The fibroblasts that are overgrowing your fusion plates are coming from
the mouse's spleen. I have seen this problem when I have tryed to
disperse the lymphocytes from the spleen too vigorously. It will also
tend to happen more when the mouse is old than when using a younger mouse.
My suggestions would be that you disperse the lymphocytes from the spleen
less vigorously and something that I routinely do is once I have ground up
the spleen, I aspirate the cell suspension into a conical polyethylene
centrifuge tube and let the heavy stuff settle out (About 10-15 min). The
fibroblasts will tend to stick to the tube so that I don't see this
overgrowth problem.
Macrophages don't divide and overgrow the fusion plates like fibroblasts
do. I used to use macrophages all the time as feeder cells for the
hybridomas without any problems.
Hope this helps,
Bradley Bone
COR Therapeutics, Inc
