scholarly journals Molecular Characterization of the Native (Non-Linked) CD160–HVEM Protein Complex Revealed by Initial Crystallographic Analysis

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 820
Author(s):  
Simona Lenhartová ◽  
Marek Nemčovič ◽  
Radka Šebová ◽  
Mário Benko ◽  
Dirk M. Zajonc ◽  
...  
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Cell Activation ◽  
Killer Cell ◽  
Crystallographic Analysis ◽  
Single Chain ◽  
Cell Parameters ◽  
Starting Point ◽  
Wide Range

An increasing number of surface-exposed ligands and receptors acting on immune cells are being considered as a starting point in drug development applications. As they are dedicated to manipulating a wide range of immune responses, accurately predicting their molecular interactions will be necessary for the development of safe and effective therapeutics to enhance immune responses and vaccination. Here, we focused on the characterization of human CD160 and HVEM immune receptors, whose mutual engagement leads to bidirectional signaling (e.g., T cell inhibition, natural killer cell activation or mucosal immunity). In particular, our study reports on the molecule preparation, characterization and initial crystallographic analysis of the CD160–HVEM complex and both HVEM and CD160 in the absence of their binding partner. Despite the importance of the CD160–HVEM immune signaling and its therapeutic relevance, the structural and mechanistic basis underlying CD160–HVEM engagement has some controversial evidence. On one hand, there are studies reporting on the CD160 molecule in monomeric form that was produced by refolding from bacterial cells, or as a covalently linked single-chain complex with its ligand HVEM in insect cells. On the other hand, there are older reports providing evidence on the multimeric form of CD160 that acts directly on immune cells. In our study, the native non-linked CD160–HVEM complex was co-expressed in the baculovirus insect host, purified to homogeneity by anion-exchange chromatography to provide missing evidence of the trimeric form in solution. Its trimeric existence was also confirmed by the initial crystallographic analysis. The native CD160–HVEM complex crystallized in the orthorhombic space group with unit cell parameters that could accommodate one trimeric complex (3:3) in an asymmetric unit, thus providing ample space for the multimeric form. Crystals of the CD160–HVEM complex, CD160 trimer and HVEM monomer (reported in two space groups) diffracted to a minimum Bragg spacing of 2.8, 3.1 and 1.9/2.1 Å resolution, respectively. The obtained data will lead to elucidating the native structure of the complex.

scholarly journals Characterization of the killer cell generated in the autologous mixed leukocyte reaction.

1983 ◽  
Vol 157 (4) ◽  
pp. 1309-1323 ◽  
Author(s):  
M Goto ◽  
N J Zvaifler
Keyword(s):  
T Cell Activation ◽  
Cell Activation ◽  
Killer Cell ◽  
Mixed Leukocyte Reaction ◽  
Killer Activity ◽  
Cytotoxic Cells ◽  
Activation Antigens ◽  
Specific Antigens ◽  
Leu 7

Cytotoxic cells are produced in an autologous mixed leukocyte reaction (AMLR). At 1 wk in culture the AMLR killers are mainly IgG Fc- cells and can kill autologous lymphoblastoid cell lines and Raji and Daudi targets that are usually resistant to natural killer cell (NK) lysis. To define the phenotype of these cells, we have used complement (C')-mediated lysis with monoclonal antibodies (MAb). AMLR killer activity was virtually eliminated by treatment with C' and 9.6 or 4F2, but the cytotoxic cells did not express NK-specific antigens, OKM1 and Leu-7, nor cytolytic T lymphocyte-specific antigens, 9.3 and OKT8. None of the 10 MAb used could significantly block cytotoxicity at the final concentration of 1.5 mcg/ml which is generally sufficient to inhibit CTL. The majority of cells at 1 wk in AMLR cultures stained with T cell activation antigens Ia and 4F2; AMLR killing was proportional to the percentage of 4F2+ cells but unrelated to the expression of Ia antigen.

scholarly journals Vaccine containing immunologic adjuvants with a wide range of activity to provide protection against COVID-19

2021 ◽  
Author(s):  
Mulugeta Berhanu
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Vaccine Development ◽  
Narrow Range ◽  
Wide Spectrum ◽  
Aluminum Salts ◽  
Global Problem ◽  
Wide Range ◽  
Immunologic Adjuvants

This paper proposes a wide spectrum immunologic adjuvant for vaccine development against  COVID-19 which is the current global problem. It has been reported that a wide range of immune cells are involved in the body’s response to SARS CoV2 infection. Therefore, vaccine with a wide-spectrum immunologic adjuvant can be used to provide protection against COVID-19. Lack of adjuvants that can induce the required immune responses is a serious impediment to vaccine development against this devastating virus. The approved adjuvants such as aluminum salts and MF59 exhibit a narrow range of activity. In an attempt to solve this problem, it is crucial to develop new adjuvants which can trigger a wide range of immune cells.

