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1.
Viruses ; 14(11)2022 Nov 04.
Article in English | MEDLINE | ID: covidwho-2143699

ABSTRACT

Small molecular nucleic acid drugs produce antiviral effects by activating pattern recognition receptors (PRRs). In this study, a small molecular nucleotide containing 5'triphosphoric acid (5'PPP) and possessing a double-stranded structure was designed and named nCoV-L. nCoV-L was found to specifically activate RIG-I, induce interferon responses, and inhibit duplication of four RNA viruses (Human enterovirus 71, Human poliovirus 1, Human coxsackievirus B5 and Influenza A virus) in cells. In vivo, nCoV-L quickly induced interferon responses and protected BALB/c suckling mice from a lethal dose of the enterovirus 71. Additionally, prophylactic administration of nCoV-L was found to reduce mouse death and relieve morbidity symptoms in a K18-hACE2 mouse lethal model of SARS-CoV-2. In summary, these findings indicate that nCoV-L activates RIG-I and quickly induces effective antiviral signals. Thus, it has potential as a broad-spectrum antiviral drug.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Mice , Animals , DEAD-box RNA Helicases/genetics , RNA, Viral/genetics , Cell Line , DEAD Box Protein 58 , Mice, Inbred BALB C , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , Interferons
2.
Front Immunol ; 13: 1023255, 2022.
Article in English | MEDLINE | ID: covidwho-2142030

ABSTRACT

SARS-CoV-2 vaccines currently in use have contributed to controlling the COVID-19 pandemic. Notwithstanding, the high mutation rate, fundamentally in the spike glycoprotein (S), is causing the emergence of new variants. Solely utilizing this antigen is a drawback that may reduce the efficacy of these vaccines. Herein we present a DNA vaccine candidate that contains the genes encoding the S and the nucleocapsid (N) proteins implemented into the non-replicative mammalian expression plasmid vector, pPAL. This plasmid lacks antibiotic resistance genes and contains an alternative selectable marker for production. The S gene sequence was modified to avoid furin cleavage (Sfs). Potent humoral and cellular immune responses were observed in C57BL/6J mice vaccinated with pPAL-Sfs + pPAL-N following a prime/boost regimen by the intramuscular route applying in vivo electroporation. The immunogen fully protected K18-hACE2 mice against a lethal dose (105 PFU) of SARS-CoV-2. Viral replication was completely controlled in the lungs, brain, and heart of vaccinated mice. Therefore, pPAL-Sfs + pPAL-N is a promising DNA vaccine candidate for protection from COVID-19.


Subject(s)
COVID-19 , Vaccines, DNA , Viral Vaccines , Mice , Animals , Humans , SARS-CoV-2 , COVID-19 Vaccines , Pandemics , Mice, Inbred BALB C , Mice, Inbred C57BL , COVID-19/prevention & control , Anti-Bacterial Agents , Mammals
3.
J Microbiol Biotechnol ; 32(10): 1335-1343, 2022 Oct 28.
Article in English | MEDLINE | ID: covidwho-2115579

ABSTRACT

COVID-19 is an emerging disease that poses a severe threat to global public health. As such, there is an urgent demand for vaccines against SARS-CoV-2, the virus that causes COVID-19. Here, we describe a virus-like nanoparticle candidate vaccine against SARS-CoV-2 produced by an E. coli expression system. The fusion protein of a truncated ORF2-encoded protein of aa 439~608 (p170) from hepatitis E virus CCJD-517 and the receptor-binding domain of the spike protein from SARS-CoV-2 were expressed, purified and characterized. The antigenicity and immunogenicity of p170-RBD were evaluated in vitro and in Kunming mice. Our investigation revealed that p170-RBD self-assembled into approximately 24 nm virus-like particles, which could bind to serum from vaccinated people (p < 0.001) and receptors on cells. Immunization with p170-RBD induced the titer of IgG antibody vaccine increased from 14 days post-immunization and was significantly enhanced after a booster immunization at 28 dpi, ultimately reaching a peak level on 42 dpi with a titer of 4.97 log10. Pseudovirus neutralization tests showed that the candidate vaccine induced a strong neutralizing antibody response in mice. In this research, we demonstrated that p170-RBD possesses strong antigenicity and immunogenicity and could be a potential candidate for use in future SARS-CoV-2 vaccine development.


