ABSTRACT
Introduction Interleukin-10 (IL-10) is a pleiotropic cytokine produced by activated T cells, B cells, mono-
cytes/macrophages, mast cells and keranocytes (reviewed in ref. 1). IL-10 was first recognized as a cytokine synthesis inhibitory factor1'3 due to its ability to suppress macrophages, inhibit ing production of a number of cytokines, and an ability to serve as accessory cells for stimula tion of T cell and natural killer cell function.4'7 It also exhibits some stimulatory activity for proliferation and differentiation of B cells, mast cells, and T cells.8 Biologically functional human IL-10 is a 36 kDa dimer1,9,10 consisting of two 160 amino acid residue long polypep tide chains. In order to initiate signal transduction, IL-10 requires two receptor chains, IL-10R1 and IL-10R2.12 Both chains contain extracellular, transmembrane and intracellular domains, and belong to class II or interferon receptor family.13,14 That family is characterized by the presence of two particular disulfide bridges and the absence of the so called “WSXWS motif” in the C-terminal part of the extracellular domain.
