Lymphocyte emperipolesis in human glial cells

Astrocytes have been observed to contain intact, viable lymphocytes within their cytoplasm (emperipolesis) in multiple sclerosis plaques and some brain tumors. This study characterizes the adhesive, emperipoletic and phagocytic properties of glial cells in culture. Human fetal and adult astrocytes engaged in adhesion and emperipolesis of lymphocytes. Emperipolesis, and not adhesion, was temperature- and cation-dependent. The CD8 and MHC Class I antigens played a role in emperipolesis. Lymphocytes most often remained viable within the cytoplasm of astrocytes but occasionally underwent lysis or caused disruption of the astrocyte intermediate filaments. The phenomenon of emperipolesis is distinct from phagocytosis, since microglia showed prominent phagocytic properties but did not engage in emperipolesis. Conversely, astrocytes were efficient emperipolites and rarely demonstrated phagocytic properties.