Granulocyte-macrophage colony-stimulating factor promotes differentiation and survival of human peripheral blood dendritic cells in vitro

Interest in human dendritic cells (DC) has been heightened recently by the discovery that this cell type is a primary target of the human immunodeficiency virus, the causative agent of AIDS. DC are bone marrow-derived cells with an extraordinarily potent ability to promote the immunological activity of T lymphocytes. Unfortunately, since DC constitute less than 0.5% of peripheral blood mononuclear cells and die within a few days of their isolation, they are not readily accessible to study. We report here that granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine with well-recognized effects on granulocyte and macrophage maturation, profoundly affects the morphology and viability of DC isolated from peripheral blood. GM-CSF not only promotes DC survival but also induces DC differentiation to mobile, reversibly adherent cells with long-branched projections. DC cultured in GM-CSF survive for up to 6 wk and retain their ability to stimulate the proliferation of T cells in allogeneic and autologous mixed leukocyte reactions.