Epidermal lymphocyte chemotactic factor specifically attracts OKT4-positive lymphocytes.

Epidermal lymphocyte chemotactic factor (ELCF) from skin overlying a positive tuberculin reaction was compared with the chemoattractants leukotriene B4 (LTB4), N-formyl-methionyl-leukyl-phenylalanine (FMLP), and complement split product C5a (C5a). The chemotactic assay used is a modified Boyden chamber technique. The lymphocytes were subsets of T lymphocytes from healthy young individuals first separated by flotation of E rosettes on Isopaque Ficoll followed by incubation of T cells with anti-CD4 and anti-CD8 monoclonal antibodies and further separation using fluorescence-activated cell sorting. ELCF specifically attracted OKT4+ lymphocytes, while LTB4, FMLP, and C5a induced significant migration in both OKT4+ and OKT8+ lymphocytes without any clear difference between the various chemoattractants or cell populations. We found no blocking of the chemotactic capacity of ELCF when we added antibodies towards IL-1 alpha and IL-1 beta to the chemotactic assay. Further recombinant IL-1 alpha and Il-1 beta did not induce any chemotactic response. Our observation may be of significance in explaining the predominance of OKT4+ cells in allergic contact dermatitis and certain other skin diseases.