ABSTRACT
Human peripheral blood dendritic cells have a potent antigen-presenting capability for recruiting resting or primary T lymphocytes into immune responses. Once isolated at 36 to 48 hours post-venipuncture, dendritic cells maintain a stable phenotype and morphology, and it appears that they are terminally differentiated. By transmission electron microscopy, human blood dendritic cells are large cells with an abundant cytoplasm and very numerous mitochondria consistent with an active and highly motile cell. Human blood dendritic cells strongly express common epitopes of the leukocyte common antigen which is a marker for cells of hematopoietic origin and is likely to play a role in signal transduction and regulation. One method of studying the interactions between human blood dendritic cells and T cells has been the use of monoclonal antibodies that interfere with these interactions. Mammalian peripheral blood dendritic cells represent a subset of bone marrow-derived mononuclear leukocytes with morphological, immunophenotypic, and functional characteristics that distinguish them from monocytes.
