On 13 Feb 2001 23:11:52 -0000, daniela <vuvu at freