31
"incomplete" immunomagnetic separations or remixing
experiments as diagrammed in Figs. 2-6 and 2-7. This was
done to determine if new A2B5(+) cells would appear if only
some of the A2B5(+) cells were removed, and also to
determine if appearance of new A2B5(+) cells in purified
cultures could be suppressed by adding back the cells that
were removed. The results of the incomplete separations are
shown in Fig.2-6. The abscissa is the percent cells
incubated in A2B5 before separation which is in effect the
percent of A2B5(+) cells removed, since the remaining cells
had not been exposed to the monoclonal antibody. The
ordinate expresses the percent of the known A2B5(-)/DiO(+)
cells that became A2B5(+) after one day in culture. It can
be clearly seen that the result of removing increasing
numbers of A2B5(+) cells was increasing recruitment of
A2B5(-) cells to become A2B5(+). Thus the increase of
A2B5(+) cells in purified cultures was in direct response
to the depletion of A2B5(+) cells.
Fig.2-7 shows the lack of effect of mixing back those
cells that were removed with purified cells on the
recruitment of newly appeared A2B5(+) cells. Here, complete
separations were performed and the purified A2B5(-) cells
were incubated in dye before remixing with cells recovered
from the microspheres. It is clear that mixing back those
cells that were removed had no effect on decreasing the
amount of newly appeared A2B5(+) cells from those that were