scholarly journals Identification of Protective Lassa Virus Epitopes That Are Restricted by HLA-A2

2006 ◽  
Vol 80 (17) ◽  
pp. 8351-8361 ◽  
Author(s):  
Jason Botten ◽  
Jeff Alexander ◽  
Valerie Pasquetto ◽  
John Sidney ◽  
Polly Barrowman ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Sequence Data ◽  
Recombinant Vaccinia Virus ◽  
Target Cells ◽  
Lassa Virus ◽  
Primary Role ◽  
Emerging Pathogens ◽  
Glycoprotein Precursor ◽  
Predictive Algorithm ◽  
Positive Target

ABSTRACT Recovery from Lassa virus (LASV) infection usually precedes the appearance of neutralizing antibodies, indicating that cellular immunity plays a primary role in viral clearance. To date, the role of LASV-specific CD8+ T cells has not been evaluated in humans. To facilitate such studies, we utilized a predictive algorithm to identify candidate HLA-A2 supertype epitopes from the LASV nucleoprotein and glycoprotein precursor (GPC) genes. We identified three peptides (GPC42-50, GLVGLVTFL; GPC60-68, SLYKGVYEL; and GPC441-449, YLISIFLHL) that displayed high-affinity binding (≤98 nM) to HLA-A*0201, induced CD8+ T-cell responses of high functional avidity in HLA-A*0201 transgenic mice, and were naturally processed from native LASV GPC in human HLA-A*0201-positive target cells. HLA-A*0201 mice immunized with either GPC42-50 or GPC60-68 were protected against challenge with a recombinant vaccinia virus that expressed LASV GPC. The epitopes identified in this study represent potential diagnostic reagents and candidates for inclusion in epitope-based vaccine constructs. Our approach is applicable to any pathogen with existing sequence data, does not require manipulation of the actual pathogen or access to immune human donors, and should therefore be generally applicable to category A through C agents and other emerging pathogens.

scholarly journals HLA-A2-Restricted Protection against Lethal Lymphocytic Choriomeningitis

2006 ◽  
Vol 81 (5) ◽  
pp. 2307-2317 ◽  
Author(s):  
Jason Botten ◽  
J. Lindsay Whitton ◽  
Polly Barrowman ◽  
John Sidney ◽  
Jason K. Whitmire ◽  
...  
Keyword(s):  
T Cells ◽  
Transgenic Mice ◽  
Lymphocytic Choriomeningitis ◽  
Target Cells ◽  
Primary Role ◽  
Protein Z ◽  
Glycoprotein Precursor ◽  
Antigen Presenting ◽  
Lcmv Infection

ABSTRACT The consequences of human lymphocytic choriomeningitis virus (LCMV) infection can be severe, including aseptic meningitis in immunocompetent individuals, hydrocephalus or chorioretinitis in fetal infection, or a highly lethal outcome in immunosuppressed individuals. In murine models of LCMV infection, CD8+ T cells play a primary role in providing protective immunity, and there is evidence that cellular immunity may also be important in related arenavirus infections in humans. For this reason, we sought to identify HLA-A2 supertype-restricted epitopes from the LCMV proteome and evaluate them as vaccine determinants in HLA transgenic mice. We identified four HLA-A*0201-restricted peptides—nucleoprotein NP69-77, glycoprotein precursor GPC10-18, GPC447-455, and zinc-binding protein Z49-58—that displayed high-affinity binding (≤275 nM) to HLA-A*0201, induced CD8+ T-cell responses of high functional avidity in HLA-A*0201 transgenic mice, and were naturally processed from native LCMV antigens in HLA-restricted human antigen presenting cells. One of the epitopes (GPC447-455), after peptide immunization of HLA-A*0201 mice, induced CD8+ T cells capable of killing peptide-pulsed HLA-A*0201-restricted target cells in vivo and protected mice against lethal intracranial challenge with LCMV.

scholarly journals Analysis of The Nucleotide Sequence Diversity of the Lassa Virus and Augmenting its Phylogenetic Tree

2018 ◽  
Vol 4 (1) ◽  
pp. 21-26
Author(s):  
Sean Oddoye
Keyword(s):  
Phylogenetic Tree ◽  
Phylogenetic Trees ◽  
Nucleotide Diversity ◽  
Sequence Data ◽  
Sequence Diversity ◽  
Future Research ◽  
P Value ◽  
Hemorrhagic Disease ◽  
Lassa Virus ◽  
Glycoprotein Precursor

