Th30 - Use of Ex Vivo Lung Perfusion to Study the Immune Response to Influenza Viral Challenge in Human Lung

Abstract Text: Lung tissue resident immunity is critical for protection from influenza. Studies of tissues from human organ donors have identified cells that are transcriptionally similar to murine resident immune cells but these studies are limited because they evaluate cells in tissues at a single time point only. Ex vivo lung perfusion (EVLP) is a clinical bridge-to-transplant modality that maintains human lung viable over 4-6 hours. We hypothesized that EVLP can facilitate longitudinal studies of the immune response to influenza A virus (IAV) in the human lung. To test this hypothesis, we selectively challenged the right middle lobe (RML) of N= 5 human lungs on EVLP with varying titers of pandemic H1N1 influenza A virus (A/California/07/2009) virus and assayed for viral PCR and immune cells in bronchoalveolar lavage fluid (BAL) over 18-24 hours. We amplified the M gene of H1N1 IAV only from RML BAL We identified an increase in BAL cellularity over time only in the RML that comprised CD4+ and CD8+ T cells. We found CD4+ and CD8+ T cells from the RML BAL alone were proliferating (Ki-67+). Next, we adapted the activation induced marker (AIM) assay, routinely used to identify antigen-specific T cells in human blood, to enumerate antigen-specific T cells in BAL. Using this modified AIM assay, we found antigen-specific CD4+ and CD8+ T cells as expanded over time in the RML following IAV. Collectively, these data suggest that we can successfully study the immune response to IAV in human lung over time using EVLP.