Identification of the blue-sensitive cones in the mammalian retina by anti-visual pigment antibody.

Monoclonal antibodies to visual pigments produced in our laboratory were applied to analyze the distribution of color-specific photoreceptor cells in the retina (photoreceptor mosaic). We demonstrated in two ways that the monoclonal antibody OS-2 specifically recognized the blue-sensitive cone cells in the mammalian retina. First, rabbit photoreceptors damaged selectively by intense blue light were recognized by OS-2 antibody. Second, OS-2-positive cones in the ground squirrel were those with thick inner segments, which is known to be characteristic of the blue-sensitive cones. In addition, the OS-2-positive cones in monkeys have a distribution and pattern characteristic of blue-sensitive cones in that species. In several other species (human, rabbit, cow, and pig), the OS-2-positive cones represent an appropriate minority of the population of photoreceptor cells. The visual pigment recognized by the OS-2 antibody had a relative molecular weight of 36,000, as shown by immunoblotting of 3 mammalian species. All other cones were recognized by another monoclonal antibody, COS-1, which is regarded as specific to middle-to-long-wavelength-sensitive photoreceptors.