FLOW CYTOMETRIC ANALYSIS OF CYTOKINE RECEPTORS ON HUMAN LANGERHANS CELLS - CHANGES OBSERVED AFTER SHORT-TERM CULTURE

It is well established that granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1 and tumour necrosis factor-alpha ( TNF-alpha) are involved in Langerhans' cell (LC) development and dendr itic cell traffic. However, little is known about the pattern of cytok ine receptors on human LC and their modulation during different stages of maturation. The expression of cytokine receptors was studied by fl ow cytometry on both freshly isolated LC(fLC) and 72-hr cultured LC (c LC). Epidermal cell suspensions enriched in LC were obtained after ski n trypsinization and Ficoll-Hypaque gradient. LC were identified by th eir CD1a positivity. Although the majority of fLC were positive for th e alpha chain of GM-CSF receptor (GM-CSFR), the beta chain of GM-CSFR was detected only on 15% of CD1a(+) cells, fLC were also positive for IL-1 receptor (IL-IR) type 1, IL-IR type 2, 75 000 molecular weight TN F receptor (TNFR) and interferon-gamma receptor (IFN-gamma R). IL-6R a nd its transducing signal gp130 were present in a subset of fLC. Granu locyte colony-stimulating factor receptor (G-CSFR), macrophage colony- stimulating factor receptor (M-CSFR), the alpha and beta chain of IL-2 R, IL-4R, IL-7R, IL-8R and 55 000 molecular weight TNFR were not detec ted on fLC. After culture, LC up-regulated the expression of both the alpha and beta chains of GM-CSFR, IL-1R type 2, alpha and beta chains of IL-2R, IL-BR and gp130. In contrast, IL-1R type 1 and 75 000 molecu lar weight TNFR were down-modulated and the expression of IFN-gamma R was not affected by culture. These results suggest that LC undergo cha nges in the cytokine receptor repertory during in vitro maturation.