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1.
Int J Mol Sci ; 23(9)2022 Apr 28.
Article in English | MEDLINE | ID: covidwho-1820291

ABSTRACT

During the sustained COVID-19 pandemic, global mass vaccination to achieve herd immunity can prevent further viral spread and mutation. A protein subunit vaccine that is safe, effective, stable, has few storage restrictions, and involves a liable manufacturing process would be advantageous to distribute around the world. Here, we designed and produced a recombinant spike (S)-Trimer that is maintained in a prefusion state and exhibits a high ACE2 binding affinity. Rodents received different doses of S-Trimer (0.5, 5, or 20 µg) antigen formulated with aluminum hydroxide (Alum) or an emulsion-type adjuvant (SWE), or no adjuvant. After two vaccinations, the antibody response, T-cell responses, and number of follicular helper T-cells (Tfh) or germinal center (GC) B cells were assessed in mice; the protective efficacy was evaluated on a Syrian hamster infection model. The mouse studies demonstrated that adjuvating the S-Trimer with SWE induced a potent humoral immune response and Th1-biased cellular immune responses (in low dose) that were superior to those induced by Alum. In the Syrian hamster studies, when S-Trimer was adjuvanted with SWE, higher levels of neutralizing antibodies were induced against live SARS-CoV-2 from the original lineage and against the emergence of variants (Beta or Delta) with a slightly decreased potency. In addition, the SWE adjuvant demonstrated a dose-sparing effect; thus, a lower dose of S-Trimer as an antigen (0.5 µg) can induce comparable antisera and provide complete protection from viral infection. These data support the utility of SWE as an adjuvant to enhance the immunogenicity of the S-Trimer vaccine, which is feasible for further clinical testing.


Subject(s)
COVID-19 Vaccines , COVID-19 , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Th1 Cells , Adjuvants, Immunologic/pharmacology , Adjuvants, Pharmaceutic , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/pharmacology , Cricetinae , Emulsions , Humans , Mice , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Th1 Cells/immunology
2.
Immunohorizons ; 6(4): 275-282, 2022 Apr 27.
Article in English | MEDLINE | ID: covidwho-1818325

ABSTRACT

Putative subcomponent vaccines of severe acute respiratory syndrome coronavirus spike protein and ARNAX (TLR3-specific adjuvant for priming dendritic cells) were examined and compared with spike protein + Alum in a mouse BALB/c model. Survival, body weight, virus-neutralizing Ab titer in the blood, and viral titer in the lung were evaluated for prognosis markers. The infiltration degrees of eosinophils in the lung were histopathologically monitored at 10 d postinfection. The results were: (1) adjuvant was essential in vaccines to achieve a complete recovery from infection, (2) ARNAX displayed optimal body weight recovery compared with Alum, (3) ARNAX was optimal for the amelioration of eosinophilic pneumonia, and (4) the eosinophil infiltration score was not associated with the neutralizing Ab titer in the blood or viral titer in the lung. Although the pathological link between the TLR3 vaccine and lung eosinophil infiltration remains unclear, severe acute respiratory syndrome-mediated eosinophilic pneumonia can be blocked by the prior induction of dendritic cell priming by ARNAX.


Subject(s)
Pulmonary Eosinophilia , SARS Virus , Viral Vaccines , Adjuvants, Immunologic/pharmacology , Animals , Body Weight , Dendritic Cells , Disease Models, Animal , Mice , Pulmonary Eosinophilia/prevention & control , Toll-Like Receptor 3 , Viral Vaccines/pharmacology
3.
J Microbiol ; 60(5): 550-559, 2022 May.
Article in English | MEDLINE | ID: covidwho-1797492

ABSTRACT

Adjuvants are substances added to vaccines to enhance antigen-specific immune responses or to protect antigens from rapid elimination. As pattern recognition receptors, Toll-like receptors 7 (TLR7) and 8 (TLR8) activate the innate immune system by sensing endosomal single-stranded RNA of RNA viruses. Here, we investigated if a 2,4-diaminoquinazoline-based TLR7/8 agonist, (S)-3-((2-amino-8-fluoroquinazolin-4-yl)amino)hexan-1-ol (named compound 31), could be used as an adjuvant to enhance the serological and mucosal immunity of an inactivated influenza A virus vaccine. The compound induced the production of proinflammatory cytokines in macrophages. In a dose-response analysis, intranasal administration of 1 µg compound 31 together with an inactivated vaccine (0.5 µg) to mice not only enhanced virus-specific IgG and IgA production but also neutralized influenza A virus with statistical significance. Notably, in a virus-challenge model, the combination of the vaccine and compound 31 alleviated viral infection-mediated loss of body weight and increased survival rates by 40% compared with vaccine only-treated mice. We suggest that compound 31 is a promising lead compound for developing mucosal vaccine adjuvants to protect against respiratory RNA viruses such as influenza viruses and potentially coronaviruses.


