DISTRIBUTION OF TRANSFORMING GROWTH-FACTOR-BETA ISOFORMS IN THE MAMMALIAN RETINA

The distribution of transforming growth factor-beta (TGF-beta) was exa mined in the posterior segment of the monkey, human, and feline eye us ing antisera to TGF-beta 1, TGF-beta 2, or TGF-beta 3. A number of dif ferent antibodies, tissue processing methods, immunolocalization techn iques, and microscopic imaging systems were used in an attempt to gain a more comprehensive picture of TGF-beta isoform distribution in the retina and retinal pigmented epithelium (RPE), The results are general ly consistent in identifying one or more of the three TGF-beta isoform s in the cytoplasm of a small, overlapping subset of cells, RPE cells, photoreceptors, Mueller cells, ganglion cells, hyalocytes, and cells associated with choroidal and retinal vessels are all represented in t his immunoreactive population, No evidence of extracellular labeling w as noted, The intracellular distribution of the three isoforms is dist inctly different in photoreceptors. Anti-TGF-beta 1 precursor and anti -TGF-beta 2 immunoreactivity is confined primarily to rod outer segmen ts, whereas anti-TGF-beta 3 immunoreactivities are restricted to mitoc hondria within inner segments, In the RPE, dusters of anti-TGF-beta 2 positive cytoplasmic granules are located near the cells' lateral bord ers, whereas anti-TGF-beta 3 labeling is concentrated apically. These results provide baseline information from which new hypotheses regardi ng the function(s) of TGF-beta isoforms in the retina can be formulate d. (C) 1995 Wiley-Liss, Inc.