Lassa Virus (LASV) is the etiological catalyst for Lassa fever, an acute hemorrhagic disease with a mortality rate of 15%. Many aspects of the Lassa virus are not understood, like the causation of deafness in ⅓ of surviving patients or why symptoms are benign for 80% of those infected with the virus. Ambiguities like these suggest that there might exist some genomic heterogeneity among infecting viruses and demonstrate a need to quantify and analyze polymorphisms within LASV. Patterns that emerge from phylogenetic trees can be used to assess the structure of a population while also providing insights to the genetic makeup. The purpose of this investigation was to develop a more streamlined means of calculating nucleotide diversity within a subpopulation of Lassa virus strains and to augment a phylogenetic tree of the Lassa Virus glycoprotein precursor (GPC) segment. A total of 25 partial and complete data sequences of LASV strains were obtained from the Genbank Archives. During phase one of this investigation, the sequence data was inputted into MEGA analytical software and the sequence diversity was derived on a nucleotide level. Data from the individual strand sequences was used to augment a phylogenetic tree using Treeview X software. In phase two of this investigation, an algorithm was created using RStudio, with BSGenome and BioStrings extensions. The sequence diversity derived from the statistical analyses on MEGA was compared to that of the algorithm created. A p-value of 0.08 was found, which deviates from the accepted range of non-medical p-value of 0.00 to 0.05. It is suggested that future research focuses on creating a refurbished version of the algorithm to calculate a nucleotide diversity within a percent error of 5%.

Homologous and heterologous glycoproteins induce protection against Junin virus challenge in guinea pigs

Microbiology ◽  
2000 ◽  
Vol 81 (5) ◽  
pp. 1273-1281 ◽  
Author(s):  
Nora López ◽  
Luis Scolaro ◽  
Carlos Rossi ◽  
Rodrigo Jácamo ◽  
Nélida Candurra ◽  
...  
Keyword(s):  
Vaccinia Virus ◽  
Guinea Pigs ◽  
Neutralizing Antibodies ◽  
Recombinant Vaccinia Virus ◽  
Glycoprotein Precursor ◽  
Lethal Challenge ◽  
Recombinant Vaccinia ◽  
Junin Virus ◽  
Virus Challenge ◽  
Junín Virus

Tacaribe virus (TACV) is an arenavirus that is genetically and antigenically closely related to Junin virus (JUNV), the aetiological agent of Argentine haemorrhagic fever (AHF). It is well established that TACV protects experimental animals fully against an otherwise lethal challenge with JUNV. To gain information on the nature of the antigens involved in cross-protection, recombinant vaccinia viruses were constructed that express the glycoprotein precursor (VV–GTac) or the nucleocapsid protein (VV–N) of TACV. TACV proteins expressed by vaccinia virus were indistinguishable from authentic virus proteins by gel electrophoresis. Guinea pigs inoculated with VV–GTac or VV–N elicited antibodies that immunoprecipitated authentic TACV proteins. Antibodies generated by VV–GTac neutralized TACV infectivity. Levels of antibodies after priming and boosting with recombinant vaccinia virus were comparable to those elicited in TACV infection. To evaluate the ability of recombinant vaccinia virus to protect against experimental AHF, guinea pigs were challenged with lethal doses of JUNV. Fifty per cent of the animals immunized with VV–GTac survived, whereas all animals inoculated with VV–N or vaccinia virus died. Having established that the heterologous glycoprotein protects against JUNV challenge, a recombinant vaccinia virus was constructed that expresses JUNV glycoprotein precursor (VV–GJun). The size and reactivity to monoclonal antibodies of the vaccinia virus-expressed and authentic JUNV glycoproteins were indistinguishable. Seventy-two per cent of the animals inoculated with two doses of VV–GJun survived lethal JUNV challenge. Protection with either VV–GJun or VV–GTac occurred in the presence of low or undetectable levels of neutralizing antibodies to JUNV.

scholarly journals Structural study of the transmembrane and membrane proximal domains of HIV-1 gp41