Subject(s)
Influenza A virus , Influenza Vaccines , Influenza, Human , Orthomyxoviridae Infections , Adjuvants, Immunologic/pharmacology , Administration, Intranasal , Animals , Antibodies, Viral , Humans , Immunity, Mucosal , Mice , Mice, Inbred BALB C , Quinazolines , Toll-Like Receptor 7
4.
Front Immunol ; 13: 833418, 2022.
Article in English | MEDLINE | ID: covidwho-1771038

ABSTRACT

As TLR2 agonists, several lipopeptides had been proved to be candidate vaccine adjuvants. In our previous study, lipopeptides mimicking N-terminal structures of the bacterial lipoproteins were also able to promote antigen-specific immune response. However, the structure-activity relationship of lipopeptides as TLR2 agonists is still unclear. Here, 23 synthetic lipopeptides with the same lipid moiety but different peptide sequences were synthesized, and their TLR2 activities in vitro and mucosal adjuvant effects to OVA were evaluated. LP1-14, LP1-30, LP1-34 and LP2-2 exhibited significantly lower cytotoxicity and stronger TLR2 activity compared with Pam2CSK4, the latter being one of the most potent TLR2 agonists. LP1-34 and LP2-2 assisted OVA to induce more profound specific IgG in sera or sIgA in BALF than Pam2CSK4. Furthermore, the possibility of LP1-34, LP2-2 and Pam2CSK4 as the mucosal adjuvant for the SARS-CoV-2 recombinant RBD (rRBD) was investigated. Intranasally immunized with rRBD plus either the novel lipopeptide or Pam2CSK4 significantly increased the levels of specific serum and respiratory mucosal IgG and IgA, while rRBD alone failed to induce specific immune response due to its low immunogenicity. The novel lipopeptides, especially LP2-2, significantly increased levels of rRBD-induced SARS-CoV-2 neutralizing antibody in sera, BALF and nasal wash. Finally, Support vector machine (SVM) results suggested that charged residues in lipopeptides might be beneficial to the agonist activity, while lipophilic residues might adversely affect the agonistic activity. Figuring out the relationship between peptide sequence in the lipopeptide and its TLR2 activity may lay the foundation for the rational design of novel lipopeptide adjuvant for COVID-19 vaccine.


Subject(s)
COVID-19 , Lipopeptides , Adjuvants, Immunologic/pharmacology , Adjuvants, Pharmaceutic , COVID-19 Vaccines , Humans , Immunity , Immunoglobulin G , Lipopeptides/pharmacology , SARS-CoV-2 , Toll-Like Receptor 2
5.
Chem Commun (Camb) ; 58(24): 3925-3928, 2022 Mar 22.
Article in English | MEDLINE | ID: covidwho-1730326

ABSTRACT

Adjuvants are important components in vaccines to increase the immunogenicity of proteins and induce optimal immunity. In this study, we designed a novel ternary adjuvant system Alum + c-GAMP + poly(I:C) with STING agonist 3,3'-c-GAMP (c-GAMP) and TLR3 agonist poly(I:C) co-adsorbed on the conventional adjuvant aluminum gel (Alum), and further constructed an S1 protein vaccine. Two doses of vaccination with the ternary adjuvant vaccine were sufficient to induce a balanced Th1/Th2 immune response and robust humoral and cellular immunity. Additionally, the ternary adjuvant group had effective neutralizing activity against live virus SARS-CoV-2 and pseudovirus of all variants of concern (alpha, beta, gamma, delta and omicron). These results indicate that the ternary adjuvants have a significant synergistic effect and can rapidly trigger potent immune responses; the combination of the ternary adjuvant system with S1 protein is a promising COVID-19 vaccine candidate.


Subject(s)
COVID-19 , SARS-CoV-2 , Adjuvants, Immunologic/pharmacology , Alum Compounds , Aluminum , Animals , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines/pharmacology , Humans , Immunity, Cellular , Mice , Mice, Inbred BALB C , Poly I
6.
Cell ; 185(4): 614-629.e21, 2022 02 17.
Article in English | MEDLINE | ID: covidwho-1676664

ABSTRACT

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.


Subject(s)
Adjuvants, Immunologic/pharmacology , Antigens, Viral/immunology , Candida albicans/chemistry , Mannans/immunology , Aluminum Hydroxide/chemistry , Animals , Antibodies, Neutralizing/immunology , Antibody Specificity/immunology , B-Lymphocytes/immunology , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Chlorocebus aethiops , Epitopes/immunology , Immunity, Innate , Immunization , Inflammation/pathology , Interferons/metabolism , Lectins, C-Type/metabolism , Ligands , Lung/immunology , Lung/pathology , Lung/virology , Lymph Nodes/immunology , Lymph Nodes/metabolism , Macrophages/metabolism , Mice, Inbred C57BL , Paranasal Sinuses/metabolism , Protein Subunits/metabolism , Sialic Acid Binding Ig-like Lectin 1/metabolism , Solubility , Spike Glycoprotein, Coronavirus/metabolism , T-Lymphocytes/immunology , Transcription Factor RelB/metabolism , Vero Cells , beta-Glucans/metabolism
7.
Lancet Infect Dis ; 21(10): 1383-1394, 2021 10.
Article in English | MEDLINE | ID: covidwho-1621119

