Defective humoral responses and intravascular apoptosis in fatal EBOV infection

Nat Med. 1999 Apr;5(4):423-6. Defective humoral responses and extensive intravascular apoptosis are associated with fatal outcome in Ebola virus-infected patients.

Baize S¹, Leroy EM, Georges-Courbot MC, Capron M, Lansoud-Soukate J, Debré P, Fisher-Hoch SP, McCormick JB, Georges AJ.

Author information

Abstract

Ebola virus is very pathogenic in humans. It induces an acute hemorrhagic fever that leads to death in about 70% of patients. We compared the immune responses of patients who died from Ebola virus disease with those who survived during two large outbreaks in 1996 in Gabon.

 In survivors, early and increasing levels of IgG, directed mainly against the nucleoprotein (NP)  and the 40-kDa viral protein (VP40) , were followed by clearance of circulating viral antigen and activation of cytotoxic T cells, which was indicated by the upregulation of FasL, perforin, CD28 and gamma interferon mRNA in peripheral blood mononuclear cells.

 In contrast, fatal infection was characterized by impaired humoral responses, with absent specific IgG and barely detectable IgM.
  Early activation of T cells, indicated by mRNA patterns in peripheral blood mononuclear cells and considerable release of gamma interferon in plasma, was followed in the days preceding death by the disappearance of T cell-related mRNA (including CD3 and CD8).  
DNA fragmentation in blood leukocytes and release of 41/7 nuclear matrix protein in plasma indicated that massive intravascular apoptosis proceeded relentlessly during the last 5 days of life.

Thus, events very early in Ebola virus infection determine the control of viral replication and recovery or catastrophic illness and death.

Comment in

Surviving Ebola virus infection. [Nat Med. 1999]

ZMABb, EBOV specific monoclonal antibodies to NHP : Sustained protection against EBOV . VSVΔG/ZEBOVGP vaccine

Scientific Reports | Article Open

 VSVΔG/ZEBOVGP vaccine

Results: 4

Select item 219259511.

Characterization of Zaire ebolavirus glycoprotein-specific monoclonal antibodies.

Qiu X, Alimonti JB, Melito PL, Fernando L, Ströher U, Jones SM.

Clin Immunol. 2011 Nov;141(2):218-27. doi: 10.1016/j.clim.2011.08.008. Epub 2011 Aug 31.

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Select item 194402452.

Mucosal immunization of cynomolgus macaques with the VSVDeltaG/ZEBOVGP vaccine stimulates strong ebola GP-specific immune responses.

Qiu X, Fernando L, Alimonti JB, Melito PL, Feldmann F, Dick D, Ströher U, Feldmann H, Jones SM.

PLoS One. 2009;4(5):e5547. doi: 10.1371/journal.pone.0005547. Epub 2009 May 14.

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Single-injection vaccine protects nonhuman primates against infection with marburg virus and three species of ebola virus.

Geisbert TW, Geisbert JB, Leung A, Daddario-DiCaprio KM, Hensley LE, Grolla A, Feldmann H.

J Virol. 2009 Jul;83(14):7296-304. doi: 10.1128/JVI.00561-09. Epub 2009 Apr 22.

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Vesicular stomatitis virus-based ebola vaccine is well-tolerated and protects immunocompromised nonhuman primates.

Geisbert TW, Daddario-Dicaprio KM, Lewis MG, Geisbert JB, Grolla A, Leung A, Paragas J, Matthias L, Smith MA, Jones SM, Hensley LE, Feldmann H, Jahrling PB.

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Sustained protection against Ebola virus infection following treatment of infected nonhuman primates (NHP)  with ZMAb

Xiangguo Qiu,et al.