Subject(s)
COVID-19 , Hepatitis E virus , Viral Vaccines , Animals , Humans , Mice , Antibodies, Neutralizing , Antibodies, Viral , Capsid Proteins/genetics , COVID-19/prevention & control , COVID-19 Vaccines/genetics , Escherichia coli , Mice, Inbred BALB C , Recombinant Proteins/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Viral Vaccines/genetics
4.
Int J Mol Sci ; 23(22)2022 Nov 08.
Article in English | MEDLINE | ID: covidwho-2110127

ABSTRACT

The pandemic of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed great threat to the world in many aspects. There is an urgent requirement for an effective preventive vaccine. The receptor binding domain (RBD), located on the spike (S) gene, is responsible for binding to the angiotensin-converting enzyme 2 (ACE2) receptor of host cells. The RBD protein is an effective and safe antigen candidate. The six-helix bundle (6HB) "molecular clamp" is a novel thermally-stable trimerization domain derived from a human immunodeficiency virus (HIV) gp41 protein segment. We selected the baculovirus system to fuse and express the RBD protein and 6HB for imitating the natural trimeric structure of RBD, named RBD-6HB. Recombinant RBD-6HB was successfully obtained from the cell culture supernatant and purified to high homogeneity. The purity of the final protein preparation was more than 97%. The results showed that the protein was identified as a homogeneous polymer. Further studies showed that the RBD-6HB protein combined with AL/CpG adjuvant could stimulate animals to produce sustained high-level antibodies and establish an effective protective barrier to protect mice from challenges. Our findings highlight the importance of trimerized SARS-CoV-2 S protein RBD in designing SARS-CoV-2 vaccines and provide a rationale for developing a protective vaccine through the induction of antibodies against the RBD domain.


Subject(s)
COVID-19 , Viral Vaccines , Humans , Mice , Animals , COVID-19 Vaccines , Mice, Inbred BALB C , SARS-CoV-2 , COVID-19/prevention & control , Antibodies
5.
Pharmacol Res ; 186: 106546, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-2095888

ABSTRACT

Mucosal vaccination is regarded as a promising alternative to classical, intramuscular vaccine delivery. However, only a limited number of vaccines have been licensed for mucosal administration in humans. Here we propose Leishmania tarentolae, a protozoan parasite, as a potential antigen vehicle for mucosal vaccination, for administration via the rectal or oral routes. To test this hypothesis, we exploited L. tarentolae for the production and delivery of SARS-CoV-2 antigens. Two antigens were assayed in BALB/c mice: Lt-spike, a L. tarentolae clone engineered for the surface expression of the SARS-CoV-2 spike protein; RBD-SD1, a purified portion of the spike protein, produced by another engineered clone of the protozoon. Immune response parameters were then determined at different time points. Both antigens, administered either separately or in combination (Lt-spike + RBD-SD1, hereafter LeCoVax-2), determined significant IgG seroconversion and production of neutralizing antibodies after subcutaneous administration, but only in the presence of adjuvants. After rectal administration, the purified RBD-SD1 antigen did not induce any detectable immune response, in comparison with the intense response observed after administration of LeCoVax-2 or Lt-spike alone. In rectal administration, LeCoVax-2 was also effective when administered without adjuvant. Our results show that L. tarentolae is an efficient and safe scaffold for production and delivery of viral antigens, to be used as vaccines. In addition, rectal vaccination experiments prove that L. tarentolae is suitable as a vaccine vehicle and adjuvant for enteral vaccination. Finally, the combined preparation LeCoVax-2 can be considered as a promising candidate vaccine against SARS-CoV-2, worthy of further investigation.


Subject(s)
COVID-19 , Parasites , Mice , Animals , Humans , COVID-19 Vaccines , COVID-19/prevention & control , Administration, Rectal , SARS-CoV-2 , Vaccination/methods , Mice, Inbred BALB C , Adjuvants, Immunologic , Immunoglobulin G
6.
Emerg Microbes Infect ; 11(1): 2724-2734, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-2087655

ABSTRACT

The development of safe and effective vaccines to respond to COVID-19 pandemic/endemic remains a priority. We developed a novel subunit protein-peptide COVID-19 vaccine candidate (UB-612) composed of: (i) receptor binding domain of SARS-CoV-2 spike protein fused to a modified single-chain human IgG1 Fc; (ii) five synthetic peptides incorporating conserved helper and cytotoxic T lymphocyte (Th/CTL) epitopes derived from SARS-CoV-2 structural proteins (three from S2 subunit, one from membrane and one from nucleocapsid), and one universal Th peptide; (iii) aluminum phosphate as adjuvant. The immunogenicity and protective immunity induced by UB-612 vaccine were evaluated in four animal models: Sprague-Dawley rats, AAV-hACE2 transduced BALB/c mice, rhesus and cynomolgus macaques. UB-612 vaccine induced high levels of neutralizing antibody and T-cell responses, in all animals. The immune sera from vaccinated animals neutralized the SARS-CoV-2 original wild-type strains and multiple variants of concern, including Delta and Omicron. The vaccination significantly reduced viral loads, lung pathology scores, and disease progression after intranasal and intratracheal challenge with SARS-CoV-2 in mice, rhesus and cynomolgus macaques. UB-612 has been tested in primary regimens in Phase 1 and Phase 2 clinical studies and is currently being evaluated in a global pivotal Phase 3 clinical study as a single dose heterologous booster.


