48
Table 2-2) and all of these cells in both cultures were
A2B5(-). See Fig. 2-11 for examples of labelled nuclei.
Similarly, long-term (1-2 weeks) monolayer cultures
were subjected to continuous labelling with 3H-thymidine
followed by A2B5 immunostaining and autoradiography. The
A2B5(+) neurons that developed in both purified and
unpurified cultures did not contain labelled nuclei (Fig.2-
11). Out of several hundred neurons examined where cell
bodies could be clearly seen not one contained a labelled
nucleus. The majority of A2B5(-) flat cells, however, had
densely labelled nuclei. These nuclei were rather large in
diameter, quite flat, and oval shaped.
Discussion
A diagrammatic summary of the results is presented in
Fig.2-12. I have developed a method for the purification of
dissociated embryonic brain cells based on the removal of a
target cell population by specific antibody linkages to
paramagnetic microspheres. This method was developed to
purify embryonic glia so that phenomena such as the
induction of GS by neurons could be studied in vitro in a
controlled fashion. The cell isolation experiments in
methylcellulose demonstrated that embryonic tectum cells
could be manipulated for a significant length of time (2
days) before they lost competence for GS production when
reaggregated. Thus it seemed entirely possible to develop a
method of separation that would be useful within this time