Functional intercellular adhesion molecule-3 is expressed by freshly isolated epidermal Langerhans cells and is not regulated during culture.
Activation of T lymphocytes by antigen-presenting cells requires the interaction of major histocompatibility complex/antigen complexes with the T-cell receptor as well as the binding of co-stimulatory molecules to receptors on T cells. Freshly isolated epidermal Langerhans cells (LC) do not display a significant number of co-stimulatory molecules. After short-term culture, LC express and then upregulate intercellular adhesion molecule-1 (ICAM-1) (CD54), leukocyte function-associated antigen (LFA)-3 (CD58), and B7-1 (CD80) accessory molecules and exhibit an enhanced antigen-presenting function. The present study examined the presence on human LC of the LFA-1 ligands ICAM-2 (CD102) and ICAM-3 (CD50) and their functional role in the activation of allogeneic T cells. Immunohistochemistry of skin sections and flow-cytometry analysis of freshly procured epidermal cell suspensions showed that LC (CD1a+ or HLA-DR+) expressed ICAM-3 but not ICAM-2. After 48-72-h culture in the presence of granulocyte/macrophage colony-stimulating factor, LC did not stain for ICAM-2 but expressed ICAM-3 at the same level as fresh cells. Incubation of both freshly isolated and cultured LC with monoclonal antibodies directed against ICAM-3 reduced T-cell proliferation (25-75% inhibition) in the primary allogeneic mixed leukocyte reaction assay; incubation of cultured LC with anti-ICAM-1 and anti-ICAM-3 synergistically reduced T-cell response. The results indicate that ICAM-3 is constitutively expressed and represents an important costimulatory molecule on freshly isolated LC but, in contrast to other accessory molecules, is not subjected to regulation during LC culture.[1]References
- Functional intercellular adhesion molecule-3 is expressed by freshly isolated epidermal Langerhans cells and is not regulated during culture. Zambruno, G., Cossarizza, A., Zacchi, V., Ottani, D., Luppi, A.M., Giannetti, A., Girolomoni, G. J. Invest. Dermatol. (1995) [Pubmed]
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