ABSTRACT

BACKGROUND: Given the scale of the ongoing COVID-19 pandemic, the development of vaccines based on different platforms is essential, particularly in light of emerging viral variants, the absence of information on vaccine-induced immune durability, and potential paediatric use. We aimed to assess the safety and immunogenicity of an MF59-adjuvanted subunit vaccine for COVID-19 based on recombinant SARS-CoV-2 spike glycoprotein stabilised in a pre-fusion conformation by a novel molecular clamp (spike glycoprotein-clamp [sclamp]). METHODS: We did a phase 1, double-blind, placebo-controlled, block-randomised trial of the sclamp subunit vaccine in a single clinical trial site in Brisbane, QLD, Australia. Healthy adults (aged ≥18 to ≤55 years) who had tested negative for SARS-CoV-2, reported no close contact with anyone with active or previous SARS-CoV-2 infection, and tested negative for pre-existing SARS-CoV-2 immunity were included. Participants were randomly assigned to one of five treatment groups and received two doses via intramuscular injection 28 days apart of either placebo, sclamp vaccine at 5 µg, 15 µg, or 45 µg, or one dose of sclamp vaccine at 45 µg followed by placebo. Participants and study personnel, except the dose administration personnel, were masked to treatment. The primary safety endpoints included solicited local and systemic adverse events in the 7 days after each dose and unsolicited adverse events up to 12 months after dosing. Here, data are reported up until day 57. Primary immunogenicity endpoints were antigen-specific IgG ELISA and SARS-CoV-2 microneutralisation assays assessed at 28 days after each dose. The study is ongoing and registered with ClinicalTrials.gov, NCT04495933. FINDINGS: Between June 23, 2020, and Aug 17, 2020, of 314 healthy volunteers screened, 120 were randomly assigned (n=24 per group), and 114 (95%) completed the study up to day 57 (mean age 32·5 years [SD 10·4], 65 [54%] male, 55 [46%] female). Severe solicited reactions were infrequent and occurred at similar rates in participants receiving placebo (two [8%] of 24) and the SARS-CoV-2 sclamp vaccine at any dose (three [3%] of 96). Both solicited reactions and unsolicited adverse events occurred at a similar frequency in participants receiving placebo and the SARS-CoV-2 sclamp vaccine. Solicited reactions occurred in 19 (79%) of 24 participants receiving placebo and 86 (90%) of 96 receiving the SARS-CoV-2 sclamp vaccine at any dose. Unsolicited adverse events occurred in seven (29%) of 24 participants receiving placebo and 35 (36%) of 96 participants receiving the SARS-CoV-2 sclamp vaccine at any dose. Vaccination with SARS-CoV-2 sclamp elicited a similar antigen-specific response irrespective of dose: 4 weeks after the initial dose (day 29) with 5 µg dose (geometric mean titre [GMT] 6400, 95% CI 3683-11 122), with 15 µg dose (7492, 4959-11 319), and the two 45 µg dose cohorts (8770, 5526-13 920 in the two-dose 45 µg cohort; 8793, 5570-13 881 in the single-dose 45 µg cohort); 4 weeks after the second dose (day 57) with two 5 µg doses (102 400, 64 857-161 676), with two 15 µg doses (74 725, 51 300-108 847), with two 45 µg doses (79 586, 55 430-114 268), only a single 45 µg dose (4795, 2858-8043). At day 57, 67 (99%) of 68 participants who received two doses of sclamp vaccine at any concentration produced a neutralising immune response, compared with six (25%) of 24 who received a single 45 µg dose and none of 22 who received placebo. Participants receiving two doses of sclamp vaccine elicited similar neutralisation titres, irrespective of dose: two 5 µg doses (GMT 228, 95% CI 146-356), two 15 µg doses (230, 170-312), and two 45 µg doses (239, 187-307). INTERPRETATION: This first-in-human trial shows that a subunit vaccine comprising mammalian cell culture-derived, MF59-adjuvanted, molecular clamp-stabilised recombinant spike protein elicits strong immune responses with a promising safety profile. However, the glycoprotein 41 peptide present in the clamp created HIV diagnostic assay interference, a possible barrier to widespread use highlighting the criticality of potential non-spike directed immunogenicity during vaccine development. Studies are ongoing with alternative molecular clamp trimerisation domains to ameliorate this response. FUNDING: Coalition for Epidemic Preparedness Innovations, National Health and Medical Research Council, Queensland Government, and further philanthropic sources listed in the acknowledgments.