scholarly journals Purification and X-ray crystallographic analysis of 7-keto-8-aminopelargonic acid (KAPA) synthase fromMycobacterium smegmatis

2014 ◽  
Vol 70 (10) ◽  
pp. 1372-1375 ◽  
Author(s):  
Shanghua Fan ◽  
Defeng Li ◽  
Joy Fleming ◽  
Yuan Hong ◽  
Tao Chen ◽  
...  
Keyword(s):  
Crystallographic Analysis ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Essential Enzyme ◽  
Mycobacterial Growth

7-Keto-8-aminopelargonic acid synthase (KAPA synthase; BioF) is an essential enzyme for mycobacterial growth that catalyses the first committed step in the biotin-synthesis pathway. It is a pyridoxal 5′-phosphate (PLP)-dependent enzyme and is a potential drug target. Here, the cloning, expression, purification and crystallization of KAPA synthase fromMycobacterium smegmatis(MsBioF) and the characterization of MsBioF crystals using X-ray diffraction are described. The crystals diffracted to 2.3 Å resolution and belonged to the monoclinic space groupP21, with unit-cell parametersa= 70.88,b= 91.68,c= 109.84 Å, β = 97.8°. According to the molecular weight of MsBioF, the unit-cell parameters and the self-rotation function map, four molecules are present in each asymmetric unit with aVMvalue of 2.06 Å3 Da−1and a solvent content of 40.20%.

scholarly journals Genetic engineering of porcine endothelial cell lines for evaluation of human-to-pig xenoreactive immune responses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ping Li ◽  
Julia R. Walsh ◽  
Kevin Lopez ◽  
Abdulkadir Isidan ◽  
Wenjun Zhang ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Immune Responses ◽  
Cell Activation ◽  
Killer Cell ◽  
Genetically Engineered ◽  
Organ Shortage ◽  
Human Natural Killer Cell ◽  
Genetic Modifications ◽  
Porcine Endothelial Cell

AbstractXenotransplantation (cross-species transplantation) using genetically-engineered pig organs offers a potential solution to address persistent organ shortage. Current evaluation of porcine genetic modifications is to monitor the nonhuman primate immune response and survival after pig organ xenotransplantation. This measure is an essential step before clinical xenotransplantation trials, but it is time-consuming, costly, and inefficient with many variables. We developed an efficient approach to quickly examine human-to-pig xeno-immune responses in vitro. A porcine endothelial cell was characterized and immortalized for genetic modification. Five genes including GGTA1, CMAH, β4galNT2, SLA-I α chain, and β2-microglobulin that are responsible for the production of major xenoantigens (αGal, Neu5Gc, Sda, and SLA-I) were sequentially disrupted in immortalized porcine endothelial cells using CRISPR/Cas9 technology. The elimination of αGal, Neu5Gc, Sda, and SLA-I dramatically reduced the antigenicity of the porcine cells, though the cells still retained their ability to provoke human natural killer cell activation. In summary, evaluation of human immune responses to genetically modified porcine cells in vitro provides an efficient method to identify ideal combinations of genetic modifications for improving pig-to-human compatibility, which should accelerate the application of xenotransplantation to humans.

scholarly journals Vaccine containing immunologic adjuvants with a wide range of activity to provide protection against COVID-19

2021 ◽  
Author(s):  
Mulugeta Berhanu
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Vaccine Development ◽  
Narrow Range ◽  
Wide Spectrum ◽  
Aluminum Salts ◽  
Global Problem ◽  
Wide Range ◽  
Immunologic Adjuvants

This paper proposes a wide spectrum immunologic adjuvant for vaccine development against COVID-19 which is the current global problem. It has been reported that a wide range of immune cells are involved in the body's response to SARS CoV2 infection. Therefore, vaccine with a wide-spectrum immunologic adjuvant can be used to provide protection against COVID-19. Lack of adjuvants that can induce the required immune responses is a serious impediment to vaccine development against this devastating virus. The approved adjuvants such as aluminum salts and MF59 exhibit a narrow range of activity. In an attempt to solve this problem, it is crucial to develop new adjuvants which can trigger a wide range of immune cells.

scholarly journals Macrophages and the maintenance of homeostasis

2020 ◽  
Author(s):  
David M. Mosser ◽  
Kajal Hamidzadeh ◽  
Ricardo Goncalves
Keyword(s):  
Immune Responses ◽  
Immune Cells ◽  
Macrophage Polarization ◽  
The Body ◽  
Sensory Stimuli ◽  
Cellular Processes ◽  
Wide Range ◽  
Tissue Responses ◽  
Different Response

