Mitochondrial and endoplasmic reticulum morphology of human bone marrow plasma cell subsets by high resolution confocal imaging 4318

Abstract Description Plasma cells represent a critical defense against infectious diseases, owing to their role as antibody-producing cells. Long-lived plasma cells reside in the bone marrow and are the source of pathogen-specific antibodies that can be detected in circulation decades after infection. Currently, we lack a fundamental understanding of bone marrow plasma cell diversity within healthy humans. Unique plasma cell phenotypes may correspond to functional and morphological differences. Importantly, mitochondrial and endoplasmic reticulum (ER) processes are essential to support the metabolic requirements of antibody production and long-term survival. Here, we isolated 5 phenotypically-distinct plasma cell subsets from 4 healthy human bone marrow donors and analyzed their cellular morphology, and the activity and structures of their mitochondria and ER by high-resolution imaging. We evaluated active mitochondria with MitoTracker and ER with protein disulfide isomerase staining and analyzed cells by confocal microscopy. Cellular morphology and cytoplasmic volume were analyzed by differential interference contrast imaging. Our results indicated unique organelle activity and structures across bone marrow plasma cell subsets. Collectively, our data provides insight into healthy human plasma cell diversity, which can be applied to study these cells in the context of cancer and vaccination. Funding Sources Paul G. Allen Family Foundation Topic Categories Immune Mechanisms of Human Disease (HUM)