Subject(s)
Adjuvants, Immunologic/pharmacology , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Spike Glycoprotein, Coronavirus/immunology , Squalene/immunology , Adult , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Australia , Female , Healthy Volunteers , Humans , Male , Pandemics/prevention & control , Polysorbates , Vaccination/adverse effects , Young Adult
8.
Sci Immunol ; 6(66): eabf1152, 2021 Dec 03.
Article in English | MEDLINE | ID: covidwho-1583226

ABSTRACT

Saponins are potent and safe vaccine adjuvants, but their mechanisms of action remain incompletely understood. Here, we explored the properties of several saponin formulations, including immune-stimulatory complexes (ISCOMs) formed by the self-assembly of saponin and phospholipids in the absence or presence of the Toll-like receptor 4 agonist monophosphoryl lipid A (MPLA). We found that MPLA self-assembles with saponins to form particles physically resembling ISCOMs, which we termed saponin/MPLA nanoparticles (SMNP). Saponin-containing adjuvants exhibited distinctive mechanisms of action, altering lymph flow in a mast cell­dependent manner and promoting antigen entry into draining lymph nodes. SMNP was particularly effective, exhibiting even greater potency than the compositionally related adjuvant AS01B in mice, and primed robust germinal center B cell, TFH, and HIV tier 2 neutralizing antibodies in nonhuman primates. Together, these findings shed new light on mechanisms by which saponin adjuvants act to promote the immune response and suggest that SMNP may be a promising adjuvant in the setting of HIV, SARS-CoV-2, and other pathogens.


Subject(s)
Adaptive Immunity/drug effects , Adjuvants, Immunologic/pharmacology , Lymph/drug effects , Saponins/pharmacology , Toll-Like Receptors/agonists , Animals , B-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/immunology , Female , Lymph/physiology , Macaca mulatta , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Nanoparticles , Rats , Rats, Wistar
9.
Front Immunol ; 12: 743890, 2021.
Article in English | MEDLINE | ID: covidwho-1581344

ABSTRACT

Background: Both anti-viral and anti-inflammatory bronchial effects are warranted to treat viral infections in asthma. We sought to investigate if imiquimod, a TLR7 agonist, exhibits such dual actions in ex vivo cultured human bronchial epithelial cells (HBECs), targets for SARS-CoV-2 infectivity. Objective: To investigate bronchial epithelial effects of imiquimod of potential importance for anti-viral treatment in asthmatic patients. Methods: Effects of imiquimod alone were examined in HBECs from healthy (N=4) and asthmatic (N=18) donors. Mimicking SARS-CoV-2 infection, HBECs were stimulated with poly(I:C), a dsRNA analogue, or SARS-CoV-2 spike-protein 1 (SP1; receptor binding) with and without imiquimod treatment. Expression of SARS-CoV-2 receptor (ACE2), pro-inflammatory and anti-viral cytokines were analyzed by RT-qPCR, multiplex ELISA, western blot, and Nanostring and proteomic analyses. Results: Imiquimod reduced ACE2 expression at baseline and after poly(I:C) stimulation. Imiquimod also reduced poly(I:C)-induced pro-inflammatory cytokines including IL-1ß, IL-6, IL-8, and IL-33. Furthermore, imiquimod increased IFN-ß expression, an effect potentiated in presence of poly(I:C) or SP1. Multiplex mRNA analysis verified enrichment in type-I IFN signaling concomitant with suppression of cytokine signaling pathways induced by imiquimod in presence of poly(I:C). Exploratory proteomic analyses revealed potentially protective effects of imiquimod on infections. Conclusion: Imiquimod triggers viral resistance mechanisms in HBECs by decreasing ACE2 and increasing IFN-ß expression. Additionally, imiquimod improves viral infection tolerance by reducing viral stimulus-induced epithelial cytokines involved in severe COVID-19 infection. Our imiquimod data highlight feasibility of producing pluripotent drugs potentially suited for anti-viral treatment in asthmatic subjects.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Asthma , COVID-19 , Imiquimod/pharmacology , Interferon-beta/drug effects , Respiratory Mucosa/drug effects , Adjuvants, Immunologic/pharmacology , Adult , Aged , Bronchi/drug effects , Bronchi/immunology , Bronchi/virology , Cells, Cultured , Female , Humans , Interferon-beta/immunology , Male , Middle Aged , Respiratory Mucosa/metabolism , Respiratory Mucosa/virology , SARS-CoV-2
10.
Carbohydr Polym ; 285: 118971, 2022 Jun 01.
Article in English | MEDLINE | ID: covidwho-1549670

ABSTRACT

Ligusticum chuanxiong, the dried rhizome of Ligusticum chuanxiong Hort, has been widely applied in traditional Chinese medicine for treating plague, and it has appeared frequently in the prescriptions against COVID-19 lately. Ligusticum chuanxiong polysaccharide (LCPs) is one of the effective substances, which has various activities, such as, anti-oxidation, promoting immunity, anti-tumor, and anti-bacteria. The purified fractions of LCPs are considered to be pectic polysaccharides, which are mainly composed of GalA, Gal, Ara and Rha, and are generally linked by α-1,4-d-GalpA, α-1,2-l-Rhap, α-1,5-l-Araf, ß-1,3-d-Galp and ß-1,4-d-Galp, etc. The pectic polysaccharide shows an anti-infective inflammatory activity, which is related to antiviral infection of Ligusticum chuanxiong. In this article, the isolation, purification, structural features, and biological activities of LCPs in recent years are reviewed, and the potential of LCPs against viral infection as well as questions that need future research are discussed.


