scholarly journals Large-scale analysis of B-cell epitopes of envelope: Implications for Zika vaccine and immunotherapeutic development

F1000Research ◽  
2019 ◽  
Vol 7 ◽  
pp. 1624
Author(s):  
Iman Almansour ◽  
Rahaf Alfares ◽  
Halah Aljofi
Keyword(s):  
B Cell ◽  
Zika Virus ◽  
Large Scale ◽  
Human Mabs ◽  
Bioinformatics Analyses ◽  
Multiple Sequence ◽  
B Cell Epitopes ◽  
E Protein ◽  
The Impact

Background:Cases of the re-emergence of Zika virus in 2015 were associated with severe neurologic complications, including Gillien-Barre syndrome in adults and congenital Zika syndrome in newborns. The major structural determinant of immunity to the Zika virus is the E protein. Although B-cell epitopes of Zika E protein were recently identified, data regarding epitope variations among Zika strains in pre-epidemic and epidemic periods are lacking.Methods:Here, we conducted systematic bioinformatics analyses of Zika strains isolated between 1968 and 2017. Multiple sequence alignment of E protein as well as B-cell epitopes annotations were performed. In addition, homology-based approach was utilized to construct three-dimensional structures of monomeric E glycoproteins to annotate epitope variations. Lastly, prediction of ofN-glycosylation patterns and prediction of protein stability upon mutations were also investigated.Results:Our analyses indicates that epitopes recognized by human mAbs ZIKV-117, ZIKV-15, and ZIKV-19 were highly conserved, suggesting as attractive targets for the development of vaccines and immunotherapeutics directed against diverse Zika strains. In addition, the epitope recognized by ZIKV-E-2A10G6 mAb derived from immunized mice was mostly conserved across Zika strains.Conclusions:Our data provide new insights regarding antigenic similarities between Zika strains circulating worldwide. These data are essential for understanding the impact of evolution on antigenic cross-reactivity between Zika lineages and strains. Furtherin-vitroanalyses are needed to determine how mutationsat predefined epitopes could impact the development of vaccines that can effectively neutralize Zika viruses.

scholarly journals Large-scale analysis of B-cell epitopes of envelope: Implications for Zika vaccine and immunotherapeutic development

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1624 ◽  
Author(s):  
Iman Almansour ◽  
Rahaf Alfares ◽  
Halah Aljofi
Keyword(s):  
B Cell ◽  
Zika Virus ◽  
Large Scale ◽  
Human Mabs ◽  
Bioinformatics Analyses ◽  
Multiple Sequence ◽  
B Cell Epitopes ◽  
E Protein ◽  
The Impact

Background:Cases of the re-emergence of Zika virus in 2015 were associated with severe neurologic complications, including Gillien-Barre syndrome in adults and congenital Zika syndrome in newborns. The major structural determinant of immunity to the Zika virus is the E protein. Although B-cell epitopes of Zika E protein were recently identified, data regarding epitope variations among Zika strains in pre-epidemic and epidemic periods are lacking.Methods:Here, we conducted systematic bioinformatics analyses of Zika strains isolated between 1968 and 2017. Multiple sequence alignment of E protein as well as B-cell epitopes annotations were performed. In addition, homology-based approach was utilized to construct three-dimensional structures of monomeric E glycoproteins to annotate epitope variations. Lastly, ofN-glycosylation patterns and prediction of protein stability upon mutations were also investigated.Results:Our analyses indicates that epitopes recognized by human mAbs ZIKV-117, ZIKV-15, and ZIKV-119 were highly conserved, suggesting as attractive targets for the development of vaccines and immunotherapeutics directed against diverse Zika strains. In addition, the epitope recognized by ZIKV-E-2A10G6 mAb derived from immunized mice was highly conserved across Zika strains.Conclusions:Our data provide new insights regarding antigenic similarities between Zika strains circulating worldwide. These data are essential for understanding the impact of evolution on antigenic cross-reactivity between Zika lineages and strains. Furtherin-vitroanalyses are needed to determine how mutations could impact the development of vaccines that can effectively neutralize Zika viruses.

