Characterization of specific leukotriene C4 binding sites on cultured human keratinocytes.

Peptidoleukotriene C4 (LTC4) and leukotriene B4 (LTB4) are both suspected of being inflammatory mediators and epidermal mitogenic agents in cutaneous psoriatic lesions. In the present study an LTC4 specific binding site was characterized in membranes from cultured human keratinocytes (Kd, 8.7 nmol/l; Bmax, 1.2 pmol/mg protein). In contrast LTB4 did not show any high affinity binding which could account for its biological effects. These data suggest that LTC4, unlike LTB4, acts on epidermal cells through a receptor-mediated mechanism.