Scientific Reports3, Article number:3365
doi:10.1038/srep03365 Received 11 September 2012 Accepted 12 November 2013
Published 28 November 2013 

Ebola virus (EBOV) is one of the most lethal filoviruses, with mortality rates of up to 90% in humans. Previously, we demonstrated 100% and 50% survival of EBOV-infected cynomologus macaques with a combination of 3 EBOV-GP-specific monoclonal antibodies (ZMAb) administered at 24 or 48 hours post-exposure, respectively.
The survivors demonstrated EBOV-GP–specific humoral and cell-mediated immune responses. In order to evaluate whether the immune response induced in NHPs during the ZMAb treatment and EBOV challenge is sufficient to protect survivors against a subsequent exposure, animals that survived the initial challenge were rechallenged at 10 or 13 weeks after the initial challenge.
 The animals rechallenged at 10 weeks all survived whereas 4 of 6 animals survived a rechallenge at 13 weeks. The data indicate that a robust immune response was generated during the successful treatment of EBOV-infected NHPs with EBOV, which resulted in sustained protection against a second lethal exposure.

Introduction

(Oma kommentti 26.10.2014  Käyttääkö EBV myös kuten influenssavirus  samanlaista antigeenivispilää, jossa sikakarja toimii yhtenä  väli-isäntä ennen ihmiskuntaan paremmin sopeutumista? Siinä tapauksessa EBOV omaa  kuuman pandemisen potentiaalin koska on nyt Kauko-Aasiassa tavattu sikakarjasta RESTON virus muotoisena.   Periaatteessa siis olisi odotettavissa hieman  uusimuotoinen ebolaviruspandemia  joidenkin vuosien, tai  vuosikymmenien päästä, joten rokotekehittelyllä on todellinen kiire).

Ebola virus is a member of the family Filoviridae¹. It causes severe hemorrhagic fevers in primates and respiratory disease in pigs². 

 Of the five Ebolavirus species, Zaire ebolavirus (EBOV) is the most lethal in humans, with a mortality rate approaching 90%. While EBOV is not currently a major burden on public health, the lack of an approved vaccine and post-exposure treatment raises concerns in the event of a possible outbreak. Several vaccines (reviewed in Falzarano et al.³), and post-exposure therapeutics have been developed with mixed success⁴. Many promising vaccines are moving through pre-clinical or clinical trials, but mass immunization is unlikely due to the localized and sporadic nature of EBOV infections.
 Post-exposure interventions are therefore necessary for the treatment of cases as they occur, but have been harder to develop as death from an EBOV infection typically occurs within 6–9 days in non-human primates (NHPs)^{5, 6}.
 This leaves a very short window for the treatment to reduce virus replication until the immune response expands sufficiently to control the infection.

Currently, the majority of proposed post-exposure therapeutics needs to be administered within one hour in order to fully protect experimentally infected animals^{6, 7, 8}.

The initial treatments evaluated against EBOV were more supportive in nature with a focus on remediating the coagulation abnormalities induced by the virus^{9, 10, 11, 12, 13}.

(Kommentti: Viruksen suhteellisen pieni genomi ei sisällä mitään tekijää, joka ei olisi vitaalin tärkeä, vaikka primääri virionin kehittely toimisi  harvemmilla geeneillä kuin  systeemiset vaikutukset, mutta sekundäärinen koagulatiohäiriö  edistää taas viruksen hyvää laiduntamista ja invasoitumista  ja todennäköisesti  aiheutuu  VLP lehteilystä-. Jotkut virukset kuten influenssavirus hyötyvät isäntäkehon pysymisestä hengissä, mutta  ebolalavirukselle  on hyötyä isäntäkehon  solutuotyeiden kuten kalvolipidien kehityymisestä vain hyvin retriktiivisesti,   joten  virionien  valmistuttua  kehon kuolema on eduksi virionin  invasoitumiselle ja leviämiselle . kasvumiljööaineena.  Tämän takia  antivirusvaste ja virionin  esiinsilmukoitumisen  häiritseminen  pitäisi saada vireille ennen päivää 21. Tässä voisi käyttää jotain epäsuoraa keinoa. T- solujen  aktivoimiseksi.  Ehkä yleinen rokotusohelma olisi hyväksi, en tiedä.  Ebolan tyrmäävän evaasiostrategian heikkojen kohtien tarkka tunteminen on hyväksi.).

A study using the VSVΔG/ZEBOVGP vaccine as a post-exposure intervention showed that this strategy was more efficacious than previous interventions, protecting 50% of the infected animals if administered within 30 minutes after exposure⁶.

