Description
Il23a isa heterodimeric cytokine composed of two disulfide-linked subunits, a p19subunit that is unique to Il23a, and a p40 subunit that is shared with IL-12.The Il23a homology to the p35 subunit of IL-12, as well as to other singlechain cytokines such as IL-6 and IL-11. The p40 subunit is homologous to theextracellular domains of the hematopoietic cytokine receptors. Mouse p19 cDNAencodes a 196 amino acid residue (aa) precursor protein with a putative 19 aasignal peptide and 177 aa mature protein. Human and mouse Il23a share 70% aasequence identity. Although p19 is expressed by activated macrophages,dendritic cells, T cells, and endothelial cells, only activated macrophagesand dendritic cells express p40 concurrently to produce Il23a