Lung Megakaryocytes are Immune Modulatory Cells

Our data demonstrate that lung and bone marrow-derived megakaryocytes (Mks) have distinct immune phenotypes and functions; lung Mks secrete inflammatory cytokines and express molecules that are similar to many tissue resident leukocytes and antigen presenting cells (APCs), and lung Mks process live intact bacteria and present bacteria-derived antigen to CD4+ T cells both in vitro and in vivo. Our in vivo data suggest that lung Mks have important roles in the early activation of T cell responses to a pulmonary pathogen challenge, identifying a novel immune regulatory role for lung Mks. Cells were isolated from either the lung or the bone marrow, and enriched for the megakaryocyte population. Single cell RNA-seq was subsequently performed on isolated cells.