Tropical Medicine and Infectious Disease ArticleArticle Cross-NeutralisationCross-Neutralisation of ofNovel Novel Bombali Bombali Virus Virus by by Ebola Ebola Virus Virus Antibodies and Convalescent Plasma Using an Optimised AntibodiesPseudotype-Based and Convalescent Neutralisation Plasma Assay Using an Optimised Pseudotype-Based Neutralisation Assay Emma M. Bentley 1,* , Samuel Richardson 1,†, Mariliza Derveni 2, Pramila Rijal 3, Alain R. Townsend 3, 4 1 2 EmmaJonathan M. Bentley L. Heeney 1,*, Samuel, Giada Richardson Mattiuzzo 1,†, Marilizaand Edward Derveni Wright 2, Pramila Rijal 3, Alain R. Townsend 3, Jonathan L. Heeney 4, Giada Mattiuzzo 1 and Edward Wright 3 1 Division of Virology, National Institute for Biological Standards and Control-MHRA, Blanche Lane, South Mimms EN6 3QG, UK; [email protected] (S.R.); 1 Division of Virology, National Institute for Biological Standards and Control-MHRA, Blanche Lane, [email protected] (G.M.) South Mimms EN6 3QG, UK; [email protected] (S.R.); [email protected] (G.M.) 2 School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; [email protected] (M.D.); 2 School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK; [email protected] [email protected] (E.W.) 3 MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of 3 MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department Medicine, University of Oxford, Oxford OX3 9DS, UK; [email protected] (P.R.); of Medicine, University of Oxford, Oxford OX3 9DS, UK; [email protected] (P.R.); [email protected] (A.R.T.); [email protected] (E.W.) [email protected] (A.R.T.) 4 Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 OES, UK; [email protected] 4 Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 OES, UK; [email protected] * Correspondence: [email protected] * Correspondence: [email protected] † Current Address: The Pirbright Institute, Woking GU24 0NF, UK. † Current Address: The Pirbright Institute, Woking GU24 0NF, UK. Abstract: Ebolaviruses continue to pose a significant outbreak threat, and while Ebola virus (EBOV)- Abstract: Ebolaviruses continue to pose a significant outbreak threat, and while Ebola virus (EBOV)- specific vaccines and antivirals have been licensed, efforts to develop candidates offering broad spe- Citation: Bentley, E.M.; Richardson, specific vaccines and antivirals have been licensed, efforts to develop candidates offering broad cies cross-protection are continuing. The use of pseudotyped virus in place of live virus is recognised S.; Derveni, M.; Rijal, P.; Townsend, species cross-protection are continuing. The use of pseudotyped virus in place of live virus is as an alternative, safer, high-throughput platform to evaluate anti-ebolavirus antibodies towards A.R.; Heeney, J.L.; Mattiuzzo, G.; recognised as an alternative, safer, high-throughput platform to evaluate anti-ebolavirus antibodies their development, yet it requires optimisation. Here, we have shown that the target cell line im- Citation:Wright, Bentley, E. Cross-Neutralisation E.M.; Richardson, of towards their development, yet it requires optimisation. Here, we have shown that the target cell S.; Derveni, M.; Rijal, P.; Townsend, pacts neutralisation assay results and cannot be selected purely based on permissiveness. In ex- Novel Bombali Virus by Ebola Virus line impacts neutralisation assay results and cannot be selected purely based on permissiveness. In A.R.; Heeney,Antibodies J.L.; andMattiuzzo, Convalescent G.; Plasmapanding the platform to incorporate each of the ebolavirus species envelope glycoprotein, allowing expanding the platform to incorporate each of the ebolavirus species envelope glycoprotein, allowing Wright,Using E. Cross-Neutralisation an Optimised Pseudotype- of a comprehensive assessment of cross-neutralisation, we found that the recently discovered Bombali a comprehensive assessment of cross-neutralisation, we found that the recently discovered Bombali Novel BombaliBased Neutralisation Virus by Ebola Assay. VirusTrop. virus has a point mutation in the receptor-binding domain which prevents entry into a hamster cell virus has a point mutation in the receptor-binding domain which prevents entry into a hamster AntibodiesMed. and Infect. Convalescent Dis. 2021, 6 , 155. https://line and, importantly, shows that this virus can be cross-neutralised by EBOV antibodies and con- cell line and, importantly, shows that this virus can be cross-neutralised by EBOV antibodies and Plasmadoi.org/10.3390/tropicalmed6030155 Using an Optimised valescent plasma. Pseudotype-Based Neutralisation convalescent plasma. Assay. AcademicTrop. Med. Editors:Infect. Dis. Abhishek 2021, 6,Pandey Keywords: ebolavirus; pseudotyped