Copolymer-1 vaccination regimens for neuroprotection in laser-induced retinal injuries

The neuroprotective effect of immunization by glatiramer acetate (Copolymer-1, Cop-1, Copaxone) in adjuvant against laser-induced retinal damage was previously reported. The present study quantitatively compares various regimens of this vaccination for reducing the spread of laser-induced retinal damage and investigates the cellular mechanism of Cop-1 activity. Standard argon laser lesions were created in 78 DA pigmented rats divided into five groups: three Cop-1 single treatment groups (treated 7 days before, immediately after, or 24 hours after the injury), one group treated twice (7 days before and 20 days after injury), and a control group treated with adjuvant 7 days before the injury. The retinal lesions were evaluated 3, 20, and 60 days after the injury. Immunostaining of the retinas of the pretreated and control group animals 3 days after the laser injury was performed for T-cell detection. Cop-1 pre-immunization reduced photoreceptor loss at all time points as measured over the central zone of the lesion and 3 and 20 days after lasing as measured over the whole damaged area. Lesion diameter was reduced only 60 days after laser injury in pre-treated animals. Cop-1 given immediately after injury reduced cell loss as measured 20 and 60 days later in the whole lesion and 20 days after the laser irradiation, when measured in the center of lesion. It had no effect on lesion diameter. Late treatment reduced only the lesion diameter at all time points. Repeated treatment enhanced the neuroprotective effect, decreasing the cell loss in the center of lesion and reducing the diameter of lesion. T-cells were detected in the retinal lesions of pre-immunized animals and not in non-treated group, demonstrating the cellular immune mechanism of Cop-1. Immunization with Cop-1 is neuroprotective against laser-induced retinal injuries, and repeating the treatment enhances this effect. Cellular immune action of Cop-1 of was detected.