scholarly journals Comparison of Mucosal and Intramuscular Immunization against SARS-CoV-2 with Replication-Defective and Replicating Single-cycle Adenovirus Vaccines

2021 ◽  
Author(s):  
Michael A Barry ◽  
Haley Mudrick ◽  
Erin McGlinch ◽  
Brian Parrett ◽  
Jack Hemsath ◽  
...  
Keyword(s):  
The Body ◽  
Antibody Responses ◽  
Spike Protein ◽  
Mucosal Protection ◽  
Single Cycle ◽  
Cell Responses ◽  
Binding Domains ◽  
Mucosal Surfaces ◽  
Mucosal Vaccines ◽  
Mucosal Pathogens

SARS-CoV-2 enters the body at mucosal surfaces, such as the nose and lungs. These events involve a small number of virions at these mucosal barriers and are therefore a strategic point to stop a COVID-19 infection before it starts. Despite this, most vaccines against COVID-19 are being injected into the muscle where they will not generate the highest levels of mucosal protection. The vaccines that are approved for use in humans are all replication-defective (RD) mRNA, DNA, or adenovirus (Ad) vaccines that do not amplify antigen transgenes. We developed single cycle adenovirus (SC-Ad) vectors that replicate antigen genes up to 10,000-fold in human cells, but that are disabled from producing infectious Ad particles. We show here that SC-Ad expressing the full-length SARS-CoV-2 spike protein produces 100-fold more spike protein than a matched RD-Ad-Spike vector. When Ad-permissive hamsters were immunized with these vaccines by intranasal (IN) or intramuscular (IM) routes, SC-Ad produced significantly stronger antibody responses as compared to RD-Ad against the spike protein that rose over 14 weeks after one immunization. Single IN or IM immunizations generated significant antibody responses in serum and in bronchoalveolar lavages (BALs). IN priming, but not IM priming, generated HLA-restricted CD8 T cell responses in BALs. SC-Ad-Spike generated antibodies that retain binding to spike receptor binding domains (RBDs) with mutations from new viral variants. These data suggest empowering the genomes of gene-based vaccines with the ability to amplify antigen genes can increase potency. This may be particularly advantageous when applying mucosal vaccines to combat mucosal pathogens like SARS-CoV-2.

scholarly journals A Replicating Single-Cycle Adenovirus Vaccine Effective against Clostridium difficile

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 470
Author(s):  
William E. Matchett ◽  
Stephanie Anguiano-Zarate ◽  
Goda Baddage Rakitha Malewana ◽  
Haley Mudrick ◽  
Melissa Weldy ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Neutralizing Antibodies ◽  
Antibody Responses ◽  
Complete Protection ◽  
Single Cycle ◽  
Toxin B ◽  
Toxin Binding ◽  
Binding Domains ◽  
Binding Antibody

Clostridium difficile causes nearly 500,000 infections and nearly 30,000 deaths each year in the U.S., which is estimated to cost $4.8 billion. C. difficile infection (CDI) arises from bacteria colonizing the large intestine and releasing two toxins, toxin A (TcdA) and toxin B (TcdB). Generating humoral immunity against C. difficile’s toxins provides protection against primary infection and recurrence. Thus, a vaccine may offer the best opportunity for sustained, long-term protection. We developed a novel single-cycle adenovirus (SC-Ad) vaccine against C. difficile expressing the receptor-binding domains from TcdA and TcdB. The single immunization of mice generated sustained toxin-binding antibody responses and protected them from lethal toxin challenge for up to 38 weeks. Immunized Syrian hamsters produced significant toxin-neutralizing antibodies that increased over 36 weeks. Single intramuscular immunization provided complete protection against lethal BI/NAP1/027 spore challenge 45 weeks later. These data suggest that this replicating vaccine may prove useful against CDI in humans.

scholarly journals The mucosal barrier: Protective frontier to the outside world

2011 ◽  
Vol 33 (4) ◽  
pp. 10-15
Author(s):  
Tony Corfield
Keyword(s):  
External Environment ◽  
The Body ◽  
Mucosal Barrier ◽  
Mucosal Protection ◽  
Protective Barrier ◽  
Pathological Conditions ◽  
Mucosal Surfaces ◽  
Microbiological Agents ◽  
Gut Metabolism