2014 ◽  
Vol 70 (a1) ◽  
pp. C122-C122
Author(s):  
Zhen Gong ◽  
Raimund Fromme ◽  
Felicia Craciunescu ◽  
Tsafrir Mor ◽  
Petra Fromme ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Proximal Region ◽  
Target Cells ◽  
Primary Role ◽  
Biological Functions ◽  
Broadly Neutralizing Antibodies ◽  
Mucosal Transmission ◽  
C Terminus ◽  
Tm Domain ◽  
Hiv 1

The transmembrane subunit (gp41) of the envelope glycoprotein (Env) of HIV-1 associates non-covalently with the surface subunit (gp120) and together they play essential roles in viral mucosal transmission and infection of target cells. The membrane proximal region (MPR) of gp41 is highly conserved and contains epitopes of broadly neutralizing antibodies. The transmembrane (TM) domain of gp41 is involved in many essential biological functions and its primary role is to anchor the Env in both viral and cellular membranes. Despite having many important biological functions, the atomic structure of gp41 TM domain remains unknown. While high-resolution X-ray structures of some segments of the MPR were solved in the past, they represent the prefusion or post-fusion conformations, which could not be recognized by the broadly neutralizing antibodies 2F5 and 4E10. Here we describe the expression, purification, biophysical characterization and crystallization of a chimera construct including maltose binding protein (MBP) and MPR-TM of gp41. The purified MBP-MPR-TM protein reacts with the broadly neutralizing antibodies 2F5 and 4E10 with nanomolar affinities and thereby may represent an immunologically relevant conformation mimicking a pre-hairpin intermediate of gp41. Crystals could not be obtained initially when MPR-TM was fused to the C terminus of MBP with linker 1 (MBP-linker1-MPR-TM) but could be obtained after changing the linker (MBP-linker2-MPR-TM). The crystal belongs to space group P32 with unit cell constants of a=172 Å, b=172 Å, c= 70 Å and alpha=beta=90 and gamma=120. The 2.5 Å crystal structure reveals the conformation of MBP and part of the linker region of this chimera, but the MPR-TM segment is unstructured.

scholarly journals Immunization with Epstein–Barr Virus Core Fusion Machinery Envelope Proteins Elicit High Titers of Neutralizing Activities and Protect Humanized Mice from Lethal Dose EBV Challenge

Vaccines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 285
Author(s):  
Xinle Cui ◽  
Zhouhong Cao ◽  
Yuriko Ishikawa ◽  
Sara Cui ◽  
Ken-Ichi Imadome ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
B Lymphocytes ◽  
Neutralizing Antibodies ◽  
Epstein Barr Virus ◽  
Lethal Dose ◽  
Envelope Proteins ◽  
Humanized Mice ◽  
Target Cells ◽  
Barr Virus ◽  
Epstein Barr

Epstein–Barr virus (EBV) is the primary cause of infectious mononucleosis and is strongly implicated in the etiology of multiple lymphoid and epithelial cancers. EBV core fusion machinery envelope proteins gH/gL and gB coordinately mediate EBV fusion and entry into its target cells, B lymphocytes and epithelial cells, suggesting these proteins could induce antibodies that prevent EBV infection. We previously reported that the immunization of rabbits with recombinant EBV gH/gL or trimeric gB each induced markedly higher serum EBV-neutralizing titers for B lymphocytes than that of the leading EBV vaccine candidate gp350. In this study, we demonstrated that immunization of rabbits with EBV core fusion machinery proteins induced high titer EBV neutralizing antibodies for both B lymphocytes and epithelial cells, and EBV gH/gL in combination with EBV trimeric gB elicited strong synergistic EBV neutralizing activities. Furthermore, the immune sera from rabbits immunized with EBV gH/gL or trimeric gB demonstrated strong passive immune protection of humanized mice from lethal dose EBV challenge, partially or completely prevented death respectively, and markedly decreased the EBV load in peripheral blood of humanized mice. These data strongly suggest the combination of EBV core fusion machinery envelope proteins gH/gL and trimeric gB is a promising EBV prophylactic vaccine.

scholarly journals Prostaglandin E2 Affects Differently the Release of Inflammatory Mediators from Resident Macrophages by LPS and Muramyl Tripeptides

