Characterization of the Envelope Glycoprotein of a Novel Filovirus, Lloviu Virus

Abstract

f Lloviu virus (LLOV), a novel filovirus detected in bats, is phylogenetically distinct from viruses in the genera Ebolavirus and Marburgvirus in the family Filoviridae. While filoviruses are known to cause severe hemorrhagic fever in humans and/or nonhuman primates, LLOV is biologically uncharacterized, since infectious LLOV has never been isolated. To examine the properties of LLOV, we characterized its envelope glycoprotein (GP), which likely plays a key role in viral tropism and pathogenicity. We first found that LLOV GP principally has the same primary structure as the other filovirus GPs. Similar to the other filoviruses, virus-like particles (VLPs) produced by transient expression of LLOV GP, matrix protein, and nucleoprotein in 293T cells had densely arrayed GP spikes on a filamentous particle. Mouse antiserum to LLOV VLP was barely cross-reactive to viruses of the other genera, indicating that LLOV is serologically distinct from the other known filoviruses. For functional study of LLOV GP, we utilized a vesicular stomatitis virus (VSV) pseudotype system and found that LLOV GP requires low endosomal pH and cathepsin L, and that human C-type lectins act as attachment factors for LLOV entry into cells. Interestingly, LLOV GP-pseudotyped VSV infected particular bat cell lines more efficiently than viruses bearing other filovirus GPs. These results suggest that LLOV GP mediates cellular entry in a manner similar to that of the other filoviruses while showing preferential tropism for some bat cells.

Chimeric Filoviruses for Identification and Characterization of Monoclonal Antibodies

“…To generate the final full-length constructs, the ApaI-SacI fragments of the generated subclones were transferred to pEBO-eGFP plasmid for substitution of the existing EBOV GP ORF with an ORF encoding the GP of BDBV, SUDV, or MARV or to replace the EBOV GP ectodomain with a MARV GP ectodomain. For the construction of EBOV fulllength clone with its GP replaced by that of LLOV, we first changed editing site in LLOV GP ORF from 8A to 7A (antigenome DNA sense) by mutagenizing pBsII SK (ϩ)-LLOV GP plasmid (provided by Ayato Takada [28]) to make it identical to the original LLOV sequence (6). Also, two existing KpnI restriction endonuclease sites in LLOV GP ORF were knocked down by the introduction of silent mutations.…”

Host Cell Factors Involved in Filovirus Infection

“…1c and 2b). Intriguingly, the furin recognition motif is highly conserved among GPs of all known filoviruses, including the newly found cuevavirus [3,[19][20][21]. However, the biological significance of the furin-mediated GP cleavage remains unknown since the cleavage has been shown to be nonessential for viral replication in vitro and pathogenicity in monkeys [22,23].…”

A review on the Ebola virus, outbreak history and the current research tools to control the disease

“…Zaire ebolavirus is thought to be the most pathogenic, causing up to 90% mortality in infected people. In contrast, Reston ebolavirus, (which is thought to be an Asian species) has never caused a lethal infection in humans and is weak pathogenic virus in experimentally infected nonhuman primates compared with Zaire ebolavirus [21,23]. Three Ebolavirus species (Zaire, Sudan and Bundibugyo) are the main responsible for the Ebola outbreaks in Africa [24][25][26].…”

“…Filoviridae which is the family of Ebola virus [13], was first discovered in 1967, when laboratory workers in Germany and Yugoslavia got a severe hemorrhagic fever as result of exposure to tissues of African green monkeys (Cercopithecus aethiops) imported from Uganda [14][15][16]. At present, this family has three genera: Marburgvirus, Ebolavirus and Cuevavirus [17][18][19][20][21][22]. The genus Ebolavirus consists of five species: Bundibugyo ebolavirus (BDBV), Zaire ebolavirus (EBOV), Reston ebolavirus (RESTV), Sudan ebolavirus (SUDV) and Taï Forest ebolavirus (TAFV) [18][19][20]22,23].…”