scholarly journals VLP-Based COVID-19 Vaccines: An Adaptable Technology against the Threat of New Variants

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1409
Author(s):  
Wasim A. Prates-Syed ◽  
Lorena C. S. Chaves ◽  
Karin P. Crema ◽  
Larissa Vuitika ◽  
Aline Lira ◽  
...  
Keyword(s):  
Immune Responses ◽  
Immune Evasion ◽  
Convergent Evolution ◽  
Vaccine Development ◽  
Receptor Binding Domain ◽  
Vaccine Platform ◽  
Cellular Immune Responses ◽  
Alpha Beta ◽  
Cellular Immune ◽  
Financial Losses

Virus-like particles (VLPs) are a versatile, safe, and highly immunogenic vaccine platform. Recently, there are developmental vaccines targeting SARS-CoV-2, the causative agent of COVID-19. The COVID-19 pandemic affected humanity worldwide, bringing out incomputable human and financial losses. The race for better, more efficacious vaccines is happening almost simultaneously as the virus increasingly produces variants of concern (VOCs). The VOCs Alpha, Beta, Gamma, and Delta share common mutations mainly in the spike receptor-binding domain (RBD), demonstrating convergent evolution, associated with increased transmissibility and immune evasion. Thus, the identification and understanding of these mutations is crucial for the production of new, optimized vaccines. The use of a very flexible vaccine platform in COVID-19 vaccine development is an important feature that cannot be ignored. Incorporating the spike protein and its variations into VLP vaccines is a desirable strategy as the morphology and size of VLPs allows for better presentation of several different antigens. Furthermore, VLPs elicit robust humoral and cellular immune responses, which are safe, and have been studied not only against SARS-CoV-2 but against other coronaviruses as well. Here, we describe the recent advances and improvements in vaccine development using VLP technology.

scholarly journals mRNA vaccination in people over 80 years of age induces strong humoral immune responses against SARS-CoV-2 with cross neutralization of P.1 Brazilian variant

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Helen Parry ◽  
Gokhan Tut ◽  
Rachel Bruton ◽  
Sian Faustini ◽  
Christine Stephens ◽  
...  
Keyword(s):  
Immune Responses ◽  
Cellular Response ◽  
Humoral Response ◽  
Antibody Responses ◽  
Vaccine Platform ◽  
Humoral Immune ◽  
Vaccine Responses ◽  
Cellular Immune Responses ◽  
Humoral Immune Responses ◽  
Cellular Immune

Age is the major risk factor for mortality after SARS-CoV-2 infection and older people have received priority consideration for COVID-19 vaccination. However, vaccine responses are often suboptimal in this age group and few people over the age of 80 years were included in vaccine registration trials. We determined the serological and cellular response to spike protein in 100 people aged 80–96 years at 2 weeks after the second vaccination with the Pfizer BNT162b2 mRNA vaccine. Antibody responses were seen in every donor with high titers in 98%. Spike-specific cellular immune responses were detectable in only 63% and correlated with humoral response. Previous SARS-CoV-2 infection substantially increased antibody responses after one vaccine and antibody and cellular responses remained 28-fold and 3-fold higher, respectively, after dual vaccination. Post-vaccine sera mediated strong neutralization of live Victoria infection and although neutralization titers were reduced 14-fold against the P.1 variant first discovered in Brazil they remained largely effective. These data demonstrate that the mRNA vaccine platform delivers strong humoral immunity in people up to 96 years of age and retains broad efficacy against the P.1 variant of concern.

scholarly journals A Combined Adjuvant TF–Al Consisting of TFPR1 and Aluminum Hydroxide Augments Strong Humoral and Cellular Immune Responses in Both C57BL/6 and BALB/c Mice

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1408
Author(s):  
Qiao Li ◽  
Zhihua Liu ◽  
Yi Liu ◽  
Chen Liang ◽  
Jiayi Shu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Vaccine Development ◽  
Inbred Mouse ◽  
Effective Vaccine ◽  
Mouse Strains ◽  
Cellular Immune Responses ◽  
Recombinant Hbsag ◽  
Cellular Immune