Subject(s)
COVID-19/drug therapy , Ligusticum/chemistry , Polysaccharides/chemistry , Polysaccharides/pharmacology , Adjuvants, Immunologic/pharmacology , Adjuvants, Immunologic/therapeutic use , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Antioxidants/pharmacology , Antioxidants/therapeutic use , Antiviral Agents/pharmacology , Antiviral Agents/therapeutic use , COVID-19/virology , Carbohydrate Conformation , Carbohydrate Sequence , Drugs, Chinese Herbal , Humans , Polysaccharides/isolation & purification , SARS-CoV-2/drug effects , SARS-CoV-2/isolation & purification
11.
Int J Biol Macromol ; 193(Pt B): 1885-1897, 2021 Dec 15.
Article in English | MEDLINE | ID: covidwho-1509845

ABSTRACT

The spike (S) protein is a leading vaccine candidate against SARS-CoV-2 infection. The S1 domain of S protein, which contains a critical receptor-binding domain (RBD) antigen, potentially induces protective immunoreactivities against SARS-CoV-2. In this study, we presented preclinical evaluations of a novel insect cell-derived SARS-CoV-2 recombinant S1 (rS1) protein as a potent COVID-19 vaccine candidate. The native antigenicity of rS1 was characterized by enzyme-linked immunosorbent assay with a neutralizing monoclonal antibody targeting the RBD antigen. To improve its immunogenicity, rS1-adjuvanted with fucoidan/trimethylchitosan nanoparticles (FUC-TMC NPs) and cytosine-phosphate-guanosine-oligodeoxynucleotides (CpG-ODNs) were investigated using a mouse model. The S1-specific immunoglobulin G (IgG) titers, FluoroSpot assay, pseudovirus- and prototype SARS-CoV-2-based neutralization assays were assessed. The results showed that the rS1/CpG/ FUC-TMC NPs (rS1/CpG/NPs) formulation induced a broad-spectrum IgG response with potent, long-lasting, and cross-protective neutralizing activity against the emerging SARS-CoV-2 variant of concern, along with a Th1-biased cellular response. Thus, the rS1/CpG/NPs formulation presents a promising vaccination approach against COVID-19.


Subject(s)
Adjuvants, Immunologic , Antibodies, Viral/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19 Vaccines , Immunogenicity, Vaccine , Nanoparticles , Oligodeoxyribonucleotides , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus , Th1 Cells/immunology , Adjuvants, Immunologic/chemistry , Adjuvants, Immunologic/pharmacology , Animals , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/pharmacology , Mice , Mice, Inbred BALB C , Nanoparticles/chemistry , Nanoparticles/therapeutic use , Oligodeoxyribonucleotides/chemistry , Oligodeoxyribonucleotides/pharmacology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/pharmacology
12.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Article in English | MEDLINE | ID: covidwho-1493337

ABSTRACT

The COVID-19 pandemic highlights the importance of efficient and safe vaccine development. Vaccine adjuvants are essential to boost and tailor the immune response to the corresponding pathogen. To allow for an educated selection, we assessed the effect of different adjuvants on human monocyte-derived dendritic cells (DCs) and their ability to polarize innate and adaptive immune responses. In contrast to commonly used adjuvants, such as aluminum hydroxide, Toll-like receptor (TLR) agonists induced robust phenotypic and functional DC maturation. In a DC-lymphocyte coculture system, we investigated the ensuing immune reactions. While monophosphoryl lipid A synthetic, a TLR4 ligand, induced checkpoint inhibitors indicative for immune exhaustion, the TLR7/8 agonist Resiquimod (R848) induced prominent type-1 interferon and interleukin 6 responses and robust CTL, B-cell, and NK-cell proliferation, which is particularly suited for antiviral immune responses. The recently licensed COVID-19 vaccines, BNT162b and mRNA-1273, are both based on single-stranded RNA. Indeed, we could confirm that the cytokine profile induced by lipid-complexed RNA was almost identical to the pattern induced by R848. Although this awaits further investigation, our results suggest that their efficacy involves the highly efficient antiviral response pattern stimulated by the RNAs' TLR7/8 activation.


