scholarly journals Antibody Escape Kinetics of Equine Infectious Anemia Virus Infection of Horses

2015 ◽  
Vol 89 (13) ◽  
pp. 6945-6951 ◽  
Author(s):  
Elissa J. Schwartz ◽  
Seema Nanda ◽  
Robert H. Mealey
Keyword(s):  
Neutralizing Antibodies ◽  
Equine Infectious Anemia Virus ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Fitness Costs ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Kinetics Of ◽  
Virus Fitness

Lentivirus escape from neutralizing antibodies (NAbs) is not well understood. In this work, we quantified antibody escape of a lentivirus, using antibody escape data from horses infected with equine infectious anemia virus. We calculated antibody blocking rates of wild-type virus, fitness costs of mutant virus, and growth rates of both viruses. These quantitative kinetic estimates of antibody escape are important for understanding lentiviral control by antibody neutralization and in developing NAb-eliciting vaccine strategies.

scholarly journals Kinetics of Neutralizing Antibodies of COVID-19 Patients Tested Using Clinical D614G, B.1.1.7 and B 1.351 Isolates in Microneutralization Assays

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 996
Author(s):  
Jenni Virtanen ◽  
Ruut Uusitalo ◽  
Essi M. Korhonen ◽  
Kirsi Aaltonen ◽  
Teemu Smura ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Acute Infection ◽  
Clinical Isolates ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Kinetics Of

Increasing evidence suggests that some newly emerged SARS-CoV-2 variants of concern (VoCs) resist neutralization by antibodies elicited by the early-pandemic wild-type virus. We applied neutralization tests to paired recoveree sera (n = 38) using clinical isolates representing the first wave (D614G), VoC1, and VoC2 lineages (B.1.1.7 and B 1.351). Neutralizing antibodies inhibited contemporary and VoC1 lineages, whereas inhibition of VoC2 was reduced 8-fold, with 50% of sera failing to show neutralization. These results provide evidence for the increased potential of VoC2 to reinfect previously SARS-CoV-infected individuals. The kinetics of NAbs in different patients showed similar decline against all variants, with generally low initial anti-B.1.351 responses becoming undetectable, but with anti-B.1.1.7 NAbs remaining detectable (>20) for months after acute infection.

scholarly journals Equine Infectious Anemia Virus Entry Occurs through Clathrin-Mediated Endocytosis

2007 ◽  
Vol 82 (4) ◽  
pp. 1628-1637 ◽  
Author(s):  
Melinda A. Brindley ◽  
Wendy Maury
Keyword(s):  
Viral Entry ◽  
Equine Infectious Anemia Virus ◽  
Low Ph ◽  
Endocytic Pathway ◽  
Wild Type Virus ◽  
Wild Type ◽  
Coated Pits ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
In Cells

ABSTRACT Entry of wild-type lentivirus equine infectious anemia virus (EIAV) into cells requires a low-pH step. This low-pH constraint implicates endocytosis in EIAV entry. To identify the endocytic pathway involved in EIAV entry, we examined the entry requirements for EIAV into two different cells: equine dermal (ED) cells and primary equine endothelial cells. We investigated the entry mechanism of several strains of EIAV and found that both macrophage-tropic and tissue culture-adapted strains utilize clathrin-coated pits for entry. In contrast, a superinfecting strain of EIAV, EIAVvMA-1c, utilizes two mechanisms of entry. In cells such as ED cells that EIAVvMA-1c is able to superinfect, viral entry is pH independent and appears to be mediated by plasma membrane fusion, whereas in cells where no detectable superinfection occurs, EIAVvMA-1c entry that is low-pH dependent occurs through clathrin-coated pits in a manner similar to wild-type virus. Regardless of the mechanism of entry being utilized, the internalization kinetics of EIAV is rapid with 50% of cell-associated virions internalizing within 60 to 90 min. Cathepsin inhibitors did not prevent EIAV entry, suggesting that the low-pH step required by wild-type EIAV is not required to activate cellular cathepsins.

scholarly journals Modelling Mutation in Equine Infectious Anemia Virus Infection Suggests a Path to Viral Clearance with Repeated Vaccination

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2450
Author(s):  
Elissa J. Schwartz ◽  
Christian Costris-Vas ◽  
Stacey R. Smith
Keyword(s):  
Virus Infection ◽  
Equine Infectious Anemia Virus ◽  
Experimental Studies ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Wild Type ◽  
Data Set ◽  
Mutant Strains ◽  
Equine Infectious Anemia ◽  
Anemia Virus

