[Genetic engineering of cytokine system on the tuberculosis research]

Murine IL-5 is an acidic glycoprotein with a molecular mass of 40 to 50 kda that consists of homodimer of which monomer comprises 113 amino acid residues. Murine IL-5 has pleiotropic activities on various target cells. IL-5 acts on committed B cells to induce differentiation into Ig-producing cells and on common progenitors for Ly-1+ pre-B cells and Ly-1+ macrophages to support their growth. It also supports growth and/or differentiation of eosinophil precursor and mature eosinophil. IL-5 specifically binds to its receptor (IL-5R) with high and low affinity. IL-5 signals appears to be transduced through the high affinity IL-5R that is composed of two different polypeptide chains; alpha chain and beta chain. The IL-5R alpha chain cDNA encodes p60 that binds IL-5 with low affinity. The IL-5R beta chain, p130/p140 does not bind IL-5 by itself, but binds to alpha chain/IL-5 complex to convert them to the high affinity IL-5R. The beta chain was identified as the IL-3R homologue, AIC2B. Both alpha and beta chain of IL-5R belong to a cytokine receptor superfamily.