From EurekAlert!: "A gene therapy approach using a protein called CD59, or protectin, shows promise in slowing the signs of age-related macular degeneration (AMD), according to a new in vivo study ... CD59 delivered by a gene therapy approach significantly reduced the uncontrolled blood vessel growth and cell death typical of AMD, the most common cause of blindness in the elderly. ... Activation of the complement system, a part of the immune system, is responsible for slowly killing cells in the back of the eye, leading to AMD. Activation of this system leads to the generation of pores or holes known as 'membrane attack complex' or MAC in cell membranes. CD59 is known to block the formation of MAC. ... CD59 is unstable and hence previous studies using CD59 have had limited success. The gene therapy approach that we developed continuously produces CD59 in the eye and overcomes these barriers, giving us renewed hope that it can be used to fight the progression of AMD and potentially other diseases. ... [Researchers] delivered CD59 to the eye using a deactivated virus similar to one previously shown to be safe in humans. Using an established mouse model of age-related macular degeneration, they found that eyes treated with CD59 had 62 percent less uncontrolled blood vessel growth and 52 percent less MAC than controls. ... Treatment was effective when administered at a very specific location beneath the retina, but importantly, also when it was administered to the center of the eye. This finding is especially encouraging because it would allow for a safer and more convenient route of administration of treatment."