[Cytokine redundancy--unity in diversity]

Various cytokines can induce similar biological effects in one type of cells (shared biological activity-redundancy). However, particular cytokine can also act on different tissues and cell types (multiple biological activity-pleiotropy). The functional redundancy and pleiotropy might be explained by binding of related cytokines to a common subunit of the receptor that have unique signalling capacity. Specificity of signal transduction is presumably controlled by the intracytoplasmic structure of the subunit chain, the level of activity of cytoplasmic signal molecules as well as combinations of the receptor subunits on the different type of cells.