Equine Infectious Anemia Virus (EIAV) is a lentivirus similar to HIV that infects horses. Clinical and experimental studies demonstrating immune control of EIAV infection hold promise for efforts to produce an HIV vaccine. Antibody infusions have been shown to block both wild-type and mutant virus infection, but the mutant sometimes escapes. Using these data, we develop a mathematical model that describes the interactions between antibodies and both wild-type and mutant virus populations, in the context of continual virus mutation. The aim of this work is to determine whether repeated vaccinations through antibody infusions can reduce both the wild-type and mutant strains of the virus below one viral particle, and if so, to examine the vaccination period and number of infusions that ensure eradication. The antibody infusions are modelled using impulsive differential equations, a technique that offers insight into repeated vaccination by approximating the time-to-peak by an instantaneous change. We use impulsive theory to determine the maximal vaccination intervals that would be required to reduce the wild-type and mutant virus levels below one particle per horse. We show that seven boosts of the antibody vaccine are sufficient to eradicate both the wild-type and the mutant strains. In the case of a mutant virus infection that is given infusions of antibodies targeting wild-type virus (i.e., simulation of a heterologous infection), seven infusions were likewise sufficient to eradicate infection, based upon the data set. However, if the period between infusions was sufficiently increased, both the wild-type and mutant virus would eventually persist in the form of a periodic orbit. These results suggest a route forward to design antibody-based vaccine strategies to control viruses subject to mutant escape.

scholarly journals Specificity of serum neutralizing antibodies induced by transient immune suppression of inapparent carrier ponies infected with a neutralization-resistant equine infectious anemia virus envelope strain

2005 ◽  
Vol 86 (1) ◽  
pp. 139-149 ◽  
Author(s):  
Laryssa Howe ◽  
Jodi K. Craigo ◽  
Charles J. Issel ◽  
Ronald C. Montelaro
Keyword(s):  
Immune Suppression ◽  
Neutralizing Antibodies ◽  
Equine Infectious Anemia Virus ◽  
Antibody Responses ◽  
Serum Antibodies ◽  
Virus Envelope ◽  
Specific Serum ◽  
Surface Envelope ◽  
Equine Infectious Anemia ◽  
Anemia Virus

It has been previously reported that transient corticosteroid immune suppression of ponies experimentally infected with a highly neutralization resistant envelope variant of equine infectious anemia virus (EIAV), designated EIAVΔPND, resulted in the appearance of type-specific serum antibodies to the infecting EIAVΔPND virus. The current study was designed to determine if this induction of serum neutralizing antibodies was associated with changes in the specificity of envelope determinants targeted by serum antibodies or caused by changes in the nature of the antibodies targeted to previously defined surface envelope gp90 V3 and V4 neutralization determinants. To address this question, the envelope determinants of neutralization by post-immune suppression serum were mapped. The results demonstrated that the neutralization sensitivity to post-immune suppression serum antibodies mapped specifically to the surface envelope gp90 V3 and V4 domains, individually or in combination. Thus, these data indicate that the development of serum neutralizing antibodies to the resistant EIAVΔPND was due to an enhancement of host antibody responses caused by transient immune suppression and the associated increase in virus replication.

scholarly journals Transient kinetics of ligand binding and role of the C-terminus in the dUTPase from equine infectious anemia virus

FEBS Letters ◽  
2000 ◽  
Vol 472 (2-3) ◽  
pp. 312-316 ◽  
Author(s):  
Johan Nord ◽  
Martin Kiefer ◽  
Hans-Werner Adolph ◽  
Michael M. Zeppezauer ◽  
Per-Olof Nyman
Keyword(s):  
Ligand Binding ◽  
Equine Infectious Anemia Virus ◽  
Transient Kinetics ◽  
C Terminus ◽  
Equine Infectious Anemia ◽  
Anemia Virus ◽  
Kinetics Of

scholarly journals An Equine Infectious Anemia Virus Variant Superinfects Cells through Novel Receptor Interactions

