90
cultures. These may have been the small number of
NF(+)/A2B5(-) neurons that were detected in the initially
purified cells (see above). The A2B5(+) cells in purified
(long-term) monolayer cultures with nonneuronal morphology
reacted with the monoclonal antibody 5A11. This antibody is
known to be specific for glia in retina (Linser and
Perkins, 1987b) and similarly reacted only with the
surfaces of A2B5(-) glia in the cultures of unpurified
optic tectum cells (Fig.3-4). Purified monolayer cultures
contained many 5A11(+) round cells. These were presumably
the A2B5(+) round cells seen in duplicate cultures, but
double-label analysis could not be performed because both
A2B5 and 5A11 are an IgM. Thus the A2B5(+) cells in
purified cultures not only developed a nonneuronal
morphology in culture but expressed a surface antigen
(5A11) that normally seems to be restricted to glia.
Intermediate Filament Expression In Vitro
Two types of intermediate filaments were investigated
in cultures of unpurified and purified optic tectum cells.
Glial filament expression was examined with both a
commercial polyclonal antibody against bovine glial
fibrillary acidic protein (GFAP) and monoclonal A5 (Debus
et al., 1983). A5 did not react with anything in our
cultures and so the following results are from using the
commercial polyclonal antibody. In unpurified monolayer
cultures GFAP reactivity was confined to the A2B5(-) flat