CX3CR1 and retinitis pigmentosa: Previous studies using injections of recombinant IL-1ra, an endogenous antagonist for IL-1r1, have suggested a role for IL-1β in propagating retinal degeneration, using models of photo-oxidative damage in Cx3cr1-deficient mice [23, 30], laser-induced CNV [24], and retinitis pigmentosa [25].