1999 ◽  
Vol 8 (6) ◽  
pp. 295-303 ◽  
Author(s):  
Peter Dieter ◽  
Ute Hempel ◽  
Sabine Kamionka ◽  
Angelika Kolada ◽  
Birgit Malessa ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Transcription Factors ◽  
Map Kinase ◽  
Kupffer Cells ◽  
Neutralizing Antibodies ◽  
Target Cells ◽  
Tnf Α ◽  
Extracellular Regulated Kinase ◽  
Oxide Synthase ◽  
Rapid Activation

LPS and MTP-PE (liposome-encapsulatedN-acetylmuramyl-L-alanyl-D-isoglutaminyl-L-alanine-2-:[1',2'-dipalmitoyl-sni-glycero-3-(hydroxy-phosphoryl-oxyl)] etylamide) induce in liver macrophages a synthesis and release of TNF-α, nitric oxide and prostanoids. Both agents induce an expression of mRNA's encoding TNF-α, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and of corresponding proteins. LPS and MTP-PE induce a rapid activation of the extracellular regulated kinase (ERK) isoenzymes-1 and -2. Inhibition of map kinase isoenzymes leads to a decreased release of TNF-α, nitric oxide and prostaglandin (PG) E2after both agents. The transcription factors NF-κB and AP-1 are strongly activated by LPS within 30 minutes. MTP-PE induces a weak activation of both transcription factors only after 5 hours. Inhibition of NF-κB inhibits the LPS- but not the MTP-PE-induced release of TNF-α, nitric oxide and PGE2. PGE2release after LPS is higher than after MTP-PE. Exogenously added PGE2inhibits the activation of map kinase and TNF-α release by LPS, but not by MTP-PE. Release of nitric oxide after LPS and MTP-PE is enhanced after prior addition of PGE2. PGD2is without any effect. MTP-PE, but not LPS, induces a cytotoxicity of Kupffer cells against P815 tumor target cells. The MTP-PE-induced cytotoxicity is reduced by TNF-α neutralizing antibodies, indicating the involvement of TNF-α. Thus our results suggest that the different potencies of LPS and MTP-PE as immunomodulators probably result from different actions on Kupffer cells, resulting in differences in the amounts and kinetics of released TNF-α and PGE2, and that PGE2plays an important regulatory role in the action of LPS, but not in the actions of MTP-PE.

scholarly journals Characterization of Lassa Virus Cell Entry and Neutralization with Lassa Virus Pseudoparticles

2009 ◽  
Vol 83 (7) ◽  
pp. 3228-3237 ◽  
Author(s):  
François-Loic Cosset ◽  
Philippe Marianneau ◽  
Geraldine Verney ◽  
Fabrice Gallais ◽  
Noel Tordo ◽  
...  
Keyword(s):  
Immune Response ◽  
Humoral Immune Response ◽  
Neutralizing Antibodies ◽  
Cell Attachment ◽  
Low Ph ◽  
Cell Entry ◽  
Lassa Virus ◽  
Ph Optimum ◽  
Humoral Immune

ABSTRACT The cell entry and humoral immune response of the human pathogen Lassa virus (LV), a biosafety level 4 (BSL4) Old World arenavirus, are not well characterized. LV pseudoparticles (LVpp) are a surrogate model system that has been used to decipher factors and routes involved in LV cell entry under BSL2 conditions. Here, we describe LVpp, which are highly infectious, with titers approaching those obtained with pseudoparticles displaying G protein of vesicular stomatitis virus and their the use for the characterization of LV cell entry and neutralization. Upon cell attachment, LVpp utilize endocytic vesicles for cell entry as described for many pH-dependent viruses. However, the fusion of the LV glycoproteins is activated at unusually low pH values, with optimal fusion occurring between pH 4.5 and 3, a pH range at which fusion characteristics of viral glycoproteins have so far remained largely unexplored. Consistent with a shifted pH optimum for fusion activation, we found wild-type LV and LVpp to display a remarkable resistance to exposure to low pH. Finally, LVpp allow the fast and quantifiable detection of neutralizing antibodies in human and animal sera and will thus facilitate the study of the humoral immune response in LV infections.

scholarly journals Absence of allogeneic restriction in human T-cell-mediated cytotoxicity to Epstein-Barr virus-infected target cells. Demonstration of an HLA-linked control at the effector level.

