[Dendritic cells and tumor specific immunity].
Dendritic cells (DCs) are the most efficient antigen presenting cells (APCs) that initiate and modulate our internal immune responses in stimulating both B cells to produce various antibodies and T cells to control cell-mediated immunity. Such DCs can be classified into three groups based on their origin. One is the myeloid DCs originating from CD34+ stem cells that are further differentiated into CD14+ CD1a- phagocytotic, glass-adherent macrophages with the help of M-CSF, or into CD14- CD1a+, Birbeck granule containing LAG-1+ Langerhans cells by GM-CSF, TNF-alpha and TGF-beta 1 stimulation. The latter Langerhans cells appear to differentiate into DC1 as strong stimulators of T cells displaying large amounts of MHC-peptide complexes and co-stimulatory molecules, such as B7-1 and B7-2, after capturing antigens and migrating to a regional lymphoid organ. The second group is the lymphoid DCs originating from CD4+CD11c- cells, which differentiate into DC2 when cultured with IL-3. Third is the follicular dendritic cells (FDC) observed in lymphofollicules that capture foreign antigens with their Fc-receptor or complement-receptors and keep the antigens inside the follicules. DC1s secrete IL-12, which turns CD4 T cells into Th1 cells to induce cellular immunity, whereas DC2s favor production of Th2 cells to organize humoral immunity. Therefore, DCs appear to control our internal self-defense system. These unique features of DCs enable us to manipulate Th1 and Th2 activation selectively, and thus antigen-pulsed DCs are currently thought of as excellent tools to induce specific T cell immunity towards virus-infected cells or tumor cells.
Takahashi
H
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Department of Microbiology and Immunology, Nippon Medical School, Tokyo, Japan.
D000818:Animals; D015704:CD4 Antigens / Q000276:immunology; D002454:Cell Differentiation / Q000502:physiology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D007694:Killer Cells, Natural / Q000276:immunology; D018950:Lipopolysaccharide Receptors / Q000276:immunology; D008264:Macrophages; D051379:Mice; D009369:Neoplasms / Q000276:immunology* / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology
D015704:CD4 Antigens; D018950:Lipopolysaccharide Receptors