The mucosal surfaces throughout the body are designed to provide an interface which can tolerate and protect at the same time. They need to screen the external environment and select for transport of required factors, such as nutrients from the diet, interact with the microflora present – taking benefit from those commensal strains while resisting pathogens, act as a milieu for an assortment of antimicrobial molecules and also combat attack from aggressive chemical and other microbiological agents. The system must be dynamic so that a continuous intact protective barrier is maintained at all times. Failure of the barrier leads to pathological conditions, and abnormal barrier components are among well known biomarkers for mucosal diseases. This brief review highlights some of the aspects relating to gut metabolism and mucosal protection.

scholarly journals Children develop robust and sustained cross-reactive spike-specific immune responses to SARS-CoV-2 infection

2021 ◽  
Author(s):  
Alexander C. Dowell ◽  
Megan S. Butler ◽  
Elizabeth Jinks ◽  
Gokhan Tut ◽  
Tara Lancaster ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Cellular Immunity ◽  
Cellular Responses ◽  
Antibody Responses ◽  
Spike Protein ◽  
Cell Responses ◽  
Clinical Protection ◽  
Pediatric Vaccination ◽  
Insight Into

AbstractSARS-CoV-2 infection is generally mild or asymptomatic in children but a biological basis for this outcome is unclear. Here we compare antibody and cellular immunity in children (aged 3–11 years) and adults. Antibody responses against spike protein were high in children and seroconversion boosted responses against seasonal Beta-coronaviruses through cross-recognition of the S2 domain. Neutralization of viral variants was comparable between children and adults. Spike-specific T cell responses were more than twice as high in children and were also detected in many seronegative children, indicating pre-existing cross-reactive responses to seasonal coronaviruses. Importantly, children retained antibody and cellular responses 6 months after infection, whereas relative waning occurred in adults. Spike-specific responses were also broadly stable beyond 12 months. Therefore, children generate robust, cross-reactive and sustained immune responses to SARS-CoV-2 with focused specificity for the spike protein. These findings provide insight into the relative clinical protection that occurs in most children and might help to guide the design of pediatric vaccination regimens.

scholarly journals Induction of cross-reactive antibody responses against the RBD domain of the spike protein of SARS-CoV-2 by commensal microbiota

2021 ◽  
Author(s):  
Justus Ninnemann ◽  
Lisa Budzinski ◽  
Marina Bondareva ◽  
Mario Witkowski ◽  
Stefan Angermair ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Antibody Responses ◽  
Commensal Bacteria ◽  
Spike Protein ◽  
Secretory Iga ◽  
Host Proteins ◽  
Commensal Microbiota ◽  
Mucosal Surfaces ◽  
Iga Antibodies ◽  
Reactive Antibody

The commensal microflora is a source for multiple antigens that may induce cross-reactive antibodies against host proteins and pathogens. However, whether commensal bacteria can induce cross-reactive antibodies against SARS-CoV-2 remains unknown. Here we report that several commensal bacteria contribute to the generation of cross-reactive IgA antibodies against the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein. We identified SARS-CoV-2 unexposed individuals with RBD-binding IgA antibodies at their mucosal surfaces. Conversely, neutralising monoclonal anti-RBD antibodies recognised distinct commensal bacterial species. Some of these bacteria, such as Streptococcus salivarius, induced a cross-reactive anti-RBD antibodies upon supplementation in mice. Conversely, severely ill COVID-19 patients showed reduction of Streptococcus and Veillonella in their oropharynx and feces and a reduction of anti-RBD IgA at mucosal surfaces. Altogether, distinct microbial species of the human microbiota can induce secretory IgA antibodies cross-reactive for the RBD of SARS-CoV-2.

scholarly journals Oral insulin immunotherapy in children at risk for type 1 diabetes in a randomised controlled trial

Diabetologia ◽  
2021 ◽  
Author(s):  
Robin Assfalg ◽  
Jan Knoop ◽  
Kristi L. Hoffman ◽  
Markus Pfirrmann ◽  
Jose Maria Zapardiel-Gonzalo ◽  
...  
Keyword(s):  
Immune Response ◽  
Type 1 Diabetes ◽  
Randomised Controlled Trial ◽  
Primary Outcome ◽  
Controlled Trial ◽  
Antibody Responses ◽  
Oral Insulin ◽  
Cell Responses ◽  
Randomised Controlled