Subject(s)
COVID-19 , Viral Vaccines , Rats , Mice , Humans , Animals , SARS-CoV-2 , COVID-19 Vaccines , Broadly Neutralizing Antibodies , Pandemics/prevention & control , COVID-19/prevention & control , Rats, Sprague-Dawley , Spike Glycoprotein, Coronavirus , Antibodies, Neutralizing , Vaccines, Subunit/genetics , Mice, Inbred BALB C , Macaca mulatta , Antibodies, Viral
7.
Nat Commun ; 13(1): 6309, 2022 Oct 23.
Article in English | MEDLINE | ID: covidwho-2087203

ABSTRACT

Coronavirus vaccines that are highly effective against current and anticipated SARS-CoV-2 variants are needed to control COVID-19. We previously reported a receptor-binding domain (RBD)-sortase A-conjugated ferritin nanoparticle (scNP) vaccine that induced neutralizing antibodies against SARS-CoV-2 and pre-emergent sarbecoviruses and protected non-human primates (NHPs) from SARS-CoV-2 WA-1 infection. Here, we find the RBD-scNP induced neutralizing antibodies in NHPs against pseudoviruses of SARS-CoV and SARS-CoV-2 variants including 614G, Beta, Delta, Omicron BA.1, BA.2, BA.2.12.1, and BA.4/BA.5, and a designed variant with escape mutations, PMS20. Adjuvant studies demonstrate variant neutralization titers are highest with 3M-052-aqueous formulation (AF). Immunization twice with RBD-scNPs protect NHPs from SARS-CoV-2 WA-1, Beta, and Delta variant challenge, and protect mice from challenges of SARS-CoV-2 Beta variant and two other heterologous sarbecoviruses. These results demonstrate the ability of RBD-scNPs to induce broad neutralization of SARS-CoV-2 variants and to protect animals from multiple different SARS-related viruses. Such a vaccine could provide broad immunity to SARS-CoV-2 variants.


Subject(s)
COVID-19 , Nanoparticles , SARS Virus , Viral Vaccines , Mice , Animals , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus , Antibodies, Viral , Mice, Inbred BALB C , COVID-19/prevention & control , Antibodies, Neutralizing/chemistry , Ferritins
8.
Front Immunol ; 13: 1004045, 2022.
Article in English | MEDLINE | ID: covidwho-2080154

ABSTRACT

Haemodialysis patients respond poorly to vaccination and continue to be at-risk for severe COVID-19. Therefore, dialysis patients were among the first for which a fourth COVID-19 vaccination was recommended. However, targeted information on how to best maintain immune protection after SARS-CoV-2 vaccinations in at-risk groups for severe COVID-19 remains limited. We provide, to the best of our knowledge, for the first time longitudinal vaccination response data in dialysis patients and controls after a triple BNT162b2 vaccination and in the latter after a subsequent fourth full-dose of mRNA-1273. We analysed systemic and mucosal humoral IgG responses against the receptor-binding domain (RBD) and ACE2-binding inhibition towards variants of concern including Omicron and Delta with multiplex-based immunoassays. In addition, we assessed Spike S1-specific T-cell responses by interferon γ release assay. After triple BNT162b2 vaccination, anti-RBD B.1 IgG and ACE2 binding inhibition reached peak levels in dialysis patients, but remained inferior compared to controls. Whilst we detected B.1-specific ACE2 binding inhibition in 84% of dialysis patients after three BNT162b2 doses, binding inhibition towards the Omicron variant was only detectable in 38% of samples and declining to 16% before the fourth vaccination. By using mRNA-1273 as fourth dose, humoral immunity against all SARS-CoV-2 variants tested was strongly augmented with 80% of dialysis patients having Omicron-specific ACE2 binding inhibition. Modest declines in T-cell responses in dialysis patients and controls after the second vaccination were restored by the third BNT162b2 dose and significantly increased by the fourth vaccination. Our data support current advice for a four-dose COVID-19 immunisation scheme for at-risk individuals such as haemodialysis patients. We conclude that administration of a fourth full-dose of mRNA-1273 as part of a mixed mRNA vaccination scheme to boost immunity and to prevent severe COVID-19 could also be beneficial in other immune impaired individuals. Additionally, strategic application of such mixed vaccine regimens may be an immediate response against SARS-CoV-2 variants with increased immune evasion potential.


