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Related Experiment Video

Updated: Jun 18, 2025

Engineering Antiviral Agents via Surface Plasmon Resonance

Engineering Antiviral Agents via Surface Plasmon Resonance

Published on: June 14, 2022

SARS-CoV-2 Accessory Protein ORF8 Targets the Dimeric IgA Receptor pIgR.

Frederique Laprise^1,2, Ariana Arduini^1,3, Mathew Duguay^1,4

¹Lady Davis Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada.

|July 27, 2024

Summary

The SARS-CoV-2 virus uses its ORF8 protein to reduce the expression of a key immune receptor, polymeric Ig receptor (pIgR). This viral strategy helps SARS-CoV-2 evade the host

Keywords:

IgA IgM ORF8 SARS-CoV-2 mucosal immunity pIgR

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Published on: July 29, 2014

Area of Science:

Virology and Immunology
Molecular Biology
Respiratory Pathogens

Background:

SARS-CoV-2 infection targets the respiratory mucosa, but mechanisms of immune evasion are not fully understood.
Polymeric Ig receptor (pIgR) is crucial for mucosal immunity, transporting dimeric IgA (dIgA) and pentameric IgM (pIgM) to neutralize pathogens.
Reduced pIgR expression is observed in COVID-19 patients, suggesting a role in pathogenesis.

Purpose of the Study:

To investigate how SARS-CoV-2 antagonizes host mucosal immunity.
To identify SARS-CoV-2 proteins involved in downregulating pIgR expression.
To elucidate the role of ORF8 in SARS-CoV-2-mediated immune evasion at the mucosal level.

Main Methods:

Studied the interaction between SARS-CoV-2 proteins and pIgR.
Assessed the effect of viral proteins on pIgR expression levels.
Investigated the binding of ORF8 to cell surface pIgR and its functional consequences.

Main Results:

The viral accessory protein Open Reading Frame 8 (ORF8) was found to potently downregulate pIgR expression.
ORF8's downregulation of pIgR correlates with its interaction with the receptor, diminishing dIgA and pIgM binding.
ORF8 from variants of concern retains this pIgR downregulation activity, highlighting its conserved role in pathogenesis.

Conclusions:

SARS-CoV-2 ORF8 protein plays a significant role in antagonizing mucosal immunity by downregulating pIgR.
This conserved mechanism of immune evasion is important for SARS-CoV-2 pathogenesis.
ORF8's interaction with pIgR impairs the transport of protective antibodies, contributing to viral persistence.