CNTF and retinal degeneration: In the present study, we have evaluated the neuroprotective effects of a sustained neural stem cell-based intraocular administration of ciliary neurotrophic factor (CNTF), a member of the interleukin-6 family of cytokines [30] that has been shown to potently rescue retinal structure in various animal models of retinal degeneration [26, 28], on photoreceptor cells in the nclf mouse.