scholarly journals Site-specific N-glycosylation analysis of animal cell culture-derived Zika virus proteins

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander Pralow ◽  
Alexander Nikolay ◽  
Arnaud Leon ◽  
Yvonne Genzel ◽  
Erdmann Rapp ◽  
...  
Keyword(s):  
Zika Virus ◽  
Animal Cell ◽  
Gradient Centrifugation ◽  
Viral Envelope ◽  
Protein Glycosylation ◽  
High Yield ◽  
Structural Protein ◽  
Site Specific ◽  
E Protein ◽  
The Impact

AbstractHere, we present for the first time, a site-specific N-glycosylation analysis of proteins from a Brazilian Zika virus (ZIKV) strain. The virus was propagated with high yield in an embryo-derived stem cell line (EB66, Valneva SE), and concentrated by g-force step-gradient centrifugation. Subsequently, the sample was proteolytically digested with different enzymes, measured via a LC–MS/MS-based workflow, and analyzed in a semi-automated way using the in-house developed glyXtoolMS software. The viral non-structural protein 1 (NS1) was glycosylated exclusively with high-mannose structures on both potential N-glycosylation sites. In case of the viral envelope (E) protein, no specific N-glycans could be identified with this method. Nevertheless, N-glycosylation could be proved by enzymatic de-N-glycosylation with PNGase F, resulting in a strong MS-signal of the former glycopeptide with deamidated asparagine at the potential N-glycosylation site N444. This confirmed that this site of the ZIKV E protein is highly N-glycosylated but with very high micro-heterogeneity. Our study clearly demonstrates the progress made towards site-specific N-glycosylation analysis of viral proteins, i.e. for Brazilian ZIKV. It allows to better characterize viral isolates, and to monitor glycosylation of major antigens. The method established can be applied for detailed studies regarding the impact of protein glycosylation on antigenicity and human pathogenicity of many viruses including influenza virus, HIV and corona virus.

scholarly journals B-Cell Epitope Discovery: The First Protein Flexibility-Based Algorithm – Zika Virus Conserved Epitope Demonstration

2020 ◽  
Author(s):  
Daniel W. Biner ◽  
Jason S. Grosch ◽  
Peter J. Ortoleva
Keyword(s):  
B Cell ◽  
Zika Virus ◽  
Clustering Algorithm ◽  
Cell Epitope ◽  
Protein Flexibility ◽  
Accessible Surface Area ◽  
Solvent Accessible Surface Area ◽  
B Cell Epitopes ◽  
Enveloped Virus ◽  
Epitope Discovery

<p></p><p>Antibody-antigen interaction – at antigenic local environments called B-cell epitopes – is a prominent mechanism for neutralization of infection. Effective mimicry, and display, of B-cell epitopes is key to vaccine design. Here, a physical approach is evaluated for the discovery of epitopes which evolve slowly over closely related pathogens (conserved epitopes). The approach is 1) protein flexibility-based and 2) demonstrated with clinically relevant enveloped viruses, simulated via molecular dynamics. The approach is validated against 1) seven structurally characterized enveloped virus epitopes which evolved the least (out of thirty-eight enveloped virus-antibody structures) and 2) eight preexisting epitope and peptide discovery algorithms. Rationale for a new benchmarking scheme is presented. A data-driven epitope clustering algorithm is introduced. The prediction of eleven Zika virus epitopes (for future exploration on recombinant vaccine technologies) is demonstrated. For the first time, protein flexibility is shown to outperform solvent accessible surface area as an epitope discovery metric.</p><p></p>

scholarly journals Microfluidic deep mutational scanning of the human executioner caspases reveals differences in structure and regulation

