that the recent global emergence of SARS-CoV-2 variants could compromise the current vaccines have been raised, highlighting the urgent demand for new vaccines capable of eliciting T cell-mediated immune responses, as well as B cell-mediated neutralizing antibody production. In this study, we developed a novel recombinant Mycobacterium paragordonae expressing the SARS-CoV-2 receptor-binding domain (RBD) (rMpg-RBD-7) that is capable of eliciting RBD-specific immune responses in vaccinated mice. The potential use of rMpg-RBD-7 as a vaccine for SARS-CoV-2 infections was evaluated in in vivo using mouse models of two different modules, one for single-dose vaccination and the other for two-dose vaccination. In a single-dose vaccination model, we found that rMpg-RBD-7 versus a heat-killed strain could exert an enhanced cell-mediated immune (CMI) response, as well as a humoral immune response capable of neutralizing the RBD and ACE2 interaction. In a two-dose vaccination model, rMpg-RBD-7 in a two-dose vaccination could also exert a stronger CMI and humoral immune response to neutralize SARS-CoV-2 infections in pseudoviral or live virus infection systems, compared to single dose vaccinations of rMpg-RBD or two-dose RBD protein immunization. In conclusion, our data showed that rMpg-RBD-7 can lead to an enhanced CMI response and humoral immune responses in mice vaccinated with both single- or two-dose vaccination, highlighting its feasibility as a novel vaccine candidate for SARS-CoV-2. To the best of our knowledge, this study is the first in which mycobacteria is used as a delivery system for a SARS-CoV-2 vaccine.

scholarly journals Strong immunogenicity of heterologous prime-boost immunizations with the experimental vaccine GRAd-COV2 and BNT162b2 or ChAdOx1-nCOV19

2021 ◽  
Author(s):  
Chiara Agrati ◽  
Stefania Capone ◽  
Concetta Castilletti ◽  
Eleonora Cimini ◽  
Giulia Matusali ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Neutralizing Antibodies ◽  
Small Sample Size ◽  
Phase 1 ◽  
Vaccination Campaign ◽  
Small Sample ◽  
Vaccine Platform ◽  
Ideal Tool ◽  
Cellular Immune

Here we report on the humoral and cellular immune response in eight volunteers who autonomously chose to adhere to the Italian national COVID-19 vaccination campaign more than 3 months after receiving a single administration GRAd-COV2 vaccine candidate in the context of the phase 1 clinical trial. We observed a clear boost of both binding/neutralizing antibodies as well as T cell responses upon receipt of the heterologous BNT162b2 or ChAdOx1-nCOV19 vaccines. These results, despite the limitation of the small sample size, support the concept that a single-dose of an adenoviral vaccine may represent an ideal tool to effectively prime a balanced immune response, which can be boosted to high levels by a single dose of a different vaccine platform.

scholarly journals Single-dose replicating RNA vaccine induces neutralizing antibodies against SARS-CoV-2 in nonhuman primates

2020 ◽  
Author(s):  
Jesse H. Erasmus ◽  
Amit P. Khandhar ◽  
Alexandra C. Walls ◽  
Emily A. Hemann ◽  
Megan A. O’Connor ◽  
...  
Keyword(s):  
Single Dose ◽  
Neutralizing Antibodies ◽  
Global Economy ◽  
Nonhuman Primates ◽  
Vaccine Candidate ◽  
Scale Up ◽  
Igg Antibody ◽  
Antibody Isotypes ◽  
Rna Replicon

AbstractThe ongoing COVID-19 pandemic, caused by infection with SARS-CoV-2, is having a dramatic and deleterious impact on health services and the global economy. Grim public health statistics highlight the need for vaccines that can rapidly confer protection after a single dose and be manufactured using components suitable for scale-up and efficient distribution. In response, we have rapidly developed repRNA-CoV2S, a stable and highly immunogenic vaccine candidate comprised of an RNA replicon formulated with a novel Lipid InOrganic Nanoparticle (LION) designed to enhance vaccine stability, delivery and immunogenicity. We show that intramuscular injection of LION/repRNA-CoV2S elicits robust anti-SARS-CoV-2 spike protein IgG antibody isotypes indicative of a Type 1 T helper response as well as potent T cell responses in mice. Importantly, a single-dose administration in nonhuman primates elicited antibody responses that potently neutralized SARS-CoV-2. These data support further development of LION/repRNA-CoV2S as a vaccine candidate for prophylactic protection from SARS-CoV-2 infection.

scholarly journals Successful Boosting of a DNA Measles Immunization with an Oral Plant-Derived Measles Virus Vaccine

