Muramyl dipeptide (MDP) and mouse recombinant IL-1β were purchased commercially (Bachem, Torrance, CA and R&D Systems, Minneapolis, MN, respectively). IL-1Ra, IL-1α, and IL-1β protein levels were measured in whole eye homogenates using commercially available ELISA kits (R&D Systems) as per manufacturer’s instructions and previously reported (16 (link)).