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Hridindu Roychowdury ◽  
Philip A. Romero
Keyword(s):  
Large Scale ◽  
Cysteine Proteases ◽  
Amino Acid Substitutions ◽  
Substrate Preferences ◽  
Functional Differences ◽  
Caspase Family ◽  
Executioner Caspases ◽  
The Impact ◽  
Human Caspase

AbstractThe human caspase family comprises 12 cysteine proteases that are centrally involved in cell death and inflammation responses. The members of this family have conserved sequences and structures, highly similar enzymatic activities and substrate preferences, and overlapping physiological roles. In this paper, we present a deep mutational scan of the executioner caspases CASP3 and CASP7 to dissect differences in their structure, function, and regulation. Our approach leverages high-throughput microfluidic screening to analyze hundreds of thousands of caspase variants in tightly controlled in vitro reactions. The resulting data provides a large-scale and unbiased view of the impact of amino acid substitutions on the proteolytic activity of CASP3 and CASP7. We use this data to pinpoint key functional differences between CASP3 and CASP7, including a secondary internal cleavage site, CASP7 Q196 that is not present in CASP3. Our results will open avenues for inquiry in caspase function and regulation that could potentially inform the development of future caspase-specific therapeutics.

Abstract 152: Stat4 Deficiency limits the Development and Progression of Atherosclerosis

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Paresa Taghavie-Moghadam ◽  
Matthew Butcher ◽  
Mark Kaplan ◽  
Jerry Nadler ◽  
Elena Galkina
Keyword(s):  
T Cells ◽  
B Cell ◽  
Plaque Burden ◽  
Chow Diet ◽  
Th1 Cells ◽  
Peripheral Tissues ◽  
The Impact ◽  
Deficient Mice

T helper 1 (Th1) cells constitute the majority of plaque infiltrating IFNγ+ T cells and play a pro-atherogenic role. Th1 cells are induced via IFNγ-dependent activation of T-box expressed in T cells (Tbet) and/or IL-12-dependent activation of signal transducer and activator of transcription 4 (Stat4). While the role of Tbet in atherosclerosis is established, the impact of the IL-12/Stat4-dependent pathway is not well defined. To address the role of Stat4 in atherosclerosis, we bred Stat4-deficient mice with Apolipoprotein E-deficient mice to generate Stat4-/-Apoe-/- mice. Deficiency of Stat4 resulted in approximately a 70% reduction in the plaque burden for 34 week old Stat4-/-Apoe-/- mice fed a chow diet and in 12 week old Stat4-/-Apoe-/- mice fed a western diet there was approximately a 40% reduction in plaque burden, both compared with diet matched Apoe-/- controls females (p<0.001). To assess the effect of Stat4 on Th1 and Treg cell differentiation, we performed an in vitro polarization assay. Deficiency of Stat4 reduced differentiation of IFNγ+ Th1 cells in Th1 conditions, but supported the induction of Tregs in Treg polarizing conditions, confirming the importance of Stat4 in regulating the Th1/Treg balance. In contrast to the in vitro results, we found no difference in the expression of both IFNγ and Foxp3 amongst Stat4-/-Apoe-/- and Apoe-/- lymph nodes and splenic CD4+ T cells; suggesting that additional cytokines in vivo may induce IFNγ+Th1 and inhibit Treg differentiation. Stat4 deficiency also resulted in increased splenic B cell numbers and a slight increase in B1a dependent T15/E06 mRNA expression. Stat4 is a powerful regulator of chemokine expression within peripheral tissues. Adoptively transferred Apoe-/- B cells and CD11b+ cells migrated more efficiently into Stat4-/-Apoe-/- aortas compared to Apoe-/- recipients. However, percentages of macrophages, as determined by CD11b+CD68+ were reduced within the spleens and aortas of Stat4-/-Apoe-/- mice as compared to Apoe-/- controls at steady state conditions. In conclusion, Stat4 deficiency results in reduced atherosclerosis via the modulation of B cell function and aortic leukocyte content.