2008 ◽  
Vol 82 (19) ◽  
pp. 9425-9432 ◽  
Author(s):  
Melinda A. Brindley ◽  
Baoshan Zhang ◽  
Ronald C. Montelaro ◽  
Wendy Maury
Keyword(s):  
Endothelial Cells ◽  
Equine Infectious Anemia Virus ◽  
Cell Monolayer ◽  
Wild Type ◽  
Virus Variant ◽  
Receptor Interactions ◽  
Equine Infectious Anemia ◽  
Infected Cells ◽  
Anemia Virus ◽  
Type Strains

ABSTRACT Wild-type strains of equine infectious anemia virus (EIAV) prevent superinfection of previously infected cells. A variant strain of virus that spontaneously arose during passage, EIAVvMA-1c, can circumvent this mechanism in some cells, such as equine dermis (ED) cells, but not in others, such as equine endothelial cells. EIAVvMA-1c superinfection of ED cells results in a buildup of unintegrated viral DNA and rapid killing of the cell monolayer. Here, we examined the mechanism of resistance that is used by EIAV to prevent superinfection and explored the means by which EIAVvMA-1c overcomes this restriction. We found that the cellular receptor used by EIAV, equine lentivirus receptor 1 (ELR1), remains on the surface of cells chronically infected with EIAV, suggesting that wild-type EIAV interferes with superinfection by masking ELR1. The addition of soluble wild-type SU protein to the medium during infection blocked infection by wild-type strains of virus, implicating SU as the viral protein responsible for interfering with virion entry into previously infected cells. Additionally, interference of wild-type EIAV binding to ELR1 by the addition of either anti-ELR1 antibodies or the ELR1 ectodomain prevented entry of the wild-type strains of EIAV into two permissive cell populations. Many of these same interference treatments prevented EIAVvMA-1c infection of endothelial cells but only modestly affected the ability of EIAVvMA-1c to enter and kill previously infected ED cells. These findings indicate that EIAVvMA-1c retains the ability to use ELR1 for entry and suggest that this virus can interact with an additional, unidentified receptor to superinfect ED cells.

scholarly journals Structural Basis for Accommodation of Emerging B.1.351 and B.1.1.7 Variants by Two Potent SARS-CoV-2 Neutralizing Antibodies

2021 ◽  
Author(s):  
Gabriele Cerutti ◽  
Micah Rapp ◽  
Yicheng Guo ◽  
Fabiana Bahna ◽  
Jude Bimela ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Structural Basis ◽  
Wild Type Virus ◽  
Receptor Binding Domain ◽  
Type Virus ◽  
Wild Type ◽  
Distinct Mechanism ◽  
The Uk

SummaryEmerging SARS-CoV-2 strains, B.1.1.7 and B.1.351, from the UK and South Africa, respectively show decreased neutralization by monoclonal antibodies and convalescent or vaccinee sera raised against the original wild-type virus, and are thus of clinical concern. However, the neutralization potency of two antibodies, 1-57 and 2-7, which target the receptor-binding domain (RBD) of spike, was unaffected by these emerging strains. Here, we report cryo-EM structures of 1-57 and 2-7 in complex with spike, revealing each of these antibodies to utilize a distinct mechanism to bypass or accommodate RBD mutations. Notably, each antibody represented a response with recognition distinct from those of frequent antibody classes. Moreover, many epitope residues recognized by 1-57 and 2-7 were outside hotspots of evolutionary pressure for both ACE2 binding and neutralizing antibody escape. We suggest the therapeutic use of antibodies like 1-57 and 2-7, which target less prevalent epitopes, could ameliorate issues of monoclonal antibody escape.

scholarly journals Vaccination with SARS-CoV-2 variants of concern protects mice from challenge with wild-type virus

PLoS Biology ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. e3001384
Author(s):  
Fatima Amanat ◽  
Shirin Strohmeier ◽  
Philip Meade ◽  
Nicholas Dambrauskas ◽  
Barbara Mühlemann ◽  
...  
Keyword(s):  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Fold Reduction ◽  
Reactive Antibody

Vaccines against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) have been highly efficient in protecting against Coronavirus Disease 2019 (COVID-19). However, the emergence of viral variants that are more transmissible and, in some cases, escape from neutralizing antibody responses has raised concerns. Here, we evaluated recombinant protein spike antigens derived from wild-type SARS-CoV-2 and from variants B.1.1.7, B.1.351, and P.1 for their immunogenicity and protective effect in vivo against challenge with wild-type SARS-CoV-2 in the mouse model. All proteins induced high neutralizing antibodies against the respective viruses but also induced high cross-neutralizing antibody responses. The decline in neutralizing titers between variants was moderate, with B.1.1.7-vaccinated animals having a maximum fold reduction of 4.8 against B.1.351 virus. P.1 induced the most cross-reactive antibody responses but was also the least immunogenic in terms of homologous neutralization titers. However, all antigens protected from challenge with wild-type SARS-CoV-2 in a mouse model.

