The purpose of the present invention is to provide a novel IL-2 variant that has an improved selectivity for IL-2Raß? and selectively activates Treg. The present invention pertains to: an IL-2 variant； a method for producing the IL-2 variant； a composition containing the IL-2 variant； a therapeutic agent for an immunological disease containing the IL-2 variant； a method for elevating the selectivity of IL-2 for IL-2Raß?； a method for improving the affinity of IL-2 for IL-2Ra subunit； a method for lowering the affinity of IL-2 for IL-2Rß and/or ? subunits； and a method for selectively activating a regulatory T cell.
