Immunological responses to emerging phlebo- and arenaviruses

Lead Research Organisation: University of Oxford
Department Name: Structural Biology

Abstract

Emerging New World arena- and phlebo-viruses are threats to human health for which there are no preventative vaccines or therapeutic treatments. Upon infection of a previously unexposed human host, such pathogens often cause rapid disease progression and result in high mortality rates. The viral glycoproteins displayed on the surface of these viruses are the primary determinants of the host immune response and thus lead targets in antiviral and vaccine design. The objective of this work is to study the antibody response against these viral glycoproteins, at a molecular level, with the aim of isolating and characterizing monoclonal antibodies that can target and prevent the virus infection cycle. A particular emphasis of this work is to isolate monoclonal antibodies, which can bind and (cross)-neutralise several biomedically important viruses from the same families. Following isolation of monoclonal antibodies, we will apply X-ray crystallography and other biophysical tools to define neutralising epitopes targeted on the virus surface. By analogy to the success in development of monoclonal antibody cocktails to treat Ebola virus infection, the data and reagents produced in this work will provide a platform by which to therapeutically target these dangerous groups of pathogens.

Technical Summary

Emerging New World arena- and phlebo-viruses are responsible for severe hemorrhagic fever in humans with up to 70% fatality rates in as little as 7-10 days. Here, we will study the humoral immune response against these two groups of viruses through the generation of a library of antibodies capable of cross-neutralising several genetically distinct New World arena-viral and phlebo-viral lineages. We will immunise mice with the antigenic glycoprotein-subcomponents of these viruses and apply a prime-boost strategy with glycoproteins from several related virus species to elicit cross-binding monoclonal antibodies. Following elicitation of a robust immune response, we will employ techniques in antigen-specific single B-cell isolation and molecular biology to isolate two sets of monoclonal antibody libraries, one specific to discreet arenviruses and the other to phleboviruses. Following confirmation of neutralisation activity, the conserved viral epitopes targeted by these neutralising antibodies (nAbs) and the mechanism of neutralisation will be studied at a molecular level using, X-ray crystallography. The nAbs produced will be valuable reagents, useful in the serological detection of emerging New World arena- and phlebo-viruses isolated in the field and also as potential antiviral therapeutic reagents. These structural data revealed from this work will reveal sites of vulnerability on New World arena- and phlebovirus surfaces and neutralising epitopes conserved across distant viral species that could be exploited for antiviral and vaccine design.

Planned Impact

Phleboviruses and New World arenaviruses are causative agents of severe hemorrhagic fever. One of the principal reasons that these viruses exhibit such high mortality rates in humans is that disease progression is often too rapid (7-10 d) for an effective immune response. The risk that these two groups of viruses pose to human health is compounded by a paucity of approved vaccines and specific antiviral treatments. The work proposed here aims to produce neutralising antibodies against these pathogens and to address two basic and one translational biomedical questions:

(1) What is the molecular mechanism of virus neutralisation by the humoral immune response?
(2) Are neutralising epitopes present on viral glycoproteins conserved across distinct species?
(3) And ultimately, can cross-neutralising monoclonal antibodies be generated that can be used in antiviral therapies and treatments?

This project was conceived as a basic biomedical approach to understand how host cell entry and infection pathways of emerging viruses are targeted by the immune response. By addressing these specific questions about virus pathobiology, we will not only have a greater appreciation of host cell entry but also deliver molecular-level templates for the inhibition of these processes. Answering these questions and creating novel antibody reagents will: (i) have an impact upon human health in endemic regions, (ii) enhance readiness for potential bio-weapon threats, and (iii) deliver a general strategy that can be adopted for monoclonal antibody development against a range of biomedically important viruses. Details of these impacts are summarized below:

(i) Human health in endemic areas. New World arenaviruses and phleboviruses are prevalent throughout the World and can emerge from host reservoirs, causing harm to humans without warning. As an extension of our ongoing collaboration with the Public Health England Virology and Pathogenesis research group at Porton Down, the antibody and viral glycoprotein reagents produced in this project may be utilized as tools for serological detection of emerging New World arena- and phlebo-viruses. Thus, mid-term beneficiaries for this research include governmental organizations in the area of viral surveillance and detection.

