scholarly journals Chimeric Fusion (F) and Attachment (G) Glycoprotein Antigen Delivery by mRNA as a Candidate Nipah Vaccine

2021 ◽  
Vol 12 ◽  
Author(s):  
Rebecca J. Loomis ◽  
Anthony T. DiPiazza ◽  
Samantha Falcone ◽  
Tracy J. Ruckwardt ◽  
Kaitlyn M. Morabito ◽  
...  
Keyword(s):  
Nipah Virus ◽  
Neutralizing Antibody ◽  
T Cell Response ◽  
Antigen Delivery ◽  
Design Elements ◽  
C Terminus ◽  
Glycoprotein Antigen ◽  
Pandemic Threat ◽  
Covalently Linked ◽  
Selection Of

Nipah virus (NiV) represents a significant pandemic threat with zoonotic transmission from bats-to-humans with almost annual regional outbreaks characterized by documented human-to-human transmission and high fatality rates. Currently, no vaccine against NiV has been approved. Structure-based design and protein engineering principles were applied to stabilize the fusion (F) protein in its prefusion trimeric conformation (pre-F) to improve expression and increase immunogenicity. We covalently linked the stabilized pre-F through trimerization domains at the C-terminus to three attachment protein (G) monomers, forming a chimeric design. These studies detailed here focus on mRNA delivery of NiV immunogens in mice, assessment of mRNA immunogen-specific design elements and their effects on humoral and cellular immunogenicity. The pre-F/G chimera elicited a strong neutralizing antibody response and a superior NiV-specific Tfh and other effector T cell response compared to G alone across both the mRNA and protein platforms. These findings enabled final candidate selection of pre-F/G Fd for clinical development.

scholarly journals Rapid selection of HIV envelopes that bind to neutralizing antibody B cell lineage members with functional improbable mutations

Cell Reports ◽  
2021 ◽  
Vol 36 (7) ◽  
pp. 109561
Author(s):  
Olivia Swanson ◽  
Brianna Rhodes ◽  
Avivah Wang ◽  
Shi-Mao Xia ◽  
Robert Parks ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Lineage ◽  
Neutralizing Antibody ◽  
Selection Of

Crystal structure of hexanoyl-CoA bound to β-ketoacyl reductase FabG4 of Mycobacterium tuberculosis

2013 ◽  
Vol 450 (1) ◽  
pp. 127-139 ◽  
Author(s):  
Debajyoti Dutta ◽  
Sudipta Bhattacharyya ◽  
Amlan Roychowdhury ◽  
Rupam Biswas ◽  
Amit Kumar Das
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Active Site ◽  
Ternary Complex ◽  
Catalytic Mechanism ◽  
Acyl Carrier Protein ◽  
Structural Data ◽  
Acid Synthesis ◽  
Binary Complex ◽  
C Terminus ◽  
Covalently Linked

FabGs, or β-oxoacyl reductases, are involved in fatty acid synthesis. The reaction entails NADPH/NADH-mediated conversion of β-oxoacyl-ACP (acyl-carrier protein) into β-hydroxyacyl-ACP. HMwFabGs (high-molecular-weight FabG) form a phylogenetically separate group of FabG enzymes. FabG4, an HMwFabG from Mycobacterium tuberculosis, contains two distinct domains, an N-terminal ‘flavodoxintype’ domain and a C-terminal oxoreductase domain. The catalytically active C-terminal domain utilizes NADH to reduce β-oxoacyl-CoA to β-hydroxyacyl-CoA. In the present study the crystal structures of the FabG4–NADH binary complex and the FabG4–NAD+–hexanoyl-CoA ternary complex have been determined to understand the substrate specificity and catalytic mechanism of FabG4. This is the first report to demonstrate how FabG4 interacts with its coenzyme NADH and hexanoyl-CoA that mimics an elongating fattyacyl chain covalently linked with CoA. Structural analysis shows that the binding of hexanoyl-CoA within the active site cavity of FabG significantly differs from that of the C16 fattyacyl substrate bound to mycobacterial FabI [InhA (enoyl-ACP reductase)]. The ternary complex reveals that both loop I and loop II interact with the phosphopantetheine moiety of CoA or ACP to align the covalently linked fattyacyl substrate near the active site. Structural data ACP inhibition studies indicate that FabG4 can accept both CoA- and ACP-based fattyacyl substrates. We have also shown that in the FabG4 dimer Arg146 and Arg445 of one monomer interact with the C-terminus of the second monomer to play pivotal role in substrate association and catalysis.