scholarly journals Exposure to airborne gold nanoparticles: a review of current toxicological data on the respiratory tract

2020 ◽  
Vol 22 (8) ◽  
Author(s):  
Barbara De Berardis ◽  
Magda Marchetti ◽  
Anna Risuglia ◽  
Federica Ietto ◽  
Carla Fanizza ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Human Health ◽  
Large Scale ◽  
Current Knowledge ◽  
Engineered Nanoparticles ◽  
In Vivo Studies ◽  
Field Exposure ◽  
The Impact

AbstractIn recent years, the introduction of innovative low-cost and large-scale processes for the synthesis of engineered nanoparticles with at least one dimension less than 100 nm has led to countless useful and extensive applications. In this context, gold nanoparticles stimulated a growing interest, due to their peculiar characteristics such as ease of synthesis, chemical stability and optical properties. This stirred the development of numerous applications especially in the biomedical field. Exposure of manufacturers and consumers to industrial products containing nanoparticles poses a potential risk to human health and the environment. Despite this, the precise mechanisms of nanomaterial toxicity have not yet been fully elucidated. It is well known that the three main routes of exposure to nanomaterials are by inhalation, ingestion and through the skin, with inhalation being the most common route of exposure to NPs in the workplace. To provide a complete picture of the impact of inhaled gold nanoparticles on human health, in this article, we review the current knowledge about the physico-chemical characteristics of this nanomaterial, in the size range of 1–100 nm, and its toxicity for pulmonary structures both in vitro and in vivo. Studies comparing the toxic effect of NPs larger than 100 nm (up to 250 nm) are also discussed.

scholarly journals Embryotoxic impact of Zika virus in a rhesus macaque in vitro implantation model†

2020 ◽  
Vol 102 (4) ◽  
pp. 806-816 ◽  
Author(s):  
Lindsey N Block ◽  
Matthew T Aliota ◽  
Thomas C Friedrich ◽  
Michele L Schotzko ◽  
Katherine D Mean ◽  
...  
Keyword(s):  
Rhesus Macaque ◽  
Pregnancy Outcomes ◽  
Zika Virus ◽  
Negative Impact ◽  
Culture Media ◽  
Blastocyst Formation ◽  
Placental Development ◽  
Zikv Infection ◽  
The Impact

Abstract Zika virus (ZIKV) infection is associated with adverse pregnancy outcomes in humans, and infection in the first trimester can lead to miscarriage and stillbirth. Vertical and sexual transmissions of ZIKV have been demonstrated, yet the impact of infection during the initial stages of pregnancy remains unexplored. Here we defined the impact of ZIKV on early embryonic and placental development with a rhesus macaque model. During in vitro fertilization (IVF), macaque gametes were inoculated with a physiologically relevant dose of 5.48log10 plaque-forming units (PFU) of Zika virus/H.sapiens-tc/PUR/2015/PRVABC59_v3c2. Exposure at fertilization did not alter blastocyst formation rates compared to controls. To determine the impact of ZIKV exposure at implantation, hatched blastocysts were incubated with 3.26log10, 4.26log10, or 5.26log10 PFU, or not exposed to ZIKV, followed by extended embryo culture for 10 days. ZIKV exposure negatively impacted attachment, growth, and survival in comparison to controls, with exposure to 5.26log10 PFU ZIKV resulting in embryonic degeneration by day 2. Embryonic secretion of pregnancy hormones was lower in ZIKV-exposed embryos. Increasing levels of infectious virus were detected in the culture media post-exposure, suggesting that the trophectoderm is susceptible to productive ZIKV infection. These results demonstrate that ZIKV exposure severely impacts the zona-free blastocyst, whereas exposure at the time of fertilization does not hinder blastocyst formation. Overall, early stages of pregnancy may be profoundly sensitive to infection and pregnancy loss, and the negative impact of ZIKV infection on pregnancy outcomes may be underestimated.

