Related Experiment Video

Updated: May 29, 2026

Method for Measurement of Viral Fusion Kinetics at the Single Particle Level
14:59

Method for Measurement of Viral Fusion Kinetics at the Single Particle Level

Published on: September 7, 2009

A fusion-loop antibody enhances the infectious properties of immature flavivirus particles

Izabela A Rodenhuis-Zybert1, Bastiaan Moesker, Júlia M da Silva Voorham

  • 1Department of Medical Microbiology, Molecular Virology Section (HPC EB88), University Medical Center Groningen and University of Groningen, P.O. Box 30.001, 9700 RB Groningen, Netherlands.

Journal of Virology
|September 2, 2011
PubMed

Insights

Antibodies targeting immature flaviviruses, like West Nile virus and dengue virus, can unexpectedly make them infectious. This process relies on cell entry and furin protease activity, with some viruses needing more acidic conditions for activation.

Area of Science:

  • Virology
  • Immunology
  • Molecular Biology

Background:

  • Flaviviruses exist as mature, partially immature, and fully immature particles.
  • Immature flaviviruses are noninfectious due to the prM protein inhibiting attachment and fusion.
  • Anti-prM antibodies can facilitate entry and subsequent furin-mediated prM processing, rendering immature virions infectious.

Purpose of the Study:

  • To investigate the infectious potential of fully immature West Nile virus (WNV) and dengue virus (DENV) particles opsonized with the E53 monoclonal antibody (MAb).
  • To determine if E53, an antibody targeting the fusion-loop peptide, can confer infectivity to immature flaviviruses.
  • To explore the role of cell entry and endosomal furin activity in E53-mediated flavivirus infection.

Main Methods:

  • Opsonization of immature WNV and DENV particles with E53 MAb.
  • Assessment of infectivity following antibody opsonization.
  • Investigation of the dependence on cell entry and endosomal furin activity.
  • pH-dependent analysis of prM cleavage by furin.

Main Results:

  • E53 MAb opsonization rendered fully immature WNV and DENV infectious, similar to anti-prM antibodies.
  • E53-mediated enhancement of infectivity required efficient cell entry and endosomal furin enzymatic activity.
  • E53-opsonized immature DENV, but not WNV, required a more acidic pH for efficient prM cleavage by furin.

Conclusions:

  • Antibodies targeting conserved epitopes on immature flaviviruses can induce infectivity.
  • The mechanism involves antibody-facilitated entry and subsequent furin-mediated processing of the prM protein.
  • Virus-specific differences in pH requirements for furin cleavage highlight the complexity of antibody-mediated flavivirus infection dynamics.

More Related Videos

A High-throughput Cre-Lox Activated Viral Membrane Fusion Assay to Identify Inhibitors of HIV-1 Viral Membrane Fusion07:22

A High-throughput Cre-Lox Activated Viral Membrane Fusion Assay to Identify Inhibitors of HIV-1 Viral Membrane Fusion

Published on: August 14, 2018

Assessment of Immunologically Relevant Dynamic Tertiary Structural Features of the HIV-1 V3 Loop Crown R2 Sequence by ab initio Folding10:50

Assessment of Immunologically Relevant Dynamic Tertiary Structural Features of the HIV-1 V3 Loop Crown R2 Sequence by ab initio Folding

Published on: September 15, 2010

Related Concept Videos

Inhibitors of Virion Maturation and Assembly01:19

Inhibitors of Virion Maturation and Assembly

As part of their replication cycle, certain viruses synthesize long precursor proteins called polyproteins within infected host cells. In human immunodeficiency virus (HIV), two major polyproteins are produced: Gag and Gag-Pol. The Gag polyprotein supplies the structural components of the virus, while Gag-Pol includes essential viral enzymes such as reverse transcriptase, integrase, and protease. After synthesis, these polyproteins move to the host cell membrane, where they assemble into an...
Leaky Scanning02:28

Leaky Scanning

During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA.  Marilyn Kozak discovered that the sequence RCCAUGG (where R stands for...
Inhibitors Of Virion Release01:25

Inhibitors Of Virion Release

Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated...
Immune Response Against Viral Pathogens01:29

Immune Response Against Viral Pathogens

The immune system's response to viral infections is a complex and coordinated process involving natural killer (NK) cells, T cell-mediated responses, and antibody-mediated responses.
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
Influenza01:27

Influenza

Influenza is an acute, highly communicable viral disease that affects the respiratory tract and is responsible for seasonal epidemics worldwide. Influenza A is the most prevalent type associated with widespread outbreaks and is subtyped based on two surface glycoproteins: hemagglutinin (H) and neuraminidase (N), as in H1N1. These glycoproteins are essential for viral infectivity, transmission, and immune recognition. Transmission occurs primarily through respiratory droplets and contaminated...
Affinity and Avidity01:41

Affinity and Avidity

Overview