Subject(s)
COVID-19 , Viral Vaccines , Mice , Animals , Humans , Immunity, Humoral , SARS-CoV-2 , 2019-nCoV Vaccine mRNA-1273 , BNT162 Vaccine , COVID-19/prevention & control , Angiotensin-Converting Enzyme 2 , COVID-19 Vaccines , Mice, Inbred BALB C , Vaccination , Immunoglobulin G , Renal Dialysis , RNA, Messenger
9.
Cell Mol Immunol ; 19(11): 1302-1310, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-2062196

ABSTRACT

Mutations in SARS-CoV-2 variants of concern (VOCs) have enhanced transmissibility and immune evasion with respect to current vaccines and neutralizing antibodies (NAbs). How naturally occurring spike mutations affect the infectivity and antigenicity of VOCs remains to be investigated. The entry efficiency of individual spike mutations was determined in vitro using pseudotyped viruses. BALB/c mice were immunized with 2-dose DNA vaccines encoding B.1.1.7, B.1.351, B.1.1.529  and their single mutations. Cellular and humoral immune responses were then compared to determine the impact of individual mutations on immunogenicity. In the B.1.1.7 lineage, Del69-70 and Del 144 in NTD, A570D and P681H in SD1 and S982A and D1118H in S2 significantly increased viral entry, whereas T716I resulted in a decrease. In the B.1.351 lineage, L18F and Del 242-244 in the NTD, K417N in the RBD and A701V in S2 also increased viral entry. S982A weakened the generation of binding antibodies. All sera showed reduced cross-neutralization activity against B.1.351, B.1.617.2 (Delta) and B.1.1.529 (Omicron BA.1). S982A, L18F, and Del 242-244 hindered the induction of cross-NAbs, whereas Del 69-70, Del144, R246I, and K417N showed the opposite effects. B.1.351 elicited adequate broad cross-NAbs against both B.1.351 and B.1.617.2. All immunogens tested, however, showed low neutralization against circulating B.1.1.529. In addition, T-cell responses were unlikely affected by mutations tested in the spike. We conclude that individual spike mutations influence viral infectivity and vaccine immunogenicity. Designing VOC-targeted vaccines is likely necessary to overcome immune evasion from current vaccines and neutralizing antibodies.


Subject(s)
COVID-19 , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Animals , Humans , Mice , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/immunology , COVID-19/virology , Mice, Inbred BALB C , Mutation , Neutralization Tests , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
10.
Sheng Wu Gong Cheng Xue Bao ; 38(9): 3353-3362, 2022 Sep 25.
Article in Chinese | MEDLINE | ID: covidwho-2056455

ABSTRACT

A fusion protein containing a tetanus toxin peptide, a tuftsin peptide and a SARS-CoV-2S protein receptor-binding domain (RBD) was prepared to investigate the effect of intramolecular adjuvant on humoral and cellular immunity of RBD protein. The tetanus toxin peptide, tuftsin peptide and S protein RBD region were connected by a flexible polypeptide, and a recombinant vector was constructed after codon optimization. The recombinant S-TT-tuftsin protein was prepared by prokaryotic expression and purification. BALB/c mice were immunized after mixed with aluminum adjuvant, and the humoral and cellular immune effects were evaluated. The recombinant S-TT-tuftsin protein was expressed as an inclusion body, and was purified by ion exchange chromatography and renaturated by gradient dialysis. The renaturated protein was identified by Dot blotting and reacted with serum of descendants immunized with SARS-CoV-2 subunit vaccine. The results showed that the antibody level reached a plateau after 35 days of immunization, and the serum antibody ELISA titer of mice immunized with recombinant protein containing intramolecular adjuvant was up to 1:66 240, which was significantly higher than that of mice immunized with S-RBD protein (P < 0.05). At the same time, the recombinant protein containing intramolecular adjuvant stimulated mice to produce a stronger lymphocyte proliferation ability. The stimulation index was 4.71±0.15, which was significantly different from that of the S-RBD protein (1.83±0.09) (P < 0.000 1). Intramolecular adjuvant tetanus toxin peptide and tuftsin peptide significantly enhanced the humoral and cellular immune effect of the SARS-CoV-2 S protein RBD domain, which provideda theoretical basis for the development of subunit vaccines for SARS-CoV-2 and other viruses.


