Expression and modulation of the Lewis x antigen (CD15) on the T cell line Molt-4

The T cell lines Molt-4 and H9 exhibited a characteristic distribution of the cell adhesion molecule Lewis x (CD15, lacto-N-fucopentanose III) showing an unusually broad peak by flow cytometry ranging from cells, without CD15 to cells with high expression. The cytokines IL-1, IL-2, IFN-beta, IFN-gamma, and TNF-alpha, known to activate T cells, did not affect CD15 expression, However, phorbol myristate acetate and the thymic peptide extract Thymex-L were able to enhance both the number of CD15-positive cells and the median fluorescence, The effects of both inducers were dose- and time-dependent, An additive or synergistic effect was not seen, These data suggest that phorbol esters and distinct thymic peptides can modulate the expression of the cell surface antigen CD15. (C) 1997 Federation of European Biochemical Societies.