Abstract There have been many chapters written about macrophage polarization. These chapters generally focus on the role of macrophages in orchestrating immune responses by highlighting the T-cell-derived cytokines that shape these polarizing responses. This bias toward immunity is understandable, given the importance of macrophages to host defense. However, macrophages are ubiquitous and are involved in many different cellular processes, and describing them as immune cells is undoubtedly an oversimplification. It disregards their important roles in development, tissue remodeling, wound healing, angiogenesis, and metabolism, to name just a few processes. In this chapter, we propose that macrophages function as transducers in the body. According to Wikipedia, “A transducer is a device that converts energy from one form to another.” The word transducer is a term used to describe both the “sensor,” which can interpret a wide range of energy forms, and the “actuator,” which can switch voltages or currents to affect the environment. Macrophages are able to sense a seemingly endless variety of inputs from their environment and transduce these inputs into a variety of different response outcomes. Thus, rather than functioning as immune cells, they should be considered more broadly as cellular transducers that interpret microenvironmental changes and actuate vital tissue responses. In this chapter, we will describe some of the sensory stimuli that macrophages perceive and the responses they make to these stimuli to achieve their prime directive, which is the maintenance of homeostasis.

scholarly journals From Anti-SARS-CoV-2 Immune Responses to COVID-19 via Molecular Mimicry

Antibodies ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 33 ◽  
Author(s):  
Darja Kanduc
Keyword(s):  
Immune Responses ◽  
Molecular Mimicry ◽  
Multiple Organ ◽  
Protein Targets ◽  
Immune Epitope ◽  
Clinical Investigations ◽  
Starting Point ◽  
Wide Range ◽  
Human Proteins ◽  
Immune Epitope Database

Aim: To define the autoimmune potential of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Methods: Experimentally validated epitopes cataloged at the Immune Epitope DataBase (IEDB) and present in SARS-CoV-2 were analyzed for peptide sharing with the human proteome. Results: Immunoreactive epitopes present in SARS-CoV-2 were mostly composed of peptide sequences present in human proteins that—when altered, mutated, deficient or, however, improperly functioning—may associate with a wide range of disorders, from respiratory distress to multiple organ failure. Conclusions: This study represents a starting point or hint for future scientific–clinical investigations and suggests a range of possible protein targets of autoimmunity in SARS-CoV-2 infection. From an experimental perspective, the results warrant the testing of patients’ sera for autoantibodies against these protein targets. Clinically, the results warrant a stringent surveillance on the future pathologic sequelae of the current SARS-CoV-2 pandemic.

scholarly journals Purification, crystallization and preliminary crystallographic analysis of Gan1D, a GH1 6-phospho-β-galactosidase fromGeobacillus stearothermophilusT1

2014 ◽  
Vol 70 (2) ◽  
pp. 225-231 ◽  
Author(s):  
Shifra Lansky ◽  
Arie Zehavi ◽  
Roie Dann ◽  
Hay Dvir ◽  
Hassan Belrhali ◽  
...  
Keyword(s):  
Plant Cell Wall ◽  
Extracellular Enzymes ◽  
Biochemical Characterization ◽  
Crystal Structure Analysis ◽  
Crystallographic Analysis ◽  
Glycoside Hydrolases ◽  
Cell Wall Polysaccharides ◽  
Data Set ◽  
Cell Parameters ◽  
Wide Range

Geobacillus stearothermophilusT1 is a Gram-positive thermophilic soil bacterium that contains an extensive system for the utilization of plant cell-wall polysaccharides, including xylan, arabinan and galactan. The bacterium uses a number of extracellular enzymes that break down the high-molecular-weight polysaccharides into short oligosaccharides, which enter the cell and are further hydrolyzed into sugar monomers by dedicated intracellular glycoside hydrolases. The interest in the biochemical characterization and structural analysis of these proteins originates mainly from the wide range of their potential biotechnological applications. Studying the different hemicellulolytic utilization systems inG. stearothermophilusT1, a new galactan-utilization gene cluster was recently identified, which encodes a number of proteins, one of which is a GH1 putative 6-phospho-β-galactosidase (Gan1D). Gan1D has recently been cloned, overexpressed, purified and crystallized as part of its comprehensive structure–function study. The best crystals obtained for this enzyme belonged to the triclinic space groupP1, with average crystallographic unit-cell parameters ofa = 67.0,b= 78.1,c= 92.1 Å, α = 102.4, β = 93.5, γ = 91.7°. A full diffraction data set to 1.33 Å resolution has been collected for the wild-type enzyme, as measured from flash-cooled crystals at 100 K, using synchrotron radiation. These data are currently being used for the detailed three-dimensional crystal structure analysis of Gan1D.

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