Subject(s)
COVID-19 , Tuftsin , Viral Vaccines , Adjuvants, Immunologic , Aluminum , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/genetics , Humans , Mice , Mice, Inbred BALB C , Recombinant Proteins/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Tetanus Toxin , Vaccines, Subunit
11.
BMC Complement Med Ther ; 22(1): 242, 2022 Sep 17.
Article in English | MEDLINE | ID: covidwho-2043124

ABSTRACT

BACKGROUND: Ecklonia cava is an edible marine brown alga harvested from the ocean that is widely consumed in Asian countries as a health-promoting medicinal food The objective of the present study is to evaluate the anti-asthma mechanism of a new functional food produced by bioprocessing edible algae Ecklonia cava and shiitake Lentinula edodes mushroom mycelia and isolated fractions. METHODS: We used as series of methods, including high performance liquid chromatography, gas chromatography, cell assays, and an in vivo mouse assay to evaluate the asthma-inhibitory effect of Ecklonia cava bioprocessed (fermented) with Lentinula edodes shiitake mushroom mycelium and its isolated fractions in mast cells and in orally fed mice. RESULTS: The treatments inhibited the degranulation of RBL-2H3 cells and immunoglobulin E (IgE) production, suggesting anti-asthma effects in vitro. The in vitro anti-asthma effects in cells were confirmed in mice following the induction of asthma by alumina and chicken egg ovalbumin (OVA). Oral administration of the bioprocessed Ecklonia cava and purified fractions suppressed the induction of asthma and was accompanied by the inhibition of inflammation- and immune-related substances, including eotaxin; thymic stromal lymphopoietin (TSLP); OVA-specific IgE; leukotriene C4 (LTC4); prostaglandin D2 (PGD2); and vascular cell adhesion molecule-1 (VCAM-1) in bronchoalveolar lavage fluid (BALF) and other fluids and organs. Th2 cytokines were reduced and Th1 cytokines were restored in serum, suggesting the asthma-induced inhibitory effect is regulated by the balance of the Th1/Th2 immune response. Serum levels of IL-10, a regulatory T cell (Treg) cytokine, were increased, further favoring reduced inflammation. Histology of lung tissues revealed that the treatment also reversed the thickening of the airway wall and the contraction and infiltration of bronchial and blood vessels and perialveolar inflammatory cells. The bioprocessed Ecklonia cava/mushroom mycelia new functional food showed the highest inhibition as compared with commercial algae and the fractions isolated from the bioprocessed product. CONCLUSIONS: The in vitro cell and in vivo mouse assays demonstrate the potential value of the new bioprocessed formulation as an anti-inflammatory and anti-allergic combination of natural compounds against allergic asthma and might also ameliorate allergic manifestations of foods, drugs, and viral infections.


Subject(s)
Agaricales , Anti-Allergic Agents , Anti-Asthmatic Agents , Asthma , Phaeophyta , Shiitake Mushrooms , Aluminum Oxide/adverse effects , Animals , Anti-Allergic Agents/adverse effects , Anti-Asthmatic Agents/pharmacology , Anti-Inflammatory Agents/pharmacology , Asthma/drug therapy , Cytokines/metabolism , Immunoglobulin E , Inflammation/drug therapy , Interleukin-10 , Leukotriene C4/adverse effects , Mice , Mice, Inbred BALB C , Mycelium , Ovalbumin/adverse effects , Phaeophyta/metabolism , Prostaglandin D2/adverse effects , Shiitake Mushrooms/metabolism , Vascular Cell Adhesion Molecule-1/adverse effects
12.
Int J Biol Macromol ; 222(Pt A): 661-670, 2022 Dec 01.
Article in English | MEDLINE | ID: covidwho-2041799

ABSTRACT

SARS-CoV-2 is a particularly transmissible virus that causes a severe respiratory disease known as COVID-19. Safe and effective vaccines are urgently needed to combat the COVID-19 pandemic. The receptor-binding domain (RBD) of SARS-CoV-2 spike protein elicits most neutralizing antibodies during viral infection and is an ideal antigen for vaccine development. In particular, RBD expressed by E. coli is amenable to low cost and high-yield manufacturability. The adjuvant is necessitated to improve the immunogenicity of RBD. IC28, a TLR5-dependent adjuvant, is a peptide from bacterial flagellin. Mannan is a ligand of TLR-4 or TLR-2 and a polysaccharide adjuvant. Here, IC28 and mannan were both covalently conjugated with RBD from E. coli. The conjugate (RBD-IC28-M) elicited high RBD-specific IgG titers, and a neutralization antibody titer of 201.4. It induced high levels of Th1-type cytokines (IFN-γ) and Th2-type cytokines (IL-5 and IL-10), along with high antigenicity and no apparent toxicity to the organs. The mouse sera of the RBD-IC28-M group competitively interfered with the interaction of RBD and ACE2. Thus, conjugation with IC28 and mannan additively enhanced the humoral and cellular immunity. Our study was expected to provide the feasibility to develop an affordable, easily scalable, effective vaccine SARS-CoV-2 vaccine.