Furthermore, understanding of neutralising epitopes on the viral surface is key for identifying regions that can be targeted in antiviral and vaccine design. As a long-term beneficiary (e.g. commercial), the antibody reagents produced in this work will likely act as antiviral scaffolds and we anticipate being able to use our structural analysis to propose synergetic antibody combinations, that may be used in antibody cocktail formulation. This work application would be analogous to ongoing development of antiviral cocktails to treat Ebola virus infection (e.g. ZMappTM).

(ii) Readiness to face bio-weapon threats. These viruses, especially New World arenaviruses (which form aerosols), pose to national and international security. The development of antibody antivirals would significantly enhance the capability of the UK to respond rapidly to disease outbreaks. The production of cross-neutralising antibody cocktails targeting conserved epitopes would even further increase national preparedness, as these would constitute broad-spectrum antivirals, which may be used to treat a range of species of New World arenavirus or phlebovirus infection.

(iii) New strategies for monoclonal antibody isolation. Monoclonal antibodies that bind to specific proteins and glycoproteins are essential in many aspects of biomedical research. Hybridoma technologies are typically used however this methodology is not suitable for antibodies that are anticipated to be rare. Optimization of the antigen-specific B cell sorting methodology may enable other researchers to efficiently isolate monoclonal antibodies that are of biomedical interest but likely to be of low abundance.

Publications

10 25 50
 
Description A vaccine for Junín virus
Amount £18,106,014 (GBP)
Funding ID HNR03250 
Organisation Coalition for Epidemic Preparedness Innovations 
Sector Learned Society
Country Norway
Start 09/2023 
End 09/2026
 
Description Molecular-level mapping of the human antibody response to hantavirus infection
Amount £963,964 (GBP)
Organisation Medical Research Council (MRC) 
Sector Public
Country United Kingdom
Start 12/2021 
End 11/2024
 
Description The Language of Zoonosis: Rationalising Receptor-Mediated Spillover of Viral Pathogens at a Molecular Level
Amount £2,252,705 (GBP)
Funding ID MR/S007555/1 
Organisation Medical Research Council (MRC) 
Sector Public
Country United Kingdom
Start 07/2019 
End 07/2024
 
Description A collaboration between Dr Katie Doores (KCL), Prof. Roger Hewson (PHE), and Prof. Thomas Bowden 
Organisation Public Health England
Country United Kingdom 
Sector Public 
PI Contribution This collaboration encompasses the MRC project grant. My group performs the biophysical and structural biology work.
Collaborator Contribution Dr Katie Doores (and group) performs antibody isolation and characterisation work. Prof. Roger Hewson (and group) tests antibody efficacy.
Impact This collaboration has resulted in a key publication related to the project (PMID 30590046), and involved immunology, structural biology, and in vitro analysis.
Start Year 2015
 
Description HPRU 
Organisation Public Health England
Department Public Health England Porton Down
Country United Kingdom 
Sector Public 
PI Contribution I am a member of the Health Protection Research Unit member, Zoonotic Infections (co-lead of Pathogen and Vector Biology Theme).
Collaborator Contribution This is a newly developed consortium, where I will provide structural virology expertise and broaden existing collaborations with groups (i.e. Drs Hewson and Dowell) at Public Health England.
Impact This consortium recently started and there are no outcomes yet.
Start Year 2020
 
Description In2science 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact My lab hosted a sixth-form student for 2 weeks through the in2science programme. This programme aims to expose children from disadvantaged schools to a university and research setting and to equip them in their application to university.
Year(s) Of Engagement Activity 2018
 
Description In2science 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact I hosted 1 student in my lab for 1 week as part of the in2science scheme.
Year(s) Of Engagement Activity 2019
 
Description School visit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I spoke to year 12 and 13 students doing biology A-level about my research relating to infection and immunity. They had studied the basics of the topic in their lessons and we discussed how research can aid in vaccine development against infectious diseases.
Year(s) Of Engagement Activity 2020
 
Description School visit 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I visited a local primary school as part of their science week activities. I did a talk about what it was like to be a scientisit and what we actually do. The children were able to ask questions too.
Year(s) Of Engagement Activity 2018