Subject(s)
Adjuvants, Immunologic/pharmacology , COVID-19/immunology , Dendritic Cells/immunology , Immunity, Cellular/drug effects , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Adolescent , Adult , Aged , Female , Humans , Imidazoles/pharmacology , Lipid A/analogs & derivatives , Lipid A/pharmacology , Male , Middle Aged , Toll-Like Receptors/immunology
13.
Int J Mol Sci ; 22(21)2021 Oct 28.
Article in English | MEDLINE | ID: covidwho-1488614

ABSTRACT

Human Ezrin Peptides (HEPs) are inhibitors of expression of IL-6 and other inflammatory cytokines, amplifiers of adaptive B cell and T cell immunity and enhancers of tissue repair. The mutation stable C-terminus of HIV gp120, mimics 69% of the "Hep-receptor", a zipped α-helical structure in the middle of the α domain of human ezrin protein. Synthetic peptides homologous to the Hep-receptor of ezrin of five to fourteen amino acids, activate anti-viral immunity against a wide range of viruses (HIV, HCV, herpes, HPV, influenza and other human respiratory viruses). Human Ezrin Peptide One (HEP1) TEKKRRETVEREKE (brand name Gepon, registered for human use in Russia from 2001) is a successful treatment for opportunistic infections in HIV-infected patients. That treats HEP1and prevents mucosal candidiasis, herpes zoster outbreaks and infection-induced chronic diarrhea. There are clinical publications in Russian on the successful treatments of chronic recurrent vaginal candidiasis, acute and chronic enterocolitis and dysbacteriosis, which are accompanied by normalization of the mucosal microbiome, and the decline or disappearance of inflammation. HEP1 is also an effective treatment and prevention for recurrent inflammation and ulceration in the stomach, duodenum and colon. HEP1 and RepG3 GEKKRRETVEREGG (a derivative of HEP1) have been used successfully as an inhaled spray peptide solution to treat a small number of human volunteers with mild-to-moderate COVID, resulting from SARS-CoV-2 infection, based on earlier successes in treating acute viral respiratory disease with inflammatory complications. Ezrin peptides seem to correct a dysregulation of innate immune responses to SARS-CoV-2. They are also adjuvants of B cell adaptive immunity and increase antibody titres, resulting in protection from lethal virus infection of mice. In a clinical study in Moscow, orally administered HEP1 was shown to enhance antibody-titres produced in response to hepatitis-B vaccination. These very preliminary but promising results with ezrin peptide treatment of COVID must be replicated in large-scale randomised placebo controlled clinical studies, to be verified.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Cytoskeletal Proteins/pharmacology , Cytoskeletal Proteins/therapeutic use , Adaptive Immunity/drug effects , Adjuvants, Immunologic/pharmacology , Animals , Antiviral Agents/therapeutic use , HIV Infections/drug therapy , Humans , Mice , Respiratory Tract Infections/drug therapy , Virus Diseases/drug therapy
14.
Front Immunol ; 12: 729189, 2021.
Article in English | MEDLINE | ID: covidwho-1450809

ABSTRACT

Several SARS-CoV-2 vaccines have received EUAs, but many issues remain unresolved, including duration of conferred immunity and breadth of cross-protection. Adjuvants that enhance and shape adaptive immune responses that confer broad protection against SARS-CoV-2 variants will be pivotal for long-term protection as drift variants continue to emerge. We developed an intranasal, rationally designed adjuvant integrating a nanoemulsion (NE) that activates TLRs and NLRP3 with an RNA agonist of RIG-I (IVT DI). The combination adjuvant with spike protein antigen elicited robust responses to SARS-CoV-2 in mice, with markedly enhanced TH1-biased cellular responses and high virus-neutralizing antibody titers towards both homologous SARS-CoV-2 and a variant harboring the N501Y mutation shared by B1.1.7, B.1.351 and P.1 variants. Furthermore, passive transfer of vaccination-induced antibodies protected naive mice against heterologous viral challenge. NE/IVT DI enables mucosal vaccination, and has the potential to improve the immune profile of a variety of SARS-CoV-2 vaccine candidates to provide effective cross-protection against future drift variants.


Subject(s)
Adjuvants, Immunologic/pharmacology , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Vaccines, Synthetic/immunology , Adaptive Immunity/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Chlorocebus aethiops , Cross Protection/immunology , DEAD Box Protein 58 , HEK293 Cells , Humans , Immunity, Humoral/immunology , Immunization, Passive , Mice , Mice, Inbred C57BL , Receptors, Immunologic/agonists , Recombinant Proteins/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Vero Cells
15.
Dermatology ; 237(6): 847-856, 2021.
Article in English | MEDLINE | ID: covidwho-1398749

