Adhesion molecules on the plasma membrane of epidermal cells. II. The intercellular adhesion molecule-1 is constitutively present on the cell surface of human resting Langerhans cells.
The intercellular adhesion molecule-1 (ICAM-1), which is a member of the immunoglobulin superfamily, is expressed on many cell types, including a variety of cells showing accessory/antigen-presenting capacities and belonging to the monocyte/macrophage or dendritic lineages. Here it is shown that human freshly isolated Langerhans cells (LC) constitutively express ICAM-1, as expected. It seems likely that the amounts of ICAM-1 moieties expressed on the plasma membrane of resting LC are only limited, since they virtually escaped detection by conventional immunofluorescence procedures on epidermal sheets. However, all the observed Birbeck granule-bearing LC showed their clear, although relatively weak, ICAM-1 positivity when more sensitive techniques were employed, such as colloidal gold-immunoelectronmicroscopy using gold particles 15nm in size and, to an even higher extent, using gold particles 5 nm in size. Because ICAM-1 is a ligand for the adhesive molecule LFA-1, which is expressed on the surface of leukocytes and, especially, lymphocytes, the ICAM-1 (LC)/LFA-1 (T-lymphocytes) interactions might, enabling these cells to adhere together, deliver activation signals to T cells, thus constituting the initial event in the generation of a cutaneous immune response.
De Panfilis
G
G
Department of Dermatology, Parma University, Italy.
Manara
G C
GC
Ferrari
C
C
Torresani
C
C
D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006046:Gold; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D007801:Langerhans Cells / Q000378:metabolism*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D012146:Rest
D015815:Cell Adhesion Molecules; D018799:Intercellular Adhesion Molecule-1; D006046:Gold