OBSOLETE. Binding to beta subunit of interleukin-18. IL-18b is a ligand non-binding chain and is required for signaling of IL-18 that binds with IL-18a.
OBSOLETE. Binding to alpha subunit of interleukin-18. IL-18a is a component of IL-18 that is essential for IL-18 binding on the surface of T-helper 1 cells.