All Is Right with the World

2015 ◽  
Vol 6 (4) ◽  
pp. 78-94
Author(s):  
Sharath Sasidharan
Keyword(s):  
Cognitive Dissonance ◽  
Important Determinant ◽  
Belief Systems ◽  
Consumer Trust ◽  
Website Design ◽  
Design Elements ◽  
Schema Congruity ◽  
Business To Consumer ◽  
The Impact ◽  
Selection Of

Business-to-Consumer e-commerce vendors view consumer trust as an important determinant of purchasing intent. Based on the cognitive dissonance and schema-congruity theories, this paper examines the impact of schema-congruity between the website design elements of color and typography with the product context in impacting trust. Websites perceived as compatible with subconsciously internalized belief systems and hence deemed schema-congruent by consumers are expected to engender higher levels of trust. A controlled experimental study involving 128 participants spanning eight different schema-congruency conditions was conducted. Results indicated that completely schema-congruent websites engendered higher levels of trust. Partially schema-congruent and schema-incongruent websites registered significantly lower levels of trust due to cognitive dissonance arising out of their incompatibility with consumer belief systems. The judicious selection of color and typography perceived as schema-congruent with the product context can serve to enhance consumer trust in e-commerce websites.

scholarly journals CD8 T Cell Responses to an Immunodominant Epitope within the Nonstructural Protein NS1 Provide Wide Immunoprotection against Bluetongue Virus in IFNAR−/−Mice

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Alejandro Marín-López ◽  
Eva Calvo-Pinilla ◽  
Diego Barriales ◽  
Gema Lorenzo ◽  
Alejandro Brun ◽  
...  
Keyword(s):  
T Cell ◽  
Bluetongue Virus ◽  
Neutralizing Antibodies ◽  
Nonstructural Protein ◽  
T Cell Responses ◽  
Neutralizing Antibody ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
N Terminus

ABSTRACTThe development of vaccines against bluetongue, a prevalent livestock disease, has been focused on surface antigens that induce strong neutralizing antibody responses. Because of their antigenic variability, these vaccines are usually serotype restricted. We now show that a single highly conserved nonstructural protein, NS1, expressed in a modified vaccinia Ankara virus (MVA) vector can provide multiserotype protection in IFNAR−/−129 mice against bluetongue virus (BTV) that is largely dependent on CD8 T cell responses. We found that the protective antigenic capacity of NS1 resides within the N terminus of the protein and is provided in the absence of neutralizing antibodies. The protective CD8 T cell response requires the presence of a specific peptide within the N terminus of NS1, since its deletion ablates the efficacy of the vaccine formulation. These data reveal the importance of the nonstructural protein NS1 in CD8 T cell-mediated protection against multiple BTV serotypes when vectorized as a recombinant MVA vaccine.IMPORTANCEConventional vaccines have controlled or limited BTV expansion in the past, but they cannot address the need for cross-protection among serotypes and do not allow distinguishing between infected and vaccinated animals (DIVA strategy). There is a need to develop universal vaccines that induce effective protection against multiple BTV serotypes. In this work we have shown the importance of the nonstructural protein NS1, conserved among all the BTV serotypes, in CD8 T cell-mediated protection against multiple BTV serotypes when vectorized as a recombinant MVA vaccine.