virus; cross-neutralisation x. https://doi.org/10.3390/xxxxxand Laura Skirp Keywords: ebolavirus; pseudotyped virus; cross-neutralisation AcademicReceived: Editors: 30 Abhishek July 2021 Pandey and LauraAccepted: Skirp 21 August 2021 Published: 25 August 2021 1. Introduction1. Introduction Received: 30 July 2021 The 2013–2016The 2013–2016 outbreak outbreak of Ebola of Ebola virus virus in West in WestAfrica, Africa, which which was declared was declared a public a public Accepted:Publisher’s 21 August Note: 2021MDPI stays neutralhealthhealth emergency emergency of international of international concern concern (PHEIC) (PHEIC) and caused and caused over over28,000 28,000 cases cases and and Published: 24 August 2021 with regard to jurisdictional claims11,000 in 11,000 deaths deaths [1,2], [1 re-focused,2], re-focused the theworld’s world’s attention attention on on the the public public health health threat thethe EbolavirusEbo- published maps and institutional affil-lavirusgenus genus represents. represents. This This included included the the establishmentestablishment andand inclusion of Ebola Ebola virus virus on on the Publisher’siations. Note: MDPI stays neu- the WorldWorld Health Health Organization’s Organization’s research research an andd development development blueprint blueprint [3], [3], which which priori- prioritizes tral with regard to jurisdictional tizes fundamentalfundamental researchresearch andand supports supports the the development development of of vaccines vaccines and and therapeutics therapeutics along claims in published maps and institu- along with preparedness activities to mitigate future outbreaks. tional affiliations. with preparedness activities to mitigate future outbreaks. The firstThe documented first documented cases casesof viral of haemorrh viral haemorrhagicagic fever caused fever causedby an ebolavirus by an ebolavirus oc- Copyright: © 2021 by the authors.curredoccurred in 1976, in with 1976, nearly with nearlysimultaneous simultaneous outbreaks outbreaks of Ebola of Ebolavirus virus(EBOV) (EBOV) [4] and [4] Sudan and Sudan Licensee MDPI, Basel, Switzerland. virusvirus (SUDV) (SUDV) [5] in [5 ]Central in Central Africa. Africa. Up Up until until 2013, 2013, they they had had each each caused sporadicsporadic outbreaksout- This article is an open access article Copyright: © 2021 by the authors. breakslimited limited to to this this region region [6, 7[6,7]] and and this this trend trend has has continued continued since since the the PHEIC PHEIC with with a further a distributed under the terms and Submitted for possible open access further5 outbreaks 5 outbreaks of of EBOV, EBOV, as as well well as as an an outbreak outbreak in in West West Africa Africa [ 8[8].]. HumanHuman casescases have also conditions of the Creative Commons publication under the terms and con- also occurredoccurred with with two two further further species species identified; identified; these these are are the the Bundibugyo Bundibugyo virus virus (BUDV) (BUDV) and Attribution (CC BY) license (https:// ditions of the Creative Commons At- and thethe Taϊ Forest virus (TAFV).(TAFV). Distinctly,Distinctly, Reston Reston virus virus (RESTV), (RESTV), which which has has been been identified iden- in creativecommons.org/licenses/by/ tribution (CC BY) license (http://crea- tifiedprimate in primate and and swine swine populations populations within within the Philippines, the Philippines, is non-pathogenic is non-pathogenic in humans in hu- [9,10]. 4.0/). tivecommons.org/licenses/by/4.0/). mans [9,10]. In 2018, as part of the PREDICT project to detect known and unknown viruses Trop. Med.Trop. Infect. Med. Infect.Dis. 2021 Dis., 62021, x. https://doi.org/10.3390/xxxxx, 6, 155. https://doi.org/10.3390/tropicalmed6030155 https://www.mdpi.com/journal/tropicalmedwww.mdpi.com/journal/tropicalmed Trop. Med. Infect. Dis. 2021, 6, 155 2 of 12 In 2018, as part of the PREDICT project to detect known and unknown viruses within wildlife reservoirs [11–13], the genome sequence of a further ebolavirus, Bombali virus (BOMV), was isolated from free-tailed bats in Sierra Leone [14]. Subsequent surveys have also found it to be present in bats in Kenya and Guinea [15–17]. Through in situ sequence analysis and the use of a recombinant vesicular stomatitis virus (rVSV) encoding the BOMV glycoprotein (GP), it was determined that entry into human cells occurs via the Niemann– Pick C1 (NPC1) receptor, similar to other ebolaviruses [14]. However, the potential to cause disease in humans remains unknown. Currently, EBOV-specific vaccines and antivirals have been licensed for use following expedited development [18].