Tumor Cells Resistant to Alemtuzumab Complement Mediated Cytotoxicity in Patients with High Risk Previously Untreated Early Stage CLL: A Possible Mechanism of Treatment Failure.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2973-2973
Author(s):  
Clive S. Zent ◽  
Nancy D. Bone ◽  
Susan M. Geyer ◽  
Neil E. Kay
Keyword(s):  
Flow Cytometry ◽  
B Cells ◽  
High Risk ◽  
B Cell ◽  
Cell Clone ◽  
Early Stage ◽  
Cell Membrane Permeability ◽  
Viable Cells ◽  
The Impact

Abstract The monoclonal antibodies (MoAb) alemtuzumab and rituximab have proven efficacy in the treatment of CLL. In addition, alemtuzumab is effective in patients with defective p53 function responding poorly to purine analogue therapy. The action of both MoAb is not completely understood. Proposed mechanisms include complement dependent cytotoxicity (CDC), antibody dependent cellular cytotoxicity (ADCC), and direct induction of apoptosis of CLL B cells. We have done correlative studies on CLL B cells from patients enrolled in a trial of alemtuzumab and rituximab in “high risk” early stage previously untreated CLL to determine: 1. Role of apoptosis induction and CDC in each MoAb and 2. If the addition of rituximab to alemtuzumab increases their in vitro cytotoxicity. Patients and Methods: Patients with early stage, previously untreated, high risk CLL are treated with subcutaneous alemtuzumab (dose escalation over 3 days then 30 mg Mon-Wed-Fri for 4 weeks) and rituximab (375 mg/m2/dose weekly from day 8 x 4 doses). High risk disease was defined as one or more of the following features of the CLL B cell clone: (1) 17p13−; (2) 11q22−; (3) unmutated IgVH (&lt; 2%) and either CD38+ or ZAP-70+. Blood B lymphocytes collected prior to the start of therapy were tested for response to MoAb in vitro. Cells were cultured at 2 x 106/ml in AIM-V medium using standard conditions. Alemtuzumab and rituximab were used at 20 μg/ml and complement as 10% of 40 CH50 units/ml human serum. The impact of the MoAb was measured by counting viable cells (trypan blue negative) and measuring early apoptosis (annexin V) and cell death (cell membrane permeability to propidium iodide) using flow cytometry at 1 hour, and then daily for 3 days. Results: Treatment caused rapid resolution of lymphocytosis in all 7 patients and 3 patients were negative for circulating CLL cells using a highly sensitive 3 color flow cytometry (CD5+/CD19+/CD79b-) after therapy. All patients had a clinical response (2 CR, 5 PR). Alemtuzumab and complement were rapidly cytotoxic to most CLL cells. Mean cell viability was 39% (sd: 8%) after 1 hour of incubation. Cytotoxicity was similar in all samples irrespective of FISH defects, IgVH mutation status, and in vitro resistance to F-ara-A (n = 3). Alemtuzumab was inactive in the absence of complement for all samples. Rituximab alone and together with complement did not induce cytotoxicity or apoptosis. However, the addition of rituximab to alemtuzumab and complement did increase CDC where the number of viable cells was significantly lower at 1, 24, 48, and 72 hours incubation (p = 0.075, 0.047, 0.031, 0.027, respectively, for pairwise comparisons). CLL cells surviving alemtuzumab CDC subsequently had a lower level of apoptosis than control cells, implying a selection for resistant cells. Alemtuzumab CDC on this residual population was not increased at higher concentrations of alemtuzumab or complement. This mechanism of CDC resistance is currently under investigation. Conclusion: These data suggest that alemtuzumab CDC is an important mechanism of action in patients with CLL. However, alemtuzumab CDC kills only about 61% of CLL cells in vitro, and the surviving cells are more resistant to spontaneous apoptosis. This suggests that cells that survive alemtuzimab CDC contribute to disease progression or relapse. We intend to elucidate the mechanism of this resistance using our in vitro model with the hope that treatment strategies can be deployed to remove this residual CLL B cell clone.