More recently, antisense therapy has been applied to EBOV infection with success.
 Modified phosphorodiamidate morpholino oligomers (PMOplus) were found to protect 62.5% of the infected animals when administered daily for 10–14 days⁸.

 Small interfering RNAs (siRNAs)   were shown to be fully protective in NHPs when administered daily for seven days⁷. In both cases, treatment began within 30–60 minutes of exposure.

Passive immunization constitutes another strategy to treat EBOV infections and was first attempted during the initial outbreak in 1976, where an infected laboratory employee was successfully treated with interferon and convalescent serum¹⁴.

 During the 1995 outbreak, convalescent serum was administered to eight infected individuals, seven of which survived¹⁵. However, evaluations of passive therapies in animal models have had mixed success.

The administration of immunoglobulin G (IgG) purified from EBOV-hypervaccinated horses failed to protect macaques against an EBOV challenge^{16, 17} and the neutralizing human monoclonal antibody KZ52, isolated from a survivor of EBOV infection, also failed to protect macaques¹⁸.

 However, polyclonal IgG from rhesus macaques which survived an EBOV challenge was shown to protect naïve rhesus macaques when administered up to 48 hours after infection¹⁹.

In 2012, two groups demonstrated partial protection in rhesus macaques following treatment with monoclonal antibodies at 24 hours after infection^{20, 21} and one group reported complete protection in cynomolgus macaques with another monoclonal antibody treatment (ZMAb) also initiated 24 hours after infection²². In addition, the ZMAb treatment protected two of four macaques when initiated 48 hours after exposure.

 In 2013, the treatment window was extended by using an adenovirus-vectored consensus human IFNα (Ad-IFN)²³ administered with or before ZMAb²⁴. While the precise mechanism of protection remains unclear, it was shown that the monoclonal antibody-based treatment did not completely inhibit EBOV replication, leading to the development of a host immune response against EBOV^{22, 24}.

In order to evaluate whether the immune response induced in NHPs during the ZMAb treatment and EBOV challenge is of sufficient quality to protect survivors against a subsequent exposure, ZMAb-treated animals that survived an initial challenge^{22, 24} were rechallenged with EBOV either 10 or 13 weeks after the initial challenge and the memory immune responses were evaluated before and during the rechallenge.

EBOV and B-cells (B-lymphocytes). Humoral immunity and Immunoglobulin profile

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0096360

Research Article

Identification of Continuous Human B-Cell Epitopes in the VP35, VP40, Nucleoprotein and Glycoprotein of Ebola Virus

• Pierre Becquart et al.

• Published: June 10, 2014
• DOI: 10.1371/journal.pone.0096360

Abstract

Ebola virus (EBOV) is a highly virulent human pathogen. Recovery of infected patients is associated with efficient EBOV-specific immunoglobulin G (IgG) responses, whereas fatal outcome is associated with defective humoral immunity.

As B-cell epitopes on EBOV are poorly defined, we sought to identify specific epitopes in four EBOV proteins (Glycoprotein (GP), Nucleoprotein (NP), and matrix Viral Protein (VP)40 and VP35).

 For the first time, we tested EBOV IgG+ sera from asymptomatic individuals and symptomatic Gabonese survivors, collected during the early humoral response (seven days after the end of symptoms) and the late memory phase (7–12 years post-infection).

We also tested sera from EBOV-seropositive patients who had never had clinical signs of hemorrhagic fever or who lived in non-epidemic areas (asymptomatic subjects).

 We found that serum from asymptomatic individuals was more strongly reactive to VP40 peptides than to GP, NP or VP35.

 Interestingly, anti-EBOV IgG from asymptomatic patients targeted three immunodominant regions of VP40 reported to play a crucial role in virus assembly and budding.

 In contrast, serum from most survivors of the three outbreaks, collected a few days after the end of symptoms, reacted mainly with GP peptides.

However, in asymptomatic subjects the longest immunodominant domains were identified in GP, and analysis of the GP crystal structure revealed that these domains covered a larger surface area of the chalice bowl formed by three GP₁ subunits.

The B-cell epitopes we identified in the EBOV VP35, VP40, NP and GP proteins may represent important tools for understanding the humoral response to this virus and for developing new antibody-based therapeutics or detection methods.