Interleukin-2 receptor subunit beta (IL2RB) is also known as CD122, which Belongs to the type I cytokine receptor family. Type 4 subfamily. IL2RB contains 1 fibronectin type-III domain. IL2RB / CD122 is involved in T cell-mediated immune responses, is present in 3 forms with respect to ability to bind interleukin 2. The low affinity form is a monomer of the alpha subunit and is not involved in signal transduction. The intermediate affinity form consists of an alpha/beta subunit heterodimer, while the high affinity form consists of an alpha/beta/gamma subunit heterotrimer. Both the intermediate and high affinity forms of the receptor are involved in receptor-mediated endocytosis and transduction of mitogenic signals from interleukin 2.