Subject(s)
COVID-19 , Viral Vaccines , Humans , Mice , Animals , COVID-19 Vaccines , SARS-CoV-2 , Mannans , Pandemics/prevention & control , Escherichia coli , COVID-19/prevention & control , Mice, Inbred BALB C , Antibodies, Neutralizing , Peptides , Cytokines , Antibodies, Viral
13.
Nat Commun ; 13(1): 5459, 2022 09 17.
Article in English | MEDLINE | ID: covidwho-2036822

ABSTRACT

The recently emerged Omicron (B.1.1.529) variant has rapidly surpassed Delta to become the predominant circulating SARS-CoV-2 variant, given the higher transmissibility rate and immune escape ability, resulting in breakthrough infections in vaccinated individuals. A new generation of SARS-CoV-2 vaccines targeting the Omicron variant are urgently needed. Here, we developed a subunit vaccine named RBD-HR/trimer by directly linking the sequence of RBD derived from the Delta variant (containing L452R and T478K) and HR1 and HR2 in SARS-CoV-2 S2 subunit in a tandem manner, which can self-assemble into a trimer. In multiple animal models, vaccination of RBD-HR/trimer formulated with MF59-like oil-in-water adjuvant elicited sustained humoral immune response with high levels of broad-spectrum neutralizing antibodies against Omicron variants, also inducing a strong T cell immune response in vivo. In addition, our RBD-HR/trimer vaccine showed a strong boosting effect against Omicron variants after two doses of mRNA vaccines, featuring its capacity to be used in a prime-boost regimen. In mice and non-human primates, RBD-HR/trimer vaccination could confer a complete protection against live virus challenge of Omicron and Delta variants. The results qualified RBD-HR/trimer vaccine as a promising next-generation vaccine candidate for prevention of SARS-CoV-2, which deserved further evaluation in clinical trials.


Subject(s)
COVID-19 , Viral Vaccines , Animals , Antibodies, Neutralizing , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Mice , Mice, Inbred BALB C , Protein Subunits , SARS-CoV-2 , Vaccines, Subunit , Water
14.
Nanomedicine ; 46: 102604, 2022 11.
Article in English | MEDLINE | ID: covidwho-2031589

ABSTRACT

The current vaccine development strategies for the COVID-19 pandemic utilize whole inactive or attenuated viruses, virus-like particles, recombinant proteins, and antigen-coding DNA and mRNA with various delivery strategies. While highly effective, these vaccine development strategies are time-consuming and often do not provide reliable protection for immunocompromised individuals, young children, and pregnant women. Here, we propose a novel modular vaccine platform to address these shortcomings using chemically synthesized peptides identified based on the validated bioinformatic data about the target. The vaccine is based on the rational design of an immunogen containing two defined B-cell epitopes from the spike glycoprotein of SARS-CoV-2 and the universal T-helper epitope PADRE. The epitopes were conjugated to short DNA probes and combined with a complementary scaffold strand, resulting in sequence-specific self-assembly. The immunogens were then formulated by conjugation to gold nanoparticles by three methods or by co-crystallization with epsilon inulin. BALB/C mice were immunized with each formulation, and the IgG immune responses and virus neutralizing titers were compared. The results demonstrate that this assembly is immunogenic and generates neutralizing antibodies against wildtype SARS-CoV-2 and the Delta variant.


Subject(s)
COVID-19 , Metal Nanoparticles , Pregnancy Complications, Infectious , Viral Vaccines , Pregnancy , Mice , Animals , Female , Humans , SARS-CoV-2 , COVID-19 Vaccines , Spike Glycoprotein, Coronavirus/chemistry , Pandemics/prevention & control , COVID-19/prevention & control , Gold , Mice, Inbred BALB C , Antibodies, Neutralizing , Epitopes, B-Lymphocyte/chemistry , Antibodies, Viral
15.
Front Cell Infect Microbiol ; 12: 967493, 2022.
Article in English | MEDLINE | ID: covidwho-2029957

