Human transbodies that interfere with the functions of Ebola virus VP35 protein in genome replication and transcription and innate immune antagonism

Abstract

Small molecular inhibitors and passive immunization against Ebola virus disease (EVD) have been tested in animal models, including rodents and non-human primates, as well as in clinical trials. Nevertheless, there is currently no Food and Drug Administration (FDA)-approved therapy, and alternative strategies must be pursued. The aim of this study was to produce cell-penetrable human single-chain antibodies (transbodies) that are able to interfere with the activities of interferon inhibitory domain (IID) of the VP35 protein, a multifunctional virulence factor of Ebola virus (EBOV). We speculated that effective VP35-IID-specific transbodies could inspire further studies to identify an alternative to conventional antibody therapies. Phage display technology was used to generate Escherichia coli-derived human single-chain antibodies (HuscFvs) that bind to IID. HuscFvs were linked to nona-arginine (R9) to make them cell penetrable. Transbodies of transformed E. coli clones 13 and 3, which were predicted to interact with first basic patch residues (R9-HuscFv13), central basic patch, and end-cap residues (R9-HuscFv3), effectively inhibited EBOV minigenome activity. Transbodies of E. coli clones 3 and 8 antagonized VP35-mediated interferon suppression in VP35-transduced cells. We postulate that these transbodies formed an interface contact with the IID central basic patch, end-cap, and/or residues that are important for IID multimeric formation for dsRNA binding. These transbodies should be evaluated further in vitro using authentic EBOV and in vivo in animal models of EVD before their therapeutic/prophylactic effectiveness is clinically evaluated.

COVID-19, an emerging coronavirus infection: advances and prospects in designing and developing vaccines, immunotherapeutics, and therapeutics

“…Examples include trans bodies to influenza virus, hepatitis C virus, Ebola virus, and Dengue virus. 41 Thus, it is possible to generate trans bodies to CoV intracellular proteins such as the papain-like proteases (PLpro), cysteine-like protease (3CLpro) or other non-structural proteins (nsps) that are pivotal for CoV replication and transcription for safe, nonimmunogenic, broadly effective passive immunization of CoVexposed subjects and treatment of infected patients.…”

Insights into Ebola Virus VP35 and VP24 Interferon Inhibitory Functions and their Initial Exploitation as Drug Targets

“…Although the increasing and constant effort in the identification of VP35 and VP24 inhibitors and despite recent progresses have been made in developing novel techniques to test their functions, nowadays no approved drugs are available against these promising pharmacological targets. These studies involved in vitro, in vivo and in silico approaches aimed to identify potential inhibitors among small molecules and FDA-approved drugs, plant extracts or compounds, oligomers, peptides and immune therapies [16,18,19,63,[102][103][104][105][106][107][108][109][110][111][112][113] Figure 5. VP35 and VP24 inhibitors.…”

“…Cellpenetrating peptides (CPPs) were developed to the aim of facilitating the entry of active compounds into cells, thanks to the electrostatic interactions between their positive charge and the negatively charge of membrane components [137,138]. Seesuay et al used as CPP the nona-arginine (R9) to mediate the transport of human single chain variable antibodies fragments (HuscFvs) or tranbodies directed against VP35 that specifically recognize the IID function [107]. HepG2 cells transduced with a lentivector carrying VP35 were treated with R9-HuscFv3 and R9-HuscFv8 and gene expression of IFNβ1 promoter and EIF2AK2, encoding for PKR, were evaluated.…”

Coronavirus Disease 2019 – COVID-19

“…Inhibition of virus replication can be achieved by exploiting fully human antibodies (human single-chain antibodies; HuscFvs) or humanized-nanobodies (single-domain antibodies, sdAb, VH/VHH) which can traverse across the membrane of virus-infected cells (transbodies) and could bind to-/interfere with-biological properties of the replicating virus proteins. Like transbodies to the influenza virus, hepatitis C virus, Ebola virus, and Dengue virus (206). Hence generating transbodies directed against CoV intracellular proteins such as papain-like proteases (PLpro), cysteine-like protease (3CLpro) or other non-structural proteins (nsp) that are pivotal for virus replication and transcription, could be a useful approach for safe, broadly effective passive immunization virus exposed subjects and as therapeutics for infected patients.…”