scholarly journals The Impact of African and Brazilian Zika virus isolates on neuroprogenitors

2016 ◽  
Author(s):  
Loraine Campanati ◽  
Luiza M. Higa ◽  
Rodrigo Delvecchio ◽  
Paula Pezzuto ◽  
Ana Luiza Valadão ◽  
...  
Keyword(s):  
Zika Virus ◽  
Neuroblastoma Cells ◽  
Brazilian Isolate ◽  
Human Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Differentiation Potential ◽  
Neuronal Progenitors ◽  
The Impact ◽  
Virus Isolates

AbstractIn the last few months, an overwhelming number of people have been exposed to the Zika virus (ZIKV) in South and Central America. Here we showed, in vitro, that a Brazilian isolate impacts more severely murine neuronal progenitors and neurons than the African strain MR766. We found that the Brazilian isolate more pronouncedly inhibits neurite extension from neurospheres, alters their differentiation potential and causes neurons to have less and shorter processes. Comparing both lineages using a panel of inflammatory cytokines, we showed, with human neuroblastoma cells, that ZIKV induces the production of several inflammatory and chemotactic cytokines and once again, the Brazilian isolate had a more significant impact. Although much more needs to be studied regarding the association of ZIKV infection and brain damage during development, our study sheds some light into the differences between African and American lineages and the mechanisms by which the virus may be affecting neurogenesis.

scholarly journals The Antidepressant Mirtazapine Rapidly Shifts Hepatic B Cell Populations and Functional Cytokine Signatures in the Mouse

2021 ◽  
Vol 12 ◽  
Author(s):  
Wagdi Almishri ◽  
Rachelle P. Davis ◽  
Abdel-Aziz Shaheen ◽  
Mohammed O. Altonsy ◽  
Craig N. Jenne ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Liver Diseases ◽  
Normal Liver ◽  
Cell Number ◽  
Cell Populations ◽  
Immune Mediated ◽  
B Cell Homeostasis ◽  
The Impact

IntroductionB cells are important regulators of both adaptive and innate immunity. The normal liver contains significant numbers of B cells, and their numbers increase dramatically in immune-mediated liver diseases. Our previous observations suggest a hepatoprotective effect of the antidepressant mirtazapine in human and experimental immune-mediated liver disease. Therefore, we performed a series of experiments to determine the impact of mirtazapine treatment on hepatic B cell homeostasis, as reflected by B cell number, trafficking and phenotype using flow cytometry (FCM) and intravital microscopy (IVM) analysis. Mirtazapine treatment rapidly induced a significant reduction in total hepatic B cell numbers, paralleled by a compositional shift in the predominant hepatic B cell subtype from B2 to B1. This shift in hepatic B cells induced by mirtazapine treatment was associated with a striking increase in total hepatic levels of the chemokine CXCL10, and increased production of CXCL10 by hepatic macrophages and dendritic cells. Furthermore, mirtazapine treatment led to an upregulation of CXCR3, the cognate chemokine receptor for CXCL10, on hepatic B cells that remained in the liver post-mirtazapine. A significant role for CXCR3 in the hepatic retention of B cells post-mirtazapine was confirmed using CXCR3 receptor blockade. In addition, B cells remaining in the liver post-mirtazapine produced lower amounts of the proinflammatory Th1-like cytokines IFNγ, TNFα, and IL-6, and increased amounts of the Th2-like cytokine IL-4, after stimulation in vitro.ConclusionMirtazapine treatment rapidly alters hepatic B cell populations, enhancing hepatic retention of CXCR3-expressing innate-like B cells that generate a more anti-inflammatory cytokine profile. Mirtazapine-induced hepatic B cell shifts could potentially represent a novel therapeutic approach to immune-mediated liver diseases characterized by B cell driven pathology.

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