Interleukin-1 receptor antagonist IL-IRa

The three molecules of the IL-1 family, interleukin-la (IL-la), interleukin-1 3 (IL-ip), and interleukin-1 receptor antagonist (IL-IRa) map to the long arm of chromosome two in the human genome. It appears that the family arose via a gene duplication event some 350 million years ago, and the molecules possess between 27.5 and 36% sequence identity with each other (Table 2) [1,14,15]. In addition, the genes for the two IL-1 receptors IL-1R1 and IL-1RII [16,17], and an IL-1R accessory protein (IL-lRacP), which binds to the IL-1, IL-1 receptor complex [18], have been identified. Together, these molecules via their differential activity serve primarily to modulate the host defense mechanism. 

J. Lin, Y.J. Chang, W.B. Yang, A.L. Yu, and C.-H. Wong, The multifaceted effects of polysaccharides isolated from Dendrobium huoshanense on immune functions with the induction of interleukin-1 receptor antagonist (IL-Ira) in monocytes, PLoS ONE, 9 (4), e94040,2014. 

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