The T cell-selective IL-2 mutant AIC284 mediates protection in a rat model of Multiple Sclerosis

•AIC284 preferentially activated T cells versus NK cells in the Lewis rat model.•AIC284 treatment increased the numbers of CD4+ regulatory T cells in Lewis rats.•Therapeutic application of AIC284 after the onset of EAE did not protect Lewis rats.•EAE was inhibited by AIC284 when administered directly after disease induction.

Targeting regulatory T cells (Treg cells) with interleukin-2 (IL-2) constitutes a novel therapeutic approach for autoimmunity. As anti-cancer therapy with IL-2 has revealed substantial toxicities a mutated human IL-2 molecule, termed AIC284 (formerly BAY 50-4798), has been developed to reduce these side effects. To assess whether AIC284 is efficacious in autoimmunity, we studied its therapeutic potential in an animal model for Multiple Sclerosis. Treatment of Lewis rats with AIC284 increased Treg cell numbers and protected the rats from Experimental Autoimmune Encephalomyelitis (EAE). AIC284 might, thus, also efficiently prevent progression of autoimmune diseases in humans.