| Popis: |
We have derived a cell line from an epiretinal membrane excised surgically from a premature female infant born at a gestational age of 25 weeks, and who developed stage 5 retinopathy of prematurity. The cell line, which in early passages appeared immunocytochemically to contain cells with both neuronal and glial characteristics, has been maintained in culture for 14 months at the time this manuscript was submitted, and has survived 20 passages. The cells have a diploid, human karyotype, with most cells possessing 46 normal appearing chromosomes, including 44 autosomes and two X-chromosomes. Morphologically, the cell line at early passages consisted of polygonal cells and also of cells possessing long, spindly branching processes. These two cell types were cloned. Nearly 100% of the cells of both morphologic types in mixed cultures stained immunocytochemically for neuron-specific enolase (NSE), a neuronal marker, and approximately 5-10% of the cells in mixed cultures (including about 50% of the cells with the spindly morphology, that were less prevalent in mixed cultures) stained for glial fibrillary acid protein (GFAP), a glial marker. We have not performed "double-label" immunocytochemistry, but it was evident from the proportion of cells that stained with each marker that many cells must contain both GFAP and NSE. At least 50% of the cells in most of the early cultures were positive for keratin, while all were (and remain) negative for muscle actin. No cells are found that are immunocytochemically positive for factor VIII, a vascular endothelial cell marker. These cultured cells have also been studied immunocytochemically for their production of extracellular matrix substances. The cultures are immunocytochemically positive for type IV (but not type I) collagen, laminin and fibronectin. In later passages, cells of both clones lost their immunocytochemical positivity for GFAP and NSE, and all became positive for keratin. Cells of both clones also developed a similar, polygonal morphology, lacking long processes. By electron microscopy, many of the cells were seen to possess nonmotile cilia, with a 9 + 0 pattern of microtubule doublets. This cell line may be useful for studies of human retinal cell development and metabolism, and responses to pathological processes. |
