Epithelial Memory After Respiratory Viral Infection in Mice Results in Prolonged Enhancement of Antigen Presentation

Viral lower respiratory tract infections (LRTIs) can reduce the severity of subsequent LRTIs but have also been linked to respiratory allergy development and exacerbation. Here, we show that viral LRTI can imprint lung epithelial cells (LECs), leading to prolonged phenotypic and functional changes.

Mice were infected via intranasal administration of respiratory syncytial virus (RSV). After 28 days, LECs were isolated using cold dispase digestion followed by magnetic-activated cell sorting. Epigenetic changes were assessed using Cleavage Under Targets and Release Using Nuclease (CUT&RUN), while transcriptional changes were evaluated using NanoString and qPCR. Flow cytometry was employed to measure cell surface major histocompatibility complex (MHC) levels, antigen uptake and processing rates, and OT-I cell proliferation after antigen presentation.

We identified epigenetic and transcriptomic changes in murine LECs 28 days after RSV infection, especially impacting genes associated with MHC. Lasting upregulation of MHC-I and MHC-II was further increased following in vivo LPS stimulation. Importantly, MHC upregulation was associated with increased antigen uptake and processing, as well as increased antigen presentation to T cells.

Our data demonstrate that RSV can induce prolonged upregulation of antigen presentation by LECs, with the potential to facilitate local T cell responses to microbial antigens and allergens and to enhance immunity or in susceptible hosts respiratory allergy.