Related Experiment Video
Updated: Jun 10, 2025
An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
A complex remodeling of cellular homeostasis distinguishes RSV/SARS-CoV-2 co-infected A549-hACE2 expressing cell
Claudia Vanetti1, Irma Saulle1,2, Valentina Artusa1,2
1Department of Biomedical and Clinical Sciences, University of Milan Milan Italy.
Abstract:
Concurrent infections with two or more pathogens with analogous tropism, such as RSV and SARS-CoV-2, may antagonize or facilitate each other, modulating disease outcome. Clinically, discrepancies in the severity of symptoms have been reported in children with RSV/SARS-CoV-2 co-infection. Herein, we propose an in vitro co-infection model to assess how RSV/SARS-CoV-2 co-infection alters cellular homeostasis. To this end, A549-hACE2 expressing cells were either infected with RSV or SARS-CoV-2 alone or co-infected with both viruses. Viral replication was assessed at 72 hours post infection by droplet digital PCR, immunofluorescence, and transmission electron microscopy. Anti-viral/receptor/autophagy gene expression was evaluated by RT-qPCR and confirmed by secretome analyses and intracellular protein production. RSV/SARS-CoV-2 co-infection in A549-hACE2 cells was characterized by: 1) an increase in the replication rate of RSV compared to single infection; 2) an increase in one of the RSV host receptors, ICAM1; 3) an upregulation in the expression/secretion of pro-inflammatory genes; 4) a rise in the number and length of cellular conduits; and 5) augmented autophagosomes formation and/or alteration of the autophagy pathway. These findings suggest that RSV/SARS-CoV-2 co-infection model displays a unique and specific viral and molecular fingerprint and shed light on the viral dynamics during viral infection pathogenesis. This in vitro co-infection model may represent a potential attractive cost-effective approach to mimic both viral dynamics and host cellular responses, providing in future readily measurable targets predictive of co-infection progression.
Insights
RSV and SARS-CoV-2 co-infection in cells increases RSV replication and inflammation. This study developed an in vitro model to understand how these viruses interact, revealing unique cellular responses and potential targets for predicting disease progression.
Area of Science:
- Virology
- Cellular Biology
- Immunology
Background:
- Concurrent viral infections, like Respiratory Syncytial Virus (RSV) and SARS-CoV-2, can alter disease severity.
- Discrepancies in symptom severity are observed in co-infected children.
Purpose of the Study:
- To establish an in vitro co-infection model for RSV and SARS-CoV-2.
- To investigate the impact of co-infection on cellular homeostasis and viral dynamics.
Main Methods:
- A549-hACE2 cells were infected with RSV, SARS-CoV-2, or both.
- Viral replication was quantified using droplet digital PCR, immunofluorescence, and electron microscopy.
- Gene expression (antiviral, receptor, autophagy) and secretome were analyzed via RT-qPCR and protein assays.
Main Results:
- RSV replication increased in co-infected cells compared to single infection.
- RSV receptor ICAM1 expression was elevated.
- Pro-inflammatory gene expression and secretion were upregulated.
- Cellular conduits and autophagosome formation/autophagy pathways were altered.
Conclusions:
- RSV/SARS-CoV-2 co-infection exhibits a distinct molecular and viral signature in vitro.
- The model provides insights into viral pathogenesis and host cellular responses.
- This model offers a cost-effective approach to identify predictive biomarkers for co-infection progression.