scholarly journals A Novel Sortase, SrtC2, from Streptococcus pyogenes Anchors a Surface Protein Containing a QVPTGV Motif to the Cell Wall

2004 ◽  
Vol 186 (17) ◽  
pp. 5865-5875 ◽  
Author(s):  
Timothy C. Barnett ◽  
Aman R. Patel ◽  
June R. Scott
Keyword(s):  
Cell Wall ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Surface Protein ◽  
Surface Proteins ◽  
Human Pathogen ◽  
Hydrophobic Region ◽  
C Terminus ◽  
Group A ◽  
Covalently Linked

ABSTRACT The important human pathogen Streptococcus pyogenes (group A streptococcus GAS), requires several surface proteins to interact with its human host. Many of these are covalently linked by a sortase enzyme to the cell wall via a C-terminal LPXTG motif. This motif is followed by a hydrophobic region and charged C terminus, which are thought to retard the protein in the cell membrane to facilitate recognition by the membrane-localized sortase. Previously, we identified two sortase enzymes in GAS. SrtA is found in all GAS strains and anchors most proteins containing LPXTG, while SrtB is present only in some strains and anchors a subset of LPXTG-containing proteins. We now report the presence of a third sortase in most strains of GAS, SrtC. We show that SrtC mediates attachment of a protein with a QVPTGV motif preceding a hydrophobic region and charged tail. We also demonstrate that the QVPTGV sequence is a substrate for anchoring of this protein by SrtC. Furthermore, replacing this motif with LPSTGE, found in the SrtA-anchored M protein of GAS, leads to SrtA-dependent secretion of the protein but does not lead to its anchoring by SrtA. We conclude that srtC encodes a novel sortase that anchors a protein containing a QVPTGV motif to the surface of GAS.

scholarly journals Archaeosome Adjuvant Overcomes Tolerance to Tumor-Associated Melanoma Antigens Inducing Protective CD8+T Cell Responses

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
Lakshmi Krishnan ◽  
Lise Deschatelets ◽  
Felicity C. Stark ◽  
Komal Gurnani ◽  
G. Dennis Sprott
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Regulatory Cells ◽  
T Cell Responses ◽  
T Cell Response ◽  
Antigen Delivery ◽  
Antigenic Peptides ◽  
Cell Responses ◽  
Tumor Protection ◽  
Melanoma Antigens

Vesicles comprised of the ether glycerolipids of the archaeonMethanobrevibacter smithii(archaeosomes) are potent adjuvants for evoking CD8+T cell responses. We therefore explored the ability of archaeosomes to overcome immunologic tolerance to self-antigens. Priming and boosting of mice with archaeosome-antigen evoked comparable CD8+T cell response and tumor protection to an alternate boosting strategy utilizing live bacterial vectors for antigen delivery. Vaccination with melanoma antigenic peptides TRP181-189and Gp10025-33delivered in archaeosomes resulted in IFN-γproducing antigen-specific CD8+T cells with strong cytolytic capability and protection against subcutaneous B16 melanoma. Targeting responses against multiple antigens afforded prolonged median survival against melanoma challenge. Entrapment of multiple peptides within the same vesicle or admixed formulations were both effective at evoking CD8+T cells against each antigen. Melanoma-antigen archaeosome formulations also afforded therapeutic protection against established B16 tumors when combined with depletion of T-regulatory cells. Overall, we demonstrate that archaeosome adjuvants constitute an effective choice for formulating cancer vaccines.

scholarly journals Human Immunodeficiency Virus Type 1 Env Trimer Immunization of Macaques and Impact of Priming with Viral Vector or Stabilized Core Protein

2008 ◽  
Vol 83 (2) ◽  
pp. 540-551 ◽  
Author(s):  
Andreas Mörner ◽  
Iyadh Douagi ◽  
Mattias N. E. Forsell ◽  
Christopher Sundling ◽  
Pia Dosenovic ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Response ◽  
Neutralizing Antibody ◽  
T Cell Response ◽  
The Core ◽  
Core Proteins ◽  
Immunodeficiency Virus ◽  
Stable Core ◽  
Hiv 1

