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 wherein at least 90% of the cells are human retinal pigment epithelium (RPE) cells, comprising

• culturing a population of floating human vesicular neurospheres in the presence of Activin until pigmented RPE neurospheres form, wherein the human vesicular neurospheres have a hollow center and an outer ring-like 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 RPE neurospheres within the population, and
• isolating the plurality of pigmented RPE neurospheres from the population and introducing the isolated neurospheres into a culture medium to obtain a cell culture comprising pigmented RPE neurospheres wherein at least 90% of the cells in the cell culture comprising pigmented RPE neurospheres are RPE cells.