ABSTRACT

BACKGROUND: The innate immune system is recognized as an essential aspect of COVID-19 pathogenesis. Toll-like receptors (TLRs) are important in inducing antiviral response, triggering downstream production of interferons (IFNs). Certain loss-of-function variants in TLR7 are associated with increased COVID-19 disease severity, and imiquimod (ImiQ) is known to have immunomodulating effects as an agonist of TLR7. Given that topical imiquimod (topImiQ) is indicated for various dermatologic conditions, it is necessary for dermatologists to understand the interplay between innate immunity mechanisms and the potential role of ImiQ in COVID-19, with a particular focus on TLR7. SUMMARY: Our objective was to survey recent peer-reviewed scientific literature in the PubMed database, examine relevant evidence, and elucidate the relationships between IFNs, TLR7, the innate immune system, and topImiQ in the context of COVID-19. Despite limited studies on this topic, current evidence supports the critical role of TLRs in mounting a strong immune response against COVID-19. Of particular interest to dermatologists, topImiQ can result in systemic upregulation of the immune system via activation of TLR7. Key Message: Given the role of TLR7 in the systemic activation of the immune system, ImiQ, as a ligand of the TLR7 receptor, may have potential therapeutic benefit as a topical immunomodulatory treatment for COVID-19.


Subject(s)
COVID-19/prevention & control , Imiquimod/administration & dosage , Immunity, Innate , Interferons/administration & dosage , SARS-CoV-2 , Toll-Like Receptor 7/metabolism , Up-Regulation/drug effects , Adjuvants, Immunologic/pharmacology , Administration, Topical , Animals , Antiviral Agents/administration & dosage , COVID-19/epidemiology , COVID-19/metabolism , Humans
16.
Proc Natl Acad Sci U S A ; 118(4)2021 01 26.
Article in English | MEDLINE | ID: covidwho-1387607

ABSTRACT

The global incidence of tuberculosis remains unacceptably high, with new preventative strategies needed to reduce the burden of disease. We describe here a method for the generation of synthetic self-adjuvanted protein vaccines and demonstrate application in vaccination against Mycobacterium tuberculosis Two vaccine constructs were designed, consisting of full-length ESAT6 protein fused to the TLR2-targeting adjuvants Pam2Cys-SK4 or Pam3Cys-SK4 These were produced by chemical synthesis using a peptide ligation strategy. The synthetic self-adjuvanting vaccines generated powerful local CD4+ T cell responses against ESAT6 and provided significant protection in the lungs from virulent M. tuberculosis aerosol challenge when administered to the pulmonary mucosa of mice. The flexible synthetic platform we describe, which allows incorporation of adjuvants to multiantigenic vaccines, represents a general approach that can be applied to rapidly assess vaccination strategies in preclinical models for a range of diseases, including against novel pandemic pathogens such as SARS-CoV-2.


Subject(s)
Mycobacterium tuberculosis/immunology , Tuberculosis Vaccines/pharmacology , Tuberculosis/immunology , Tuberculosis/prevention & control , Vaccines, Conjugate/pharmacology , Adjuvants, Immunologic/pharmacology , Animals , Antigens, Bacterial/immunology , BCG Vaccine/immunology , BCG Vaccine/pharmacology , Bacterial Proteins , CD4-Positive T-Lymphocytes/immunology , COVID-19/prevention & control , Disease Models, Animal , Female , Mice , Mice, Inbred C57BL , SARS-CoV-2/immunology , Toll-Like Receptor 2/immunology , Tuberculosis Vaccines/immunology , Vaccines, Conjugate/immunology , Vaccines, Synthetic/immunology , Vaccines, Synthetic/pharmacology
17.
Front Immunol ; 11: 559382, 2020.
Article in English | MEDLINE | ID: covidwho-1389163

ABSTRACT

Eliciting durable and protective T cell-mediated immunity in the respiratory mucosa remains a significant challenge. Polylactic-co-glycolic acid (PLGA)-based cationic pathogen-like particles (PLPs) loaded with TLR agonists mimic biophysical properties of microbes and hence, simulate pathogen-pattern recognition receptor interactions to safely and effectively stimulate innate immune responses. We generated micro particle PLPs loaded with TLR4 (glucopyranosyl lipid adjuvant, GLA) or TLR9 (CpG) agonists, and formulated them with and without a mucosal delivery enhancing carbomer-based nanoemulsion adjuvant (ADJ). These adjuvants delivered intranasally to mice elicited high numbers of influenza nucleoprotein (NP)-specific CD8+ and CD4+ effector and tissue-resident memory T cells (TRMs) in lungs and airways. PLPs delivering TLR4 versus TLR9 agonists drove phenotypically and functionally distinct populations of effector and memory T cells. While PLPs loaded with CpG or GLA provided immunity, combining the adjuvanticity of PLP-GLA and ADJ markedly enhanced the development of airway and lung TRMs and CD4 and CD8 T cell-dependent immunity to influenza virus. Further, balanced CD8 (Tc1/Tc17) and CD4 (Th1/Th17) recall responses were linked to effective influenza virus control. These studies provide mechanistic insights into vaccine-induced pulmonary T cell immunity and pave the way for the development of a universal influenza and SARS-CoV-2 vaccines.