2002 ◽  
Vol 76 (15) ◽  
pp. 7910-7912 ◽  
Author(s):  
Diane E. Webster ◽  
Michelle L. Cooney ◽  
Zhongjun Huang ◽  
Damien R. Drew ◽  
Ian A. Ramshaw ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Global Health ◽  
Virus Vaccine ◽  
Neutralizing Antibodies ◽  
Measles Virus ◽  
Vaccination Strategy ◽  
Health Concern ◽  
Dna Immunization ◽  
Edible Plant

ABSTRACT Despite eradication attempts, measles remains a global health concern. Here we report results that demonstrate that a single-dose DNA immunization followed by multiple boosters, delivered orally as a plant-derived vaccine, can induce significantly greater quantities of measles virus-neutralizing antibodies than immunization with either DNA or plant-derived vaccines alone. This represents the first demonstration of an enhanced immune response to a prime-boost vaccination strategy combining a DNA vaccine with edible plant technology.

scholarly journals Late-Relapsing Hepatitis after Yellow Fever

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 222 ◽  
Author(s):  
Izabela Maurício Rezende ◽  
Leonardo Soares Pereira ◽  
Jordana Rodrigues Barbosa Fradico ◽  
Marcelo Antônio Pascoal Xavier ◽  
Pedro Augusto Alves ◽  
...  
Keyword(s):  
Immune Response ◽  
Yellow Fever ◽  
Neutralizing Antibodies ◽  
Laboratory Tests ◽  
Cell Damage ◽  
Viral Persistence ◽  
Response Profile ◽  
Liver Transaminases ◽  
Hepatic Cytolysis

One patient presented hyporexia, asthenia, adynamia, and jaundice two months after acute yellow fever (YF) onset; plus laboratory tests indicating hepatic cytolysis and a rebound of alanine and aspartate transaminases, and total and direct bilirubin levels. Laboratory tests discarded autoimmune hepatitis, inflammatory or metabolic liver disease, and new infections caused by hepatotropic agents. Anti-YFV IgM, IgG and neutralizing antibodies were detected in different times, but no viremia. A liver biopsy was collected three months after YF onset and tested positive for YFV antigens and wild-type YFV-RNA (364 RNA-copies/gram/liver). Transaminases and bilirubin levels remained elevated for five months, and the arresting of symptoms persisted for six months after the acute YF onset. Several serum chemokines, cytokines, and growth factors were measured. A similar immune response profile was observed in the earlier phases of the disease, followed by more pronounced changes in the later stages, when transaminases levels returned to normal. The results indicated viral persistence in the liver and continual liver cell damage three months after YF onset and reinforced the need for extended follow-ups of YF patients. Further studies to investigate the role of possible viral persistence and the immune response causing relapsing hepatitis following YF are also necessary.

scholarly journals Comparative Immunomodulatory Evaluation of the Receptor Binding Domain of the SARS-CoV-2 Spike Protein; a Potential Vaccine Candidate Which Imparts Potent Humoral and Th1 Type Immune Response in a Mouse Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Tripti Shrivastava ◽  
Balwant Singh ◽  
Zaigham Abbas Rizvi ◽  
Rohit Verma ◽  
Sandeep Goswami ◽  
...  
Keyword(s):  
Immune Response ◽  
Receptor Binding ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vaccine Candidate ◽  
Unmet Need ◽  
Binding Domain ◽  
Spike Protein ◽  
Cell Immune Response ◽  
Receptor Binding Domain

The newly emerged novel coronavirus, SARS-CoV-2, the causative agent of COVID-19 has proven to be a threat to the human race globally, thus, vaccine development against SARS-CoV-2 is an unmet need driving mass vaccination efforts. The receptor binding domain of the spike protein of this coronavirus has multiple neutralizing epitopes and is associated with viral entry. Here we have designed and characterized the SARS-CoV-2 spike protein fragment 330-526 as receptor binding domain 330-526 (RBD330-526) with two native glycosylation sites (N331 and N343); as a potential subunit vaccine candidate. We initially characterized RBD330-526 biochemically and investigated its thermal stability, humoral and T cell immune response of various RBD protein formulations (with or without adjuvant) to evaluate the inherent immunogenicity and immunomodulatory effect. Our result showed that the purified RBD immunogen is stable up to 72 h, without any apparent loss in affinity or specificity of interaction with the ACE2 receptor. Upon immunization in mice, RBD generates a high titer humoral response, elevated IFN-γ producing CD4+ cells, cytotoxic T cells, and robust neutralizing antibodies against live SARS-CoV-2 virus. Our results collectively support the potential of RBD330-526 as a promising vaccine candidate against SARS-CoV-2.

