Kayo Inaba

Introduction: Cutaneous Dendritic Cells: Distinctive Antigen-Presenting Cells for Experimental Models and Disease States

Cutaneous dendritic cells, which include the Langerhans cells (LC) of the epidermis as well as their counterparts in the dermis and cutaneous lymph, have provided a rich area for investigative dermatology and immunology. The important starting points were the findings that LC are bone marrow-derived and have many properties of white blood cells such as binding of immune complexes, expression of major histocompatibility complex (MHC) class II products, and presentation of antigens to T cells. Much of this work is discussed in a compendium, Epidermal Langerhans Cells, edited by Dr. G. Schuler and published by CRC Press, Boca Raton, FL in 1991. Here, Dr. Heidrun Moll assembles an important series of articles that cover the latest, most timely developments.

The Role and Mechanism of Action of Dendritic Cells in Transplantation Immunity

Transplantation immunity provides an important model for studying the function of accessory cells in T-dependent responses. Class II MHC products, when presented as dendritic cells, are powerful immunogens for alloreactive helper T lymphocytes. Class II products on other leukocytes—B cells, macrophages, and epidermal Langerhans cells—are poor immunogens but actively stimulate primed T lymphoblasts. The stimulating activity of dendritic cells can in part be ascribed to their capacity to aggregate T lymphocytes by an antigen-independent mechanism. Dendritic–T cell aggregates represent the milieu in which helper T cell activation occurs in culture.