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Use of Viral Entry Assays and Molecular Docking Analysis for the Identification of Antiviral Candidates against Coxsackievirus A16
Published on: July 15, 2019
In Vitro Characterization of Neutralizing Hen Antibodies to Coxsackievirus A16
Pharaoh Fellow Mwale1,2, Chi-Hsin Lee1,2, Peng-Nien Huang3
1Ph.D. Program in Medical Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei 110301, Taiwan.
Insights
New single-chain variable fragment (scFv) antibodies show promise in neutralizing Coxsackievirus A16 (CA16), a cause of hand, foot, and mouth disease (HFMD). These antibodies may offer a potential treatment for CA16 infections in young children.
Area of Science:
- Virology
- Immunology
- Biotechnology
Background:
- Coxsackievirus A16 (CA16) is a primary cause of hand, foot, and mouth disease (HFMD), predominantly affecting children under five.
- While typically mild, CA16 HFMD can lead to severe complications, including aseptic meningitis and mortality.
- There are currently no available vaccines or antiviral therapies for CA16 infection.
Purpose of the Study:
- To develop novel therapeutic strategies against CA16 infection using antibody-based approaches.
- To investigate the potential of single-chain variable fragment (scFv) antibodies for neutralizing CA16.
- To evaluate the cross-reactivity and neutralizing capabilities of developed antibodies against related enteroviruses.
Main Methods:
- Construction of scFv phage display libraries from immunized laying hen splenocytes.
- Expression of scFv molecules in *Escherichia coli* using the pComb3X vector and helper phages.
- Screening and selection of effective scFv clones through bio-panning and ELISA assays.
- Assessment of neutralizing activity against CA16 and cross-reactivity with EV71 viral proteins.
Main Results:
- An effective scFv antibody clone with significant binding activity to CA16-infected lysate proteins was identified.
- The selected scFv clone demonstrated neutralizing capability against CA16 and cross-reacted with EV71 proteins.
- Polyclonal IgY antibodies also exhibited specific binding and significant neutralization of CA16, without cross-reacting with EV71 proteins.
Conclusions:
- Both IgY and scFv antibodies show protective potential against CA16 viral infection in vitro.
- These antibodies represent promising candidates for the development of treatments for CA16 infection, particularly in vulnerable young children.
- Further research is warranted to explore the therapeutic application of these antibodies in vivo.
Abstract:
Coxsackievirus A16 (CA16) is one of the major causative agents of hand, foot, and mouth disease (HFMD). Children aged <5 years are the most affected by CA16 HFMD globally. Although clinical symptoms of CA16 infections are usually mild, severe complications, such as aseptic meningitis or even death, have been recorded. Currently, no vaccine or antiviral therapy for CA16 infection exists. Single-chain variable fragment (scFv) antibodies significantly inhibit viral infection and could be a potential treatment for controlling the infection. In this study, scFv phage display libraries were constructed from splenocytes of a laying hen immunized with CA16-infected lysate. The pComb3X vector containing the scFv genes was introduced into ER2738 Escherichia coli and rescued by helper phages to express scFv molecules. After screening with five cycles of bio-panning, an effective scFv antibody showing favorable binding activity to proteins in CA16-infected lysate on ELISA plates was selected. Importantly, the selected scFv clone showed a neutralizing capability against the CA16 virus and cross-reacted with viral proteins in EV71-infected lysate. Intriguingly, polyclonal IgY antibody not only showed binding specificity against proteins in CA16-infected lysate but also showed significant neutralization activities. Nevertheless, IgY-binding protein did not cross-react with proteins in EV71-infected lysate. These results suggest that the IgY- and scFv-binding protein antibodies provide protection against CA16 viral infection in in vitro assays and may be potential candidates for treating CA16 infection in vulnerable young children.
