Intracellular-delivery of a single-chain antibody against hepatitis B core protein via cell-penetrating peptide inhibits hepatitis B virus replication in vitro

Abstract

Assembly of nucleocapsids is an attractive target for novel anti-hepatitis B virus (HBV) agents, and intracellular single-chain variable fragment (scFv) antibodies against HBV core (HBc) protein are a class of potential alternatives for this purpose; however, their application is limited by the lack of a suitable means of delivery. Owing to the favorable performance of cytoplasmic transduction peptide (CTP) in cargo delivery in hepatocytes, we purified an anti-HBc scFv fused to CTP using a previous screened sequence by a prokaryotic expression system and evaluated its efficacy in the inhibition of HBV in vitro. Our results showed that cytoplasmic translocation of the previous anti-HBc scFv was achieved by CTP in HepG2.2.15 cells. Immunoprecipitation analysis indicated the fusion protein anti-HBc scFv-CTP interacted with its target antigen HBc, and negligible cytotoxicity was observed. Moreover, the anti-HBc scFv-CTP interfered with nucleocapsid assembly and markedly reduced both the supernatant HBV DNA level and the intracellular DNA replication intermediates, with a 5.1 µM of half maximal effect concentration and a dose-dependent effect. In conclusion, this novel anti-HBc scFv fused to CTP demonstrated inhibitory activity of HBV replication in vitro and warrants further in vivo study.

A monoclonal antibody binds to threonine 49 in the non-structural 1 protein of influenza A virus and interferes with its ability to modulate viral replication

“…Moreover, cytoplasmic transduction peptide (CTP), a stretch of basic residues, has been extensively documented for its efficient delivery of biomolecules (Gump and Dowdy, 2007;Kim et al, 2006). Recently, hepatitis B virus replication has been reported to be inhibited by intracellular delivery of scFv against core protein via CTP (Xun et al, 2013). As an alternative to viral expression vectors, 2H6-scFv can be fused with CTP for the efficient cytoplasmic translocation of the scFv into the cells.…”

The Protective Effect of a Combination of Human Intracellular and Extracellular Antibodies against Highly Pathogenic Avian Influenza H5N1 Virus

“…In addition, intrabody scFvs possess several advantages over full-length IgG: a simple and compact structure, higher stability, and increased solubility. Intrabodies based on scFvs have already been developed against human immunodeficiency virus-1 [25], hepatitis B virus [26], hepatitis C virus [27], rotavirus [28], herpes virus [28,29] and influenza virus [30]. The intrabody-based strategy can be applied to the development of future therapeutic agents against viruses because the cytoplasm is one of the most important environments for viral replication and amplification.…”

Neutralizing human recombinant antibodies against herpes simplex virus type 1 glycoproteins B from a phage-displayed scFv antibody library

“…Owing to their several advantages, single chain antibodies could serve as useful tools for antibody-based therapies. Better penetration to target tissues because of the small size [16,40] has made scFvs more effective than antibodies in therapeutic applications especially when viral antigens are the targets [41,42].…”