ABSTRACT Currently there is limited information about the quality of immune responses elicited by candidate human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env)-based immunogens in primates. Here we describe a comprehensive analysis of neutralizing antibody and T-cell responses obtained in cynomolgus macaques by three selected immunization regimens. We used the previously described YU2-based gp140 protein trimers administered in an adjuvant, preceded by two distinct priming strategies: either alphavirus replicon particles expressing matched gp140 trimers or gp120 core proteins stabilized in the CD4-bound conformation. The rationale for priming with replicon particles was to evaluate the impact of the expression platform on trimer immunogenicity. The stable core proteins were chosen in an attempt to expand selectively lymphocytes recognizing common determinants between the core and trimers to broaden the immune response. The results presented here demonstrate that the platform by which Env trimers were delivered in the priming (either protein or replicon vector) had little impact on the overall immune response. In contrast, priming with stable core proteins followed by a trimer boost strikingly focused the T-cell response on the core sequences of HIV-1 Env. The specificity of the T-cell response was distinctly different from that of the responses obtained in animals immunized with trimers alone and was shown to be mediated by CD4+ T cells. However, this regimen showed limited or no improvement in the neutralizing antibody responses, suggesting that further immunogen design efforts are required to successfully focus the B-cell response on conserved neutralizing determinants of HIV-1 Env.

scholarly journals Stability and biological activities of heterodimeric and single-chain equine LH/chorionic gonadotropin variants

2008 ◽  
Vol 40 (4) ◽  
pp. 185-198 ◽  
Author(s):  
Sébastien Legardinier ◽  
Jean-Claude Poirier ◽  
Danièle Klett ◽  
Yves Combarnous ◽  
Claire Cahoreau
Keyword(s):  
Thermal Stability ◽  
Chorionic Gonadotropin ◽  
Sf9 Cells ◽  
Β Subunit ◽  
Single Chain ◽  
Α Subunit ◽  
C Terminus ◽  
N Terminus ◽  
Covalently Linked

Recombinant equine LH/chorionic gonadotropin (eLH/CG) was expressed in the baculovirus–Sf9 insect cell system either as a single-chain with the C-terminus of the β-subunit fused to the N-terminus of the α-subunit or as non-covalently linked heterodimers with or without a polyhistidine tag at various locations. All these non-covalently linked eLH/CG variants were secreted as stable heterodimers in the medium of infected Sf9 cells. To assess the influence of the presence and the position of polyhistidine tag on LH bioactivity, we expressed four non-covalently linked tagged heterodimeric eLH/CG variants that were secreted in threefold higher quantities than the single chain. Among them, only two exhibited full in vitro LH bioactivity, relative to untagged heterodimers, namely the one His-tagged at the N-terminus of α-subunit and the other at the C-terminus of the β-subunit both of which are amenable to nickel-affinity purification. Furthermore, single-chain eLH/CG was found to be N- and O-glycosylated but nevertheless less active in in vitro LH bioassays than natural eCG and heterodimeric recombinant eLH/CG. The thermal stability of natural and recombinant hormones was assessed by the initial rates of dissociation from 20 to 90 °C. Heterodimeric eLH/CG from Sf9 cells was found to be as stable as pituitary eLH and serum eCG (T1/2, 74–77 °C). Although Sf9 cells only elaborated short immature-type carbohydrate side chains on glycoproteins, recombinant eLH/CG produced in these cells exhibited stabilities similar to that of pituitary eLH. In conclusion, recombinant heterodimeric eLH/CG exhibits the same thermal stability as natural pituitary LH and its advantages over the single-chain eLH/CG include higher secretion, higher in vitro bioactivity, and reduced potential risk of immunogenicity.

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