Subject(s)
Adjuvants, Immunologic/pharmacology , Immunity, Cellular/immunology , Influenza A virus/immunology , Intraepithelial Lymphocytes/immunology , Animals , Cell Line , Dogs , Immunity, Innate/immunology , Immunologic Memory/immunology , Lung/immunology , Lung/virology , Madin Darby Canine Kidney Cells , Mice , Mice, Inbred C57BL , Orthomyxoviridae Infections/immunology , Polylactic Acid-Polyglycolic Acid Copolymer/immunology , Toll-Like Receptor 4/immunology
18.
Proc Natl Acad Sci U S A ; 118(34)2021 08 24.
Article in English | MEDLINE | ID: covidwho-1345645

ABSTRACT

Alum, used as an adjuvant in injected vaccines, promotes T helper 2 (Th2) and serum antibody (Ab) responses. However, it fails to induce secretory immunoglobulin (Ig) A (SIgA) in mucosal tissues and is poor in inducing Th1 and cell-mediated immunity. Alum stimulates interleukin 1 (IL-1) and the recruitment of myeloid cells, including neutrophils. We investigated whether neutrophil elastase regulates the adjuvanticity of alum, and whether a strategy targeting neutrophil elastase could improve responses to injected vaccines. Mice coadministered a pharmacological inhibitor of elastase, or lacking elastase, developed high-affinity serum IgG and IgA antibodies after immunization with alum-adsorbed protein vaccines, including the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). These mice also developed broader antigen-specific CD4+ T cell responses, including high Th1 and T follicular helper (Tfh) responses. Interestingly, in the absence of elastase activity, mucosal SIgA responses were induced after systemic immunization with alum as adjuvant. Importantly, lack or suppression of elastase activity enhanced the magnitude of anti-SARS-CoV-2 spike subunit 1 (S1) antibodies, and these antibodies reacted with the same epitopes of spike 1 protein as sera from COVID-19 patients. Therefore, suppression of neutrophil elastase could represent an attractive strategy for improving the efficacy of alum-based injected vaccines for the induction of broad immunity, including mucosal immunity.


Subject(s)
Adjuvants, Immunologic/pharmacology , Alum Compounds/pharmacology , COVID-19/immunology , COVID-19/therapy , Enzyme Inhibitors/pharmacology , Leukocyte Elastase/antagonists & inhibitors , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antibody Formation/drug effects , COVID-19/drug therapy , COVID-19/metabolism , HEK293 Cells , Humans , Immunity, Innate/drug effects , Immunity, Innate/immunology , Immunity, Mucosal/drug effects , Immunity, Mucosal/immunology , Immunoglobulin A/immunology , Leukocyte Elastase/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/immunology , Swine , Th1 Cells/immunology
20.
Int J Mol Sci ; 22(13)2021 Jun 26.
Article in English | MEDLINE | ID: covidwho-1304664

ABSTRACT

Hepatitis C virus (HCV) is one of the main triggers of chronic liver disease. Despite tremendous progress in the HCV field, there is still no vaccine against this virus. Potential vaccines can be based on its recombinant proteins. To increase the humoral and, especially, cellular immune response to them, more effective adjuvants are needed. Here, we evaluated a panel of compounds as potential adjuvants using the HCV NS5B protein as an immunogen. These compounds included inhibitors of polyamine biosynthesis and urea cycle, the mTOR pathway, antioxidants, and cellular receptors. A pronounced stimulation of cell proliferation and interferon-γ (IFN-γ) secretion in response to concanavalin A was shown for antioxidant N-acetylcysteine (NAC), polyamine biosynthesis inhibitor 2-difluoromethylornithine (DFMO), and TLR9 agonist CpG ODN 1826 (CpG). Their usage during the immunization of mice with the recombinant NS5B protein significantly increased antibody titers, enhanced lymphocyte proliferation and IFN-γ production. NAC and CpG decreased relative Treg numbers; CpG increased the number of myeloid-derived suppressor cells (MDSCs), whereas neither NAC nor DFMO affected MDSC counts. NAC and DFMO suppressed NO and interleukin 10 (IL-10) production by splenocytes, while DFMO increased the levels of IL-12. This is the first evidence of immunomodulatory activity of NAC and DFMO during prophylactic immunization against infectious diseases.


Subject(s)
Acetylcysteine/pharmacology , Adjuvants, Immunologic/pharmacology , Eflornithine/pharmacology , Hepatitis C/immunology , Immunity, Active/drug effects , Viral Nonstructural Proteins/immunology , Animals , Cell Proliferation , Cells, Cultured , Female , Immunogenicity, Vaccine/drug effects , Interferon-gamma/metabolism , Interleukin-10/metabolism , Interleukin-12/metabolism , Mice , Mice, Inbred DBA , Myeloid-Derived Suppressor Cells/drug effects , Myeloid-Derived Suppressor Cells/immunology , Nitric Oxide/metabolism , Oligodeoxyribonucleotides/pharmacology , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology , Viral Hepatitis Vaccines/immunology
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