ABSTRACT

Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), has posed a constant threat to human beings and the world economy for more than two years. Vaccination is the first choice to control and prevent the pandemic. However, an effective SARS-CoV-2 vaccine against the virus infection is still needed. This study designed and prepared four kinds of virus-like particles (VLPs) using an insect expression system. Two constructs encoded wild-type SARS-CoV-2 spike (S) fused with or without H5N1 matrix 1 (M1) (S and SM). The other two constructs contained a codon-optimized spike gene and/or M1 gene (mS and mSM) based on protein expression, stability, and ADE avoidance. The results showed that the VLP-based vaccine could induce high SARS-CoV-2 specific antibodies in mice, including specific IgG, IgG1, and IgG2a. Moreover, the mSM group has the most robust ability to stimulate humoral immunity and cellular immunity than the other VLPs, suggesting the mSM is the best immunogen. Further studies showed that the mSM combined with Al/CpG adjuvant could stimulate animals to produce sustained high-level antibodies and establish an effective protective barrier to protect mice from challenges with mouse-adapted strain. The vaccine based on mSM and Al/CpG adjuvant is a promising candidate vaccine to prevent the COVID-19 pandemic.


Subject(s)
COVID-19 , Influenza A Virus, H5N1 Subtype , Viral Vaccines , Adjuvants, Immunologic/pharmacology , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/genetics , Humans , Immunoglobulin G , Mice , Mice, Inbred BALB C , Pandemics/prevention & control , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
16.
Biomed Res Int ; 2022: 3510423, 2022.
Article in English | MEDLINE | ID: covidwho-2020494

ABSTRACT

Purpose: Aurantiamide acetate (AA) is a dipeptide derivative with complex pharmacological activities and remarkable effects on preventing and treating various diseases. In the current study, we aimed to investigate whether AA can exert protective effects in a mouse model of ALI induced by LPS. Materials and Methods: In this model, mice were given intranasal LPS for 3 days prior to receiving AA (2.5, 5, and 10 mg/kg) via oral gavage. An assessment of histopathological changes was performed by hematoxylin and eosin (HE). Proinflammatory cytokines were detected in bronchoalveolar lavage fluids (BALFs) by enzyme-linked immunosorbent assays (ELISAs). The effects of AA on protein expression of NF-κB and PI3K/AKT signaling pathways were determined by Western blot. In addition, lung wet/dry (W/D) weight ratio, myeloperoxidase (MPO) activity, cell counts, and protein content were also measured. Results: According to results, AA pretreatment significantly reduced lung pathological changes, W/D ratio, MPO activity, and protein content. Additionally, AA resulted in a significant reduction in the number of total cells, neutrophils, and proinflammatory cytokines in the BALF after LPS stimulation. The subsequent study revealed that pretreatment with AA dose dependently suppressed LPS-induced activation of NF-κB as well as PI3K/AKT phosphorylation. Conclusion: The results indicated that the AA had a protective effect on LPS-induced ALI in mice and could be a potential drug for ALI.


Subject(s)
Acute Lung Injury , Pneumonia , Acute Lung Injury/chemically induced , Acute Lung Injury/drug therapy , Acute Lung Injury/metabolism , Animals , Bronchoalveolar Lavage Fluid/chemistry , Cytokines/metabolism , Dipeptides/pharmacology , Lipopolysaccharides/adverse effects , Lung/pathology , Mice , Mice, Inbred BALB C , NF-kappa B/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Pneumonia/pathology , Proto-Oncogene Proteins c-akt/metabolism
17.
Plant Biotechnol J ; 20(12): 2298-2312, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-2019572

ABSTRACT

The ongoing coronavirus disease 2019 (COVID-19) pandemic has spurred rapid development of vaccines as part of the public health response. However, the general strategy used to construct recombinant trimeric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) proteins in mammalian cells is not completely adaptive to molecular farming. Therefore, we generated several constructs of recombinant S proteins for high expression in Nicotiana benthamiana. Intramuscular injection of N. benthamiana-expressed Sct vaccine (NSct Vac) into Balb/c mice elicited both humoral and cellular immune responses, and booster doses increased neutralizing antibody titres. In human angiotensin-converting enzyme knock-in mice, two doses of NSct Vac induced anti-S and neutralizing antibodies, which cross-neutralized Alpha, Beta, Delta and Omicron variants. Survival rates after lethal challenge with SARS-CoV-2 were up to 80%, without significant body weight loss, and viral titres in lung tissue fell rapidly, with no infectious virus detectable at 7-day post-infection. Thus, plant-derived NSct Vac could be a candidate COVID-19 vaccine.


