Dynamic nature and function of epidermal langerhans cellsin vivo andin vitro: a review, with emphasis on human Langerhans cells

Abstract

Epidermal Langerhans cells (LC) are Birbeck granule-containing bone-marrow-derived cells, which are located mainly in the suprabasal layer of the epidermis. They can be readily identified by their strong expression of CD1a and MHC class II molecules. In addition to these 'classical' properties, an extensive phenotypic profile of normal human LC, summarized in this review, is now available. The powerful capacity of LC to activate T lymphocytes is clearly documented and, to date, LC are recognized as the prominent antigen-presenting cells of the skin immune system. They are generally believed to pick up antigens encountered in the epidermis and to migrate subsequently from the epidermis to the skin-draining lymph nodes. Upon arrival in the paracortex of lymph nodes, the antigen-laden LC transform into interdigitating cells and they present antigen to naive T lymphocytes in a MHC class II-restricted fashion; this results in the generation of antigen-specific immune responses. It has also been demonstrated that transformation of LC into interdigitating cells occurs when LC are cultured in vitro. Both in vivo and in vitro studies have indicated that properties of LC, such as phenotype, morphology and the stimulatory potential to activate T lymphocytes, are dependent on the local microenvironment in which the LC reside. The essential role of LC in the induction of contact allergic skin reactions and skin transplant rejection is well established.

Modulation of the Bovine Delayed-Type Hypersensitivity Responses to Defined Mycobacterial Antigens by a Synthetic Bacterial Lipopeptide

“…We considered that the explanation for the exquisite sensitivity of guinea pigs to induce DTH compared with the sensitivities of other hosts may be related to differences in the cellular compositions of the dermis and epidermis. The cells present in the skin that have an important role in mediating DTH include mast cells, which increase vascular permeability through the release of vasoactive amines (2,16), and Langerhans cells, which are potent antigen-presenting cells of the DC lineage (39). However, a review of literature indicated that the densities of Langerhans cells in the epidermis of guinea pigs and in the epidermis of cattle are equivalent (6,38), while the densities of mast cells in cattle dermis and human dermis are actually greater than the density observed in guinea pigs (17,28).…”

The Kinetics of Langerhans Cells in Equine Insect Hypersensitivity "Kasen".

“…It has been suggested that these lesions result from Type I and Type IV allergic dermatitis [22]. Allergic contact dermatitis (ACD) is a form of Type IV allergic reaction, and may be considered to consist of two stages [2,3,11,20]. The sensitization phase occurs at the first contact of skin with the hapten.…”

Studies on the Histogenesis of Myxomatous Tissue of Human Coronary Lesions

“…This cell family is a phenotypically and functionally diverse population of cells that actively migrate from bone marrow via the blood circulation to the peripheral organs, where they function as antigen-presenting cells responsible for induction of primary immune responses. 21,25,28 A typical member of this family, LCs, are usually distributed in the suprabasal layer of the epidermis. 21 These cells display major histocompatibility complex (MHC) class I and II antigens (CD1a and human leukocyte antigen [HLA]-DR), S100 antigen, and several adhesion molecules.…”

“…21,24 -27 DCs function as antigen-presenting cells and are involved in various immune system-mediated, neoplastic, and infectious diseases. 21,25,28 Another alternative source of origin of stellate cells could be mesenchymal cells with temporary differentiation as pericytes or myofibroblasts. There are reports that migrating adventitial myofibroblasts may contribute to the process of lesion formation after balloon overstretch injury in a swine model.…”