Degwert, J., F. Steckel, U. Hoppe and L. H. Kligman. In Vitro Model for Contact Sensitization: I. Stimulatory Capacities of Human Blood-derived Dendritic Cells and their Phenotypical Alterations in the Presence of Contact Sensitizers. Toxic. in Vitro 1997. 11: 613-618. [Reprinted with permission from Elsevier Science]

sodium lauryl sulfate - 00629-25-4; benzalkonium chloride - 08001-54-5; urushiol - 53237-59-5; primin - 15121-94-5; alantolactone - 00546-43-0; isoalantolactone - 00470-17-7; nickel sulfate - 07786-81-4

Dendritic cells (DC) are highly specialized antigen-presenting cells (APC) located in many non-lymphoid tissues and a specialized form of DC--the Langerhans cell (LC)--is found in the skin. The functionality of LC as APC is crucial for the induction of an allergic contact dermatitis. For a long time LC research has been hampered by the limiting numbers of functionally active LC that could be isolated from human skin. The addition of GM-CSF and IL-4 to the non-adherent fraction of mononuclear cells from peripheral blood generated a large amount of CD1a⁺HLA-DR⁺DC. These in vitro-generated DC exhibited the morphology, phenotype and autologous T-lymphocyte stimulating capacity of the human DC/LC system. We had tested phenotypical alterations of in vitro-generated DC under the influence of subtoxic concentrations of different chemicals and contact sensitizers. In vitro stimulation with the contact sensitizers urushiol, primin, C10- and C11-primin analogues, alantolactone, isoalantolactone and NiSO₄ resulted in a decrease of HLA-DR expression on the surface of these cells if the incubation period did not exceed 3 hr. Incubation with irritants like sodium lauryl sulfate (SLS) and benzalkonium chloride did not change or increase the HLA-DR surface expression under these conditions. With regard to the adhesion molecule ICAM-1, there was no clear difference between irritants and contact sensitizers. But based on the alteration of HLA-DR expression of dendritic cells under short-term exposure conditions, there was a clear-cut difference between irritants and contact sensitizers. In summary, this system can be used to discriminate between contact sensitizers and irritants.