scholarly journals Vaccine Breakthrough Infections by SARS-CoV-2 Variants after ChAdOx1 nCoV-19 Vaccination in Healthcare Workers

Vaccines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Pratibha Kale ◽  
Ekta Gupta ◽  
Chhagan Bihari ◽  
Niharika Patel ◽  
Sheetalnath Rooge ◽  
...  
Keyword(s):  
Immune Response ◽  
Single Dose ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Humoral Immune Response ◽  
Neutralizing Antibodies ◽  
Healthcare Workers ◽  
Genomic Analysis ◽  
Whole Genome ◽  
Humoral Immune

This study elucidated the clinical, humoral immune response and genomic analysis of vaccine breakthrough (VBT) infections after ChAdOx1 nCoV-19/Covishield vaccine in healthcare workers (HCWs). Amongst 1858 HCWs, 1639 had received either two doses (1346) or a single dose (293) of ChAdOx1 nCoV-19 vaccine. SARS-CoV-2 IgG antibodies and neutralizing antibodies were measured in the vaccinated group and the development of SARS-CoV-2 infection was monitored.Forty-six RT-PCR positive samples from the 203 positive samples were subjected to whole genome sequencing (WGS). Of the 203 (10.92%) infected HCWs, 21.46% (47/219) were non-vaccinated, which was significantly more than 9.52% (156/1639) who were vaccinated and infection was higher in doctors and nurses. Unvaccinated HCWs had 1.57 times higher risk compared to partially vaccinated HCWs and 2.49 times higher risk than those who were fully vaccinated.The partially vaccinated were at higher risk than the fully vaccinated (RR 1.58). Antibody non-response was seen in 3.44% (4/116), low antibody levels in 15.51% (18/116) and medium levels were found in 81.03% (94/116). Fully vaccinated HCWs had a higher antibody response at day 42 than those who were partially vaccinated (8.96 + 4.00 vs. 7.17 + 3.82). Whole genome sequencing of 46 samples revealed that the Delta variant (B.1.617.2) was predominant (69.5%). HCWs who had received two doses of vaccine showed better protection from mild, moderate, or severe infection, with a higher humoral immune response than those who had received a single dose. The genomic analysis revealed the predominance of the Delta variant (B.1.617.2) in the VBT infections.

scholarly journals Development of an mRNA-LNP Vaccine against SARS-CoV-2: Evaluation of Immune Response in Mouse and Rhesus Macaque

Vaccines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1007
Author(s):  
Alireza Naderi Sohi ◽  
Jafar Kiani ◽  
Ehsan Arefian ◽  
Arezou Khosrojerdi ◽  
Zahra Fekrirad ◽  
...  
Keyword(s):  
Immune Response ◽  
Rhesus Macaque ◽  
Neutralizing Antibodies ◽  
Nucleoside Analogs ◽  
In Vitro Transcription ◽  
In Vitro Cytotoxicity ◽  
Th1 Cell ◽  
Ethanol Injection ◽  
Significant Augmentation

Among the vaccines have been developed thus far against SARS-CoV-2, the mRNA-based ones have demonstrated more promising results regarding both safety and efficacy. Two remarkable features of the mRNA vaccines introduced by the Pfizer/BioNTech and Moderna companies are the use of (N1-methyl-pseudouridine-) modified mRNA and the microfluidics-based production of lipid nanoparticles (LNPs) as the carrier. In the present study, except Anti-Reverse Cap Analog (ARCA), no other nucleoside analogs were employed to synthesize Spike-encoding mRNA using the in vitro transcription (IVT) method. Furthermore, LNPs were prepared via the ethanol injection method commonly used for liposome formation as an alternative for microfluidics-based approaches. The produced mRNA-LNP vaccine was evaluated for nanoparticles characteristics, encapsulation and transfection efficiencies, in vitro cytotoxicity as well as stability and storability. The safety of vaccine was assessed in Balb/c mice injected with mRNA-LNPs containing 10 µg of spike-encoding mRNA. Eventually, the vaccine efficacy in inducing an immune response against SARS-CoV-2 was studied in Balb/c and C57BL/6 mice (received either 1 or 10 µg of mRNA) as well as in rhesus macaque monkeys (infused with mRNA-LNPs containing 100 µg of mRNA). The ELISA and virus neutralizing test (VNT) results showed a significant augmentation in the level of neutralizing antibodies against SARS-CoV-2. Moreover, the ELISA assay showed virus-specific IFN-γ secretion in immunized mice as a marker of TH1 cell-based immune response, whereas favorably no change in the production of IL-4 was detected.

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