Selective destruction of photoreceptor cells by anti-opsin antibodies

This article reports that cultured photoreceptor cells are selectively vulnerable to complement-mediated lysis by antiopsin antisera. The study has been carried out using a culture system that permits the growth of embryonic retinal neurons and photoreceptor cells in the absence of glial, pigment epithelial, connective, or endothelial cell contamination. Exposure of these cultures to an antiopsin antiserum in the presence of complement results in the lysis of 85% of the photoreceptor cells, without extensive loss of neurons. Photoreceptor lysis by the antibody is dose-dependent and specific, as demonstrated by the ability to block photoreceptor lysis by preincubation of the antiopsin antiserum with purified rhodopsin. Photoreceptor sensitivity to lysis by these antibodies develops in vitro in parallel with the appearance of immunocytochemically detectable opsin. Multipolar neurons (which do not contain opsin) are not affected by the treatment, as shown by microscopic analysis and determination of neuronal "markers" such as choline acetyltransferase and GABA high affinity uptake. These results show that antiopsin antibodies can cause selective photoreceptor degeneration. Moreover, this in vitro system appears useful as a bioassay to test a variety of possible mechanisms of retinal cell destruction which may be important in vivo. The results suggest also a mechanism for the generation of enriched retinal neuronal cultures by selective lysis of photoreceptor cells.