Looking for a better way to detect IgM secreting cells

Dear colleagues,

For brevity's sake let me pose the question first, then I'll write the
background below so as not to force you all to read a long winded
explanation before the point of the email: Is there a technique for
rapidly, accurately, and cheaply measuring cell concentration and
viability that requires only a small number of cells?

In our lab we are interested in measuring impairment of mature B
lymphocyte differentiation into antibody secreting plasma cells. One
of my fellow graduate students is using human B lymphocytes, and at
this point has a reasonably good system for stimulating their
differentiation into plasma cells. One of the more difficult
limitations we have is that there are relatively few cells at the end
of the experiment. Typically we will use a portion of the cells for an
IgM ELISPOT and some for cell count and viability determination using
a Coulter Counter Z1 (which requires about 1/3 of the cells just to
get cell number and viability). We then normalize the number of IgM
secreting cells to the number of viable cells to derive the number of
IgM secreting cells per 10^6 viable cells.

If we could find a way to measure cell number without using quite so
many cells then we could use some of the cells for RNA isolation,
something we really want to be able to do. A hemacytometer is not a
viable option because it is not rapid enough. We do have access to a
FACSCalibur, but I haven't heard anyone using it to simply measure the
concentration of cells present in a sample.

Sincerely,
Colin M. North


PhD Candidate
Michigan State University
Department of Pharmacology & Toxicology
http://www.phmtox.msu.edu/people/gradstudents/northprint.html