1979 ◽  
Vol 150 (6) ◽  
pp. 1310-1322 ◽  
Author(s):  
M Lipinski ◽  
W H Fridman ◽  
T Tursz ◽  
C Vincent ◽  
D Pious ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
Cell Surface ◽  
Target Cell ◽  
Epstein Barr Virus ◽  
Target Cells ◽  
Specific Lysis ◽  
Barr Virus ◽  
Positive Target ◽  
Epstein Barr

Peripheral T lymphocytes from patients with infectious mononucleosis (IM) are sensitized in vivo against the Epstein-Barr virus (EBV). The expression of HLA-A, B, or C molecules at the target cell surface is necessary for the cytotoxic reaction because (a) EBV-positive Daudi cells lacking HLA-A, B, and C determinants are resistant to anti-EBV T-cell lysis, (b) cytolysis of EBV-positive target cells can be consistently inhibited by anti-HLA-A, B, and C and anti-beta 2 microglobulin antibodies. However, no evidence for allogeneic restriction in this system was apparent as (a) cytotoxic T lymphocytes (CTL) from one given individual could exert a cytotoxicity of a similar magnitude on different EBV-positive target cells, regardless of the number of HLA-A or B specificities shared by the effectors and targets; (b) CTL from IM patients were able to kill target cells without any HLA-A or B antigen in common; and (c) T5-1 variants lacking one or two HLA antigens at the A, B, or D locus are killed to the same extent as the parental cells. 7 of the 9 IM patients with detectable circulating anti-EBV CTL carried the HLA-A1 antigen, whereas none of the 16 IM patients lacking detectable peripheral CTL were HLA-A1 positive (mean specific lysis of T5-1 target cells by T cells from HLA-A1 positive patients: 29.3 vs. 0.6% in HLA-A1-negative patients) (P less than 10(-9)). These data suggest an HLA-A1-linked gene control of the magnitude of the anti-EBV CTL response. Thus, the HLA region appears to act at two different level sin the T-cell-mediated lysis of EBV-infected cells by controlling first, the development of anti-EBV and second, the expression of HLA-A, B, and C molecules involved as recognition structures at the target cell surface.

scholarly journals In Vitro and In Vivo Comparison of Lymphocytes Transduced with a Human CD16 or with a Chimeric Antigen Receptor Reveals Potential Off-Target Interactions due to the IgG2 CH2-CH3 CAR-Spacer

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Béatrice Clémenceau ◽  
Sandrine Valsesia-Wittmann ◽  
Anne-Catherine Jallas ◽  
Régine Vivien ◽  
Raphaël Rousseau ◽  
...  
Keyword(s):  
Chimeric Antigen Receptor ◽  
Tumor Regression ◽  
Critical Role ◽  
Antigen Receptor ◽  
Target Cells ◽  
Cytotoxic Lymphocytes ◽  
Her2 Positive ◽  
Positive Target

The present work was designed to compare two mechanisms of cellular recognition based on Ab specificity: firstly, when the anti-HER2 mAb trastuzumab bridges target cells and cytotoxic lymphocytes armed with a Fc receptor (ADCC) and, secondly, when HER2 positive target cells are directly recognized by cytotoxic lymphocytes armed with a chimeric antigen receptor (CAR). To compare these two mechanisms, we used the same cellular effector (NK-92) and the same signaling domain (FcεRIγ). The NK-92 cytotoxic cell line was transfected with either a FcγRIIIa-FcεRIγ(NK-92CD16) or a trastuzumab-based scFv-FcεRIγchimeric receptor (NK-92CAR). In vitro, the cytotoxic activity against HER2 positive target cells after indirect recognition byNK-92CD16was always inferior to that observed after direct recognition byNK-92CAR. In contrast, and somehow unexpectedly, in vivo, adoptive transfer ofNK-92CD16+ trastuzumab but not ofNK-92CARinduced tumor regression. Analysis of the in vivo xenogeneic system suggested that the human CH2-CH3 IgG2 used as a spacer in our construct was able to interact with the FcR present at the cell surface of the few NSG-FcR+ remaining immune cells. This interaction, leading to blockage of theNK-92CARin the periphery of the engrafted tumor cells, stresses the critical role of the composition of the spacer domain.

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