DEVELOPMENTAL-STUDY OF MULLER CELLS IN THE RAT RETINA USING A NEW MONOCLONAL-ANTIBODY, RT10F7

We produced the monoclonal antibody RT10F7, characterized its antigeni c specificity and expression in the adult and developing retina, in cu ltured retinal cells and in other parts of the central nervous system. In metabolically-labelled retinal cultures RT10F7 immunoprecipitated a protein of approximately 36,000 mol. wt. In the adult, RT10F7 staine d endfeet of Muller cells in the ganglion cell layer, four horizontal bands in the inner plexiform layer, and radial fibres in the outer ple xiform layer which terminated at the outer limiting membrane. In the i nner nuclear layer, most somata were underlined by Muller processes th at wrapped around them, but some cell bodies were immunoreactive for R T10F7 in the cytoplasm. During development, postnatal day 21 was the f irst age at which the adult pattern of immunoreactivity was present, a lthough a fourth band in the inner plexiform layer was less clear than for the adult. By 14 and eight days after birth, the pattern of RT10F 7 immunoreactivity approximated that of the adult; however, only three bands and one band were present, respectively, in the inner plexiform layer. At earlier ages, postnatal days 4, 1 and embryonic ages 19 and 15, the monoclonal antibody stained Muller cell endfeet and radial fi bres, from the inner plexiform layer through the neuroblastic layer to the outer limiting membrane. At these ages, the immunoreactivity was more prominent at the level of Muller cell endfeet. The monoclonal ant ibody stained glia in preparations of dissociated retinal cells mainta ined in culture but not astrocytes or oligodendrocytes from optic nerv e cultures. In brain sections, tanycytes exhibited RT10F7 immunoreacti vity. The monoclonal antibody RT10F7 recognized a specific cell type i n the retina, the Muller cell. In the adult and developing retina, RT1 0F7 recognized an antigen that is present primarily in Muller cell pro cesses. This feature allowed us to follow the maturation of the Muller cell and correlate it with developmental events in the retina. RT10F7 is a specific marker for Muller cells in vivo and in vitro and may be useful for studies of function of Muller cells after ablation or afte r injuries that are known to activate Muller cells. (C) 1998 IBRO. Pub lished by Elsevier Science Ltd.