Bovine single chain Fv antibody inhibits bovine herpesvirus-1 infectivity by targeting viral glycoprotein D

Abstract

Glycoprotein D (gD) of bovine herpesvirus-1 (BoHV-1) is essential for attachment and penetration of cells during infection and is a major target for neutralizing antibodies during an adaptive immune response. Currently there are no recombinant antibodies capable of binding gD epitopes for use in treating BoHV-1 infection. In this study, a bovine scFv gene derived from a hybridoma secreting monoclonal antibodies (McAbs) against the amino acid motif MEESKGYEPP of gD was expressed in E. coli. Molecular modeling, western blot and ELISA analysis showed that this scFv had a high affinity for BoHV-1 gD, with a Kd of 161.2 ± 37.58 nM and for whole BoHV-1 virus, with a Kd of 67.44 ± 16.99 nM. In addition, this scFv displayed a high affinity for BoHV-1 antigen in an ELISA and competed with BoHV-1 anti-serum in a competitive ELISA. Immunofluorescence assay (IFA) and laser confocal microscopy showed that this scFv could efficiently bind to and be internalized by BoHV-1 infected Madin-Darby bovine kidney (MDBK) cells. Importantly, this scFv was shown to inhibit BoHV-1 infectivity and to reduce the number of viral plaques by blocking viral attachment to MDBK cells. Our study suggests that this bovine single-chain antibody could be developed for use as a diagnostic and therapeutic agent against BoHV-1 infection in cattle.

Antiviral Immunotoxin Against Bovine herpesvirus-1: Targeted Inhibition of Viral Replication and Apoptosis of Infected Cell

“…The results clearly demonstrated the inhibitory activity of BoScFv-PE38 immunotoxin for BoHV-1. Considering the neutralization activity of scFv in our previous study ( Xu et al, 2017 ), the use of antibody portion scFv within BoScFv-PE38 immunotoxin could also target cell free virions during cytolytic phase of BoHV-1 infection in cattle. We therefore, conclude that our developed BoScFv-PE38 immunotoxin had an ability to target BoHV-1 at lytic phases of infection.…”

“…The protein sequence of Pseudomonas exotoxin A (PE38) was downloaded from the NCBI database 1 ; sequences of a truncated version of PE38, the BoHV-1 ScFv protein and the linker peptide are obtained according to our earlier study ( Xu et al, 2017 ), which were listed in Supplementary Table S1 . The domains of BoScFv-PE38 were analyzed using the PROSITE database 2 .…”

“…In our previous study, we demonstrated that scFv targeting of viral glycoprotein D (gD) inhibited the infectivity of BoHV-1 in Madin-Darby bovine kidney (MDBK) cells ( Xu et al, 2017 ). In the present study, we developed BoHV-1-specific scFv that acted as the targeting molecule.…”

Mapping a highly conserved linear neutralizing epitope on gD glycoprotein of bovine herpesvirus type I using a monoclonal antibody

“…To date, at least 12 envelope glycoproteins of BoHV-1 have been identified [13], of which the major envelope glycoproteins, glycoprotein B (gB), glycoprotein C (gC), glycoprotein D (gD), induce protective immune response from diseases and are also the targets of protective host immune response [3, 34, 38]. Compared with gB and gC glycoproteins, gD may induce more robust immune responses, enabling the protection against BoHV-1 challenge [12, 33, 37, 39]. Additionally, gD plays a key role in viral attachment and penetration into the permissive cells [7, 13, 25].…”