scholarly journals Selection of a Rare Neutralization-Resistant Variant following Passive Transfer of Convalescent Immune Plasma in Equine Infectious Anemia Virus-Challenged SCID Horses

2010 ◽  
Vol 84 (13) ◽  
pp. 6536-6548 ◽  
Author(s):  
Sandra D. Taylor ◽  
Steven R. Leib ◽  
Susan Carpenter ◽  
Robert H. Mealey
Keyword(s):  
Neutralizing Antibodies ◽  
Equine Infectious Anemia Virus ◽  
Severe Combined Immunodeficiency ◽  
Febrile Episode ◽  
Clinical Disease ◽  
Resistant Variant ◽  
Homologous Virus ◽  
Equine Infectious Anemia ◽  
Anemia Virus

ABSTRACT Vaccines preventing HIV-1 infection will likely elicit antibodies that neutralize diverse strains. However, the capacity for lentiviruses to escape broadly neutralizing antibodies (NAbs) is not completely understood, nor is it known whether NAbs alone can control heterologous infection. Here, we determined that convalescent immune plasma from a horse persistently infected with equine infectious anemia virus (EIAV) neutralized homologous virus and several envelope variants containing heterologous principal neutralizing domains (PND). Plasma was infused into young horses (foals) affected with severe combined immunodeficiency (SCID), followed by challenge with a homologous EIAV stock. Treated SCID foals were protected against clinical disease, with complete prevention of infection occurring in one foal. In three SCID foals, a novel neutralization-resistant variant arose that was found to preexist at a low frequency in the challenge inoculum. In contrast, SCID foals infused with nonimmune plasma developed acute disease associated with high levels of the predominant challenge virus. Following transfer to an immunocompetent horse, the neutralization-resistant variant induced a single febrile episode and was subsequently controlled in the absence of type-specific NAb. Long-term control was associated with the presence of cytotoxic T lymphocytes (CTL). Our results demonstrate that immune plasma with neutralizing activity against heterologous PND variants can prevent lentivirus infection and clinical disease in the complete absence of T cells. Importantly, however, rare neutralization-resistant envelope variants can replicate in vivo under relatively broad selection pressure, highlighting the need for protective lentivirus vaccines to elicit NAb responses with increased breadth and potency and/or CTL that target conserved epitopes.

scholarly journals Suppression of Megakaryocyte Colony Growth by Plasma From Foals Infected With Equine Infectious Anemia Virus

Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2357-2363 ◽  
Author(s):  
Susan J. Tornquist ◽  
Timothy B. Crawford
Keyword(s):  
Neutralizing Antibodies ◽  
Equine Infectious Anemia Virus ◽  
Transforming Growth Factor ◽  
Bone Marrow Cells ◽  
Transforming Growth Factor Β ◽  
Colony Growth ◽  
Tnf Α ◽  
Equine Infectious Anemia ◽  
Anemia Virus

Abstract Foals infected with equine infectious anemia virus become thrombocytopenic 7 to 20 days after virus inoculation, and within a few days following the onset of detectable viremia. The thrombocytopenia is associated with suppression of platelet production. Possible mediators of suppression of thrombopoiesis include tumor necrosis factor-α (TNF-α) and transforming growth factor-β (TGF-β), cytokines that are released during inflammation. To assess effects of plasma or serum from infected foals on megakaryocyte (MK) growth and maturation in vitro, equine low-density bone marrow cells were cultured for clonogenic and ploidy assays. Neutralizing antibodies to TNF-α and TGF-β were added to cultures to determine the contribution of these cytokines to suppression of thrombopoiesis. Plasma from the immediately pre-thrombocytopenia (Pre-Tp) period significantly reduced MK colony numbers. This suppression was partially reversed upon antibody neutralization of plasma TNF-α, TGF-β, or both. There were no differences in ploidy distribution of MK grown in the presence of preinfection serum compared with those grown in the presence of Pre-Tp serum. These results indicate that TNF-α and TGF-β may contribute to suppression of MK proliferation and represent likely factors in the pathogenesis of thrombocytopenia.

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