Substantially pure human retinal progenitor, forebrain progenitor, and retinal pigment epithelium cell cultures and methods of making the same

A method for generating a cell culture comprising a population of cells wherein at least 90% of the cells in the population are human retinal pigment epithelium (RPE) cells, comprising culturing a population of floating retinal progenitor cell (RPC) neurospheres, wherein the RPC neurospheres have a vesicular morphology and include a hollow center and an outer ringlike laminar layer comprising human retinal progenitor cells oriented radially outwards relative to the neurosphere center, and wherein the outer ring-like laminar layer appears phase-bright and golden in color when observed using bright-field microscopy, identifying a plurality of pigmented neurospheres within the population, and isolating the plurality of pigmented neurospheres from the population into a composition to obtain a cell culture comprising RPE neurospheres comprising a population of cells wherein at least 90% of the cells in the population are RPE cells, wherein the RPE cells comprise the genetic background of a subject having a retinal degenerative disease.