Subject(s)
COVID-19 Vaccines , COVID-19 , Mice , Animals , Humans , Tobacco/genetics , SARS-CoV-2 , COVID-19/prevention & control , Adjuvants, Immunologic , Mice, Inbred BALB C , Antibodies, Neutralizing , Immunity , Mammals
18.
Vaccine ; 40(37): 5494-5503, 2022 09 02.
Article in English | MEDLINE | ID: covidwho-2016161

ABSTRACT

In recent years, several advances have been observed in vaccinology especially for neglected tropical diseases (NTDs). One of the tools employed is epitope prediction by immunoinformatic approaches that reduce the time and cost to develop a vaccine. In this scenario, immunoinformatics is being more often used to develop vaccines for NTDs, in particular visceral leishmaniasis (VL) which is proven not to have an effective vaccine yet. Based on that, in a previous study, two predicted T-cell multi-epitope chimera vaccines were experimentally validated in BALB/c mice to evaluate the immunogenicity, central and effector memory and protection against VL. Considering the results obtained in the mouse model, we assessed the immune response of these chimeras inMesocricetus auratushamster, which displays, experimentally, similar pathological status to human and dog VL disease. Our findings indicate that both chimeras lead to a dominant Th1 response profile, inducing a strong cellular response by increasing the production of IFN-γ and TNF-α cytokines associated with a decrease in IL-10. Also, the chimeras reduced the spleen parasite load and the weight a correlation between protector immunological mechanisms and consistent reduction of the parasitic load was observed. Our results demonstrate that both chimeras were immunogenic and corroborate with findings in the mouse model. Therefore, we reinforce the use of the hamster as a pre-clinical model in vaccination trials for canine and human VL and the importance of immunoinformatic to identify epitopes to design vaccines for this important neglected disease.


Subject(s)
Leishmania infantum , Leishmaniasis Vaccines , Leishmaniasis, Visceral , Th1 Cells , Animals , Cricetinae , Dogs , Humans , Mice , Adjuvants, Immunologic , Antigens, Protozoan , Cytokines , Dog Diseases , Epitopes, T-Lymphocyte , Leishmaniasis, Visceral/prevention & control , Mice, Inbred BALB C , Spleen
19.
Vaccine ; 40(40): 5757-5763, 2022 09 22.
Article in English | MEDLINE | ID: covidwho-2004590

ABSTRACT

Respiratory transmission of SARS-CoV-2 is considered to be the major dissemination route for COVID-19, therefore, mucosal immune responses have great importance in preventing SARS-CoV-2 from infection. In this study, we constructed a recombinant Vaccinia virus (VV) harboring trimeric receptor-binding domain (RBD) of SARS-CoV-2 spike protein (VV-tRBD), and evaluated the immune responses towards RBD following intranasal immunization against mice and rabbits. In BALB/c mice, intranasal immunization with VV-tRBD elicited robust humoral and cellular immune responses, with high-level of both neutralizing IgG and IgA in sera against SARS-CoV-2 psudoviruses, and a number of RBD-specific IFN-γ-secreting lymphocytes. Sera from immunized rabbits also exhibited neutralization effects. Notably, RBD-specific secretory IgA (sIgA) in both nasal washes and bronchoalveolar lavage fluids (BALs) were detectable and showed substantial neutralization activities. Collectively, a recombinant VV expressing trimeric RBD confers robust systemic immune response and mucosal neutralizing antibodies, thus warranting further exploration as a mucosal vaccine.


Subject(s)
COVID-19 , Viral Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , Humans , Immunization , Mice , Mice, Inbred BALB C , Rabbits , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Vaccinia virus/genetics
20.
Nanomedicine ; 45: 102595, 2022 09.
Article in English | MEDLINE | ID: covidwho-2004369

ABSTRACT

The development of safe and effective vaccine formulations against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a hallmark in the history of vaccines. Here we report a COVID-19 subunit vaccine based on a SARS-CoV-2 Spike protein receptor binding domain (RBD) incorporated into nano-multilamellar vesicles (NMV) associated with monophosphoryl lipid A (MPLA). The results based on immunization of C57BL/6 mice demonstrated that recombinant antigen incorporation into NMVs improved antibody and T-cell responses without inducing toxic effects under both in vitro and in vivo conditions. Administration of RBD-NMV-MPLA formulations modulated antigen avidity and IgG subclass responses, whereas MPLA incorporation improved the activation of CD4+/CD8+ T-cell responses. In addition, immunization with the complete vaccine formulation reduced the number of doses required to achieve enhanced serum virus-neutralizing antibody titers. Overall, this study highlights NMV/MPLA technology, displaying the performance improvement of subunit vaccines against SARS-CoV-2, as well as other infectious diseases.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Humans , Immunity , Immunoglobulin G , Lipids , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Spike Glycoprotein, Coronavirus , Vaccines, Subunit
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