Abstract Aims/hypothesis Oral administration of antigen can induce immunological tolerance. Insulin is a key autoantigen in childhood type 1 diabetes. Here, oral insulin was given as antigen-specific immunotherapy before the onset of autoimmunity in children from age 6 months to assess its safety and immune response actions on immunity and the gut microbiome. Methods A phase I/II randomised controlled trial was performed in a single clinical study centre in Germany. Participants were 44 islet autoantibody-negative children aged 6 months to 2.99 years who had a first-degree relative with type 1 diabetes and a susceptible HLA DR4-DQ8-containing genotype. Children were randomised 1:1 to daily oral insulin (7.5 mg with dose escalation to 67.5 mg) or placebo for 12 months using a web-based computer system. The primary outcome was immune efficacy pre-specified as induction of antibody or T cell responses to insulin and measured in a central treatment-blinded laboratory. Results Randomisation was performed in 44 children. One child in the placebo group was withdrawn after the first study visit and data from 22 insulin-treated and 21 placebo-treated children were analysed. Oral insulin was well tolerated with no changes in metabolic variables. Immune responses to insulin were observed in children who received both insulin (54.5%) and placebo (66.7%), and the trial did not demonstrate an effect on its primary outcome (p = 0.54). In exploratory analyses, there was preliminary evidence that the immune response and gut microbiome were modified by the INS genotype Among children with the type 1 diabetes-susceptible INS genotype (n = 22), antibody responses to insulin were more frequent in insulin-treated (72.7%) as compared with placebo-treated children (18.2%; p = 0.03). T cell responses to insulin were modified by treatment-independent inflammatory episodes. Conclusions/interpretation The study demonstrated that oral insulin immunotherapy in young genetically at-risk children was safe, but was not associated with an immune response as predefined in the trial primary outcome. Exploratory analyses suggested that antibody responses to oral insulin may occur in children with a susceptible INS genotype, and that inflammatory episodes may promote the activation of insulin-responsive T cells. Trial registration Clinicaltrials.gov NCT02547519 Funding The main funding source was the German Center for Diabetes Research (DZD e.V.) Graphical abstract

scholarly journals Immunization with RBD-P2 and N protects against SARS-CoV-2 in nonhuman primates

2021 ◽  
Vol 7 (22) ◽  
pp. eabg7156
Author(s):  
So-Hee Hong ◽  
Hanseul Oh ◽  
Yong Wook Park ◽  
Hye Won Kwak ◽  
Eun Young Oh ◽  
...  
Keyword(s):  
Nucleocapsid Protein ◽  
Nonhuman Primates ◽  
Vaccine Candidate ◽  
Statistical Significance ◽  
Neutralizing Antibody ◽  
Spike Protein ◽  
Vaccine Candidates ◽  
Cell Responses ◽  
Antibody Levels ◽  
Further Development

Since the emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), various vaccines are being developed, with most vaccine candidates focusing on the viral spike protein. Here, we developed a previously unknown subunit vaccine comprising the receptor binding domain (RBD) of the spike protein fused with the tetanus toxoid epitope P2 (RBD-P2) and tested its efficacy in rodents and nonhuman primates (NHPs). We also investigated whether the SARS-CoV-2 nucleocapsid protein (N) could increase vaccine efficacy. Immunization with N and RBD-P2 (RBDP2/N) + alum increased T cell responses in mice and neutralizing antibody levels in rats compared with those obtained using RBD-P2 + alum. Furthermore, in NHPs, RBD-P2/N + alum induced slightly faster SARS-CoV-2 clearance than that induced by RBD-P2 + alum, albeit without statistical significance. Our study supports further development of RBD-P2 as a vaccine candidate against SARS-CoV-2. Also, it provides insights regarding the use of N in protein-based vaccines against SARS-CoV-2.

scholarly journals Induction of Mucosal Protection against Primary, Heterologous Simian Immunodeficiency Virus by a DNA Vaccine

2002 ◽  
Vol 76 (7) ◽  
pp. 3309-3317 ◽  
Author(s):  
Deborah Heydenburg Fuller ◽  
Premeela A. Rajakumar ◽  
Lawrence A. Wilson ◽  
Anita M. Trichel ◽  
James T. Fuller ◽  
...  
Keyword(s):  
Simian Immunodeficiency Virus ◽  
Dna Vaccine ◽  
Dna Sequences ◽  
Serum Antibody ◽  
Antibody Responses ◽  
Effective Vaccine ◽  
Lymphoid Tissues ◽  
Mucosal Protection ◽  
Mucosal Transmission ◽  
Immunodeficiency Virus

ABSTRACT An effective vaccine against human immunodeficiency virus (HIV) should protect against mucosal transmission of genetically divergent isolates. As a safe alternative to live attenuated vaccines, the immunogenicity and protective efficacy of a DNA vaccine containing simian immunodeficiency virus (SIV) strain 17E-Fr (SIV/17E-Fr) gag-pol-env was analyzed in rhesus macaques. Significant levels of cytotoxic T lymphocytes (CTL), but low to undetectable serum antibody responses, were observed following multiple immunizations. SIV-specific mucosal antibodies and CTL were also detected in rectal washes and gut-associated lymphoid tissues, respectively. Vaccinated and naive control monkeys were challenged intrarectally with SIV strain DeltaB670 (SIV/DeltaB670), a primary isolate whose env is 15% dissimilar to that of the vaccine strain. Four of seven vaccinees were protected from infection as determined by the inability to identify viral RNA or DNA sequences in the peripheral blood and the absence of anamnestic antibody responses postchallenge. This is the first report of mucosal protection against a primary pathogenic, heterologous isolate of SIV by using a commercially viable vaccine approach. These results support further development of a DNA vaccine for protection against HIV.

scholarly journals Role of Structural and Non-Structural Proteins and Therapeutic Targets of SARS-CoV-2 for COVID-19

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 821
Author(s):  
Rohitash Yadav ◽  
Jitendra Kumar Chaudhary ◽  
Neeraj Jain ◽  
Pankaj Kumar Chaudhary ◽  
Supriya Khanra ◽  
...  
Keyword(s):  
Host Cell ◽  
Protein S ◽  
Structural Similarity ◽  
Cell Receptor ◽  
Molecular Assembly ◽  
The Body ◽  
Spike Protein ◽  
Structural Proteins ◽  
Structural Protein ◽  
Novel Coronavirus

Coronavirus belongs to the family of Coronaviridae, comprising single-stranded, positive-sense RNA genome (+ ssRNA) of around 26 to 32 kilobases, and has been known to cause infection to a myriad of mammalian hosts, such as humans, cats, bats, civets, dogs, and camels with varied consequences in terms of death and debilitation. Strikingly, novel coronavirus (2019-nCoV), later renamed as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and found to be the causative agent of coronavirus disease-19 (COVID-19), shows 88% of sequence identity with bat-SL-CoVZC45 and bat-SL-CoVZXC21, 79% with SARS-CoV and 50% with MERS-CoV, respectively. Despite key amino acid residual variability, there is an incredible structural similarity between the receptor binding domain (RBD) of spike protein (S) of SARS-CoV-2 and SARS-CoV. During infection, spike protein of SARS-CoV-2 compared to SARS-CoV displays 10–20 times greater affinity for its cognate host cell receptor, angiotensin-converting enzyme 2 (ACE2), leading proteolytic cleavage of S protein by transmembrane protease serine 2 (TMPRSS2). Following cellular entry, the ORF-1a and ORF-1ab, located downstream to 5′ end of + ssRNA genome, undergo translation, thereby forming two large polyproteins, pp1a and pp1ab. These polyproteins, following protease-induced cleavage and molecular assembly, form functional viral RNA polymerase, also referred to as replicase. Thereafter, uninterrupted orchestrated replication-transcription molecular events lead to the synthesis of multiple nested sets of subgenomic mRNAs (sgRNAs), which are finally translated to several structural and accessory proteins participating in structure formation and various molecular functions of virus, respectively. These multiple structural proteins assemble and encapsulate genomic RNA (gRNA), resulting in numerous viral progenies, which eventually exit the host cell, and spread infection to rest of the body. In this review, we primarily focus on genomic organization, structural and non-structural protein components, and potential prospective molecular targets for development of therapeutic drugs, convalescent plasm therapy, and a myriad of potential vaccines to tackle SARS-CoV-2 infection.

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