Cytokines Interleukins and tumour necrosis factor

Most of the interleukins are produced by a number of different cell types. At least 17 different cell types are capable of producing IL-1, and IL-8 is produced by at least 10 distinct cell types. On the other hand, IL-2, -9 and -13 are produced only by T-lymphocytes. 

Nearly all of the interleukins are soluble molecules (one form of IL-1 is cell associated). They promote their biological response by binding to specific receptors on the surface of target cells. Most interleukins exhibit paracrine activity (i.e. the target cells are in the immediate vicinity of the producer cells), although some display autocrine activity (e.g. IL-2 can stimulate the growth and differentiation of the cells that produce it). Other interleukins display more systematic endocrine effects (e.g. some activities of IL-1). 

The signal transduction mechanisms by which most interleukins prompt their biological response are understood, in outline at least. In many cases, interleukin cell surface receptor binding is associated with intracellular tyrosine phosphorylation events. In other cases, serine and threonine residues of specific intracellular substrates are also phosphorylated. For some interleukins, 

Pharmaceutical biotechnology concepts and applications Gary Walsh 2007 John Wiley Sons, Ltd ISBN 978 0 470 01244 4 (HB) 978 0 470 01245 1 (PB) 

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CYTOKINES INTERLEUKINS AND TUMOUR NECROSIS FACTOR Table 5.5. The range of cells capable of producing IL-1... 

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