TFPR1 is a novel adjuvant for protein and peptide antigens, which has been demonstrated in BALB/c mice in our previous studies; however, its adjuvanticity in mice with different genetic backgrounds remains unknown, and its adjuvanticity needs to be improved to fit the requirements for various vaccines. In this study, we first compared the adjuvanticity of TFPR1 in two commonly used inbred mouse strains, BALB/c and C57BL/6 mice, in vitro and in vivo, and demonstrated that TFPR1 activated TLR2 to exert its immune activity in vivo. Next, to prove the feasibility of TFPR1 acting as a major component of combined adjuvants, we prepared a combined adjuvant, TF–Al, by formulating TFPR1 and alum at a certain ratio and compared its adjuvanticity with that of TFPR1 and alum alone using OVA and recombinant HBsAg as model antigens in both BALB/c and C57BL/6 mice. Results showed that TFPR1 acts as an effective vaccine adjuvant in both BALB/c mice and C57BL/6 mice, and further demonstrated the role of TLR2 in the adjuvanticity of TFPR1 in vivo. In addition, we obtained a novel combined adjuvant, TF–Al, based on TFPR1, which can augment antibody and cellular immune responses in mice with different genetic backgrounds, suggesting its promise for vaccine development in the future.

scholarly journals Characterization of the Immune Response of MERS-CoV Vaccine Candidates Derived from Two Different Vectors in Mice

Viruses ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 125 ◽  
Author(s):  
Entao Li ◽  
Feihu Yan ◽  
Pei Huang ◽  
Hang Chi ◽  
Shengnan Xu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Antibody Response ◽  
Rabies Virus ◽  
Vaccine Development ◽  
Vaccine Candidate ◽  
Viral Vector ◽  
Vaccine Vector ◽  
Vaccine Candidates ◽  
Cellular Immune Responses ◽  
Cellular Immune

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.

scholarly journals Induction of Broad-Based Immunity and Protective Efficacy by Self-amplifying mRNA Vaccines Encoding Influenza Virus Hemagglutinin

2015 ◽  
Vol 90 (1) ◽  
pp. 332-344 ◽  
Author(s):  
Michela Brazzoli ◽  
Diletta Magini ◽  
Alessandra Bonci ◽  
Scilla Buccato ◽  
Cinzia Giovani ◽  
...  
Keyword(s):  
T Cells ◽  
Influenza Virus ◽  
Immune Responses ◽  
Upper Respiratory Tract ◽  
Vaccine Platform ◽  
Major Health Problem ◽  
Cellular Immune Responses ◽  
Influenza Virus Hemagglutinin ◽  
Cellular Immune ◽  
The Impact

ABSTRACTSeasonal influenza is a vaccine-preventable disease that remains a major health problem worldwide, especially in immunocompromised populations. The impact of influenza disease is even greater when strains drift, and influenza pandemics can result when animal-derived influenza virus strains combine with seasonal strains. In this study, we used the SAM technology and characterized the immunogenicity and efficacy of a self-amplifying mRNA expressing influenza virus hemagglutinin (HA) antigen [SAM(HA)] formulated with a novel oil-in-water cationic nanoemulsion. We demonstrated that SAM(HA) was immunogenic in ferrets and facilitated containment of viral replication in the upper respiratory tract of influenza virus-infected animals. In mice, SAM(HA) induced potent functional neutralizing antibody and cellular immune responses, characterized by HA-specific CD4 T helper 1 and CD8 cytotoxic T cells. Furthermore, mice immunized with SAM(HA) derived from the influenza A virus A/California/7/2009 (H1N1) strain (Cal) were protected from a lethal challenge with the heterologous mouse-adapted A/PR/8/1934 (H1N1) virus strain (PR8). Sera derived from SAM(H1-Cal)-immunized animals were not cross-reactive with the PR8 virus, whereas cross-reactivity was observed for HA-specific CD4 and CD8 T cells. Finally, depletion of T cells demonstrated that T-cell responses were essential in mediating heterologous protection. If the SAM vaccine platform proves safe, well tolerated, and effective in humans, the fully synthetic SAM vaccine technology could provide a rapid response platform to control pandemic influenza.IMPORTANCEIn this study, we describe protective immune responses in mice and ferrets after vaccination with a novel HA-based influenza vaccine. This novel type of vaccine elicits both humoral and cellular immune responses. Although vaccine-specific antibodies are the key players in mediating protection from homologous influenza virus infections, vaccine-specific T cells contribute to the control of heterologous infections. The rapid production capacity and the synthetic origin of the vaccine antigen make the SAM platform particularly exploitable in case of influenza pandemic.

scholarly journals Humoral and cellular immunity and the safety of COVID-19 vaccines: a summary of data published by 21 May 2021

2021 ◽  
Vol 33 (10) ◽  
pp. 529-540
Author(s):  
Kun Xu ◽  
Lianpan Dai ◽  
George F Gao
Keyword(s):  
Immune Responses ◽  
Viral Genome ◽  
Vaccine Development ◽  
Published Data ◽  
Humoral And Cellular Immunity ◽  
Cellular Immune Responses ◽  
Rapid Responses ◽  
Study Results ◽  
Protection Efficacy ◽  
Cellular Immune

Abstract Coronavirus disease 2019 (COVID-19) has caused millions of deaths, and serious consequences to public health, economies and societies. Rapid responses in vaccine development have taken place since the isolation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the release of the viral genome sequence. By 21 May 2021, 101 vaccines were under clinical trials, and published data were available for 18 of them. Clinical study results from some vaccines indicated good immunogenicity and acceptable reactogenicity. Here, we focus on these 18 vaccines that had published clinical data to dissect the induced humoral and cellular immune responses as well as their safety profiles and protection efficacy.

scholarly journals Cellular and Humoral Immunogenicity of a Candidate DNA Vaccine Expressing SARS-CoV-2 Spike Subunit 1

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 852
Author(s):  
Khalid A. Alluhaybi ◽  
Rahaf H. Alharbi ◽  
Rowa Y. Alhabbab ◽  
Najwa D. Aljehani ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Immune Responses ◽  
Dna Vaccine ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Specific Igg ◽  
Cellular Immune ◽  
Different Doses

The urgent need for effective, safe and equitably accessible vaccines to tackle the ongoing spread of COVID-19 led researchers to generate vaccine candidates targeting varieties of immunogens of SARS-CoV-2. Because of its crucial role in mediating binding and entry to host cell and its proven safety profile, the subunit 1 (S1) of the spike protein represents an attractive immunogen for vaccine development. Here, we developed and assessed the immunogenicity of a DNA vaccine encoding the SARS-CoV-2 S1. Following in vitro confirmation and characterization, the humoral and cellular immune responses of our vaccine candidate (pVAX-S1) was evaluated in BALB/c mice using two different doses, 25 µg and 50 µg. Our data showed high levels of SARS-CoV-2 specific IgG and neutralizing antibodies in mice immunized with three doses of pVAX-S1. Analysis of the induced IgG subclasses showed a Th1-polarized immune response, as demonstrated by the significant elevation of spike-specific IgG2a and IgG2b, compared to IgG1. Furthermore, we found that the immunization of mice with three doses of 50 µg of pVAX-S1 could elicit significant memory CD4+ and CD8+ T cell responses. Taken together, our data indicate that pVAX-S1 is immunogenic and safe in mice and is worthy of further preclinical and clinical evaluation.

scholarly journals Development of a Multi-Antigenic SARS-CoV-2 Vaccine Using a Synthetic Poxvirus Platform

2020 ◽  
Author(s):  
Flavia Chiuppesi ◽  
Marcela d’Alincourt Salazar ◽  
Heidi Contreras ◽  
Vu Nguyen ◽  
Joy Martinez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Candidate ◽  
Vaccine Platform ◽  
Synthetic Dna ◽  
Cellular Immune Responses ◽  
Global Pandemic ◽  
Immunodominant Antigens ◽  
Cellular Immune

Abstract Modified Vaccinia Ankara (MVA) is a highly attenuated poxvirus vector that is widely used to develop vaccines for infectious diseases and cancer. We developed a novel vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we used this novel vaccine platform to rapidly produce fully synthetic MVA (sMVA) vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. Mice immunized with these sMVA vectors developed robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a novel vaccine platform based on synthetic DNA to efficiently generate recombinant MVA vectors and to rapidly develop a multi-antigenic poxvirus-based SARS-CoV-2 vaccine candidate.

scholarly journals Development of a multi-antigenic SARS-CoV-2 vaccine candidate using a synthetic poxvirus platform

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Flavia Chiuppesi ◽  
Marcela d’Alincourt Salazar ◽  
Heidi Contreras ◽  
Vu H. Nguyen ◽  
Joy Martinez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Candidate ◽  
Vaccine Platform ◽  
Synthetic Dna ◽  
Cellular Immune Responses ◽  
Global Pandemic ◽  
Immunodominant Antigens ◽  
Cellular Immune

AbstractModified Vaccinia Ankara (MVA) is a highly attenuated poxvirus vector that is widely used to develop vaccines for infectious diseases and cancer. We demonstrate the construction of a vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we use this vaccine platform to rapidly produce fully synthetic MVA (sMVA) vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. We show that mice immunized with these sMVA vectors develop robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a vaccine platform based on synthetic DNA to efficiently generate recombinant MVA vectors and to rapidly develop a multi-antigenic poxvirus-based SARS-CoV-2 vaccine candidate.

scholarly journals Strain-Dependent Cellular Immune Responses in Cattle following Escherichia coli O157:H7 Colonization

2014 ◽  
Vol 82 (12) ◽  
pp. 5117-5131 ◽  
Author(s):  
Alexander Corbishley ◽  
Nur Indah Ahmad ◽  
Kirsty Hughes ◽  
Michael R. Hutchings ◽  
Sean P. McAteer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
T Cells ◽  
Immune Responses ◽  
Vaccine Development ◽  
Phage Type ◽  
Γδ T Cells ◽  
Cellular Immune Responses ◽  
Ifn Γ ◽  
Cellular Immune ◽  
Strain Dependent

ABSTRACTEnterohemorrhagicEscherichia coli(EHEC) O157:H7 causes hemorrhagic diarrhea and potentially fatal renal failure in humans. Ruminants are considered to be the primary reservoir for human infection. Vaccines that reduce shedding in cattle are only partially protective, and their underlying protective mechanisms are unknown. Studies investigating the response of cattle to colonization generally focus on humoral immunity, leaving the role of cellular immunity unclear. To inform future vaccine development, we studied the cellular immune responses of cattle during EHEC O157:H7 colonization. Calves were challenged either with a phage type 21/28 (PT21/28) strain possessing the Shiga toxin 2a (Stx2a) and Stx2c genes or with a PT32 strain possessing the Stx2c gene only. T-helper cell-associated transcripts at the terminal rectum were analyzed by reverse transcription-quantitative PCR (RT-qPCR). Induction of gamma interferon (IFN-γ) and T-bet was observed with peak expression of both genes at 7 days in PT32-challenged calves, while upregulation was delayed, peaking at 21 days, in PT21/28-challenged calves. Cells isolated from gastrointestinal lymph nodes demonstrated antigen-specific proliferation and IFN-γ release in response to type III secreted proteins (T3SPs); however, responsiveness was suppressed in cells isolated from PT32-challenged calves. Lymph node cells showed increased expression of the proliferation marker Ki67 in CD4+T cells from PT21/28-challenged calves, NK cells from PT32-challenged calves, and CD8+and γδ T cells from both PT21/28- and PT32-challenged calves followingex vivorestimulation with T3SPs. This study demonstrates that cattle mount cellular immune responses during colonization with EHEC O157:H7, the temporality of which is strain dependent, with further evidence of strain-specific immunomodulation.

scholarly journals Development of a Synthetic Poxvirus-Based SARS-CoV-2 Vaccine

2020 ◽  
Author(s):  
Flavia Chiuppesi ◽  
Marcela d’Alincourt Salazar ◽  
Heidi Contreras ◽  
Vu H Nguyen ◽  
Joy Martinez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Candidate ◽  
Vaccine Platform ◽  
Synthetic Dna ◽  
Cellular Immune Responses ◽  
Global Pandemic ◽  
Immunodominant Antigens ◽  
Cellular Immune

AbstractModified Vaccinia Ankara (MVA) is a highly attenuated poxvirus vector that is widely used to develop vaccines for infectious diseases and cancer. We developed a novel vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we used this novel vaccine platform to rapidly produce fully synthetic MVA (sMVA) vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. Mice immunized with these sMVA vectors developed robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a novel vaccine platform based on synthetic DNA to efficiently generate recombinant MVA vectors and to rapidly develop a multi-antigenic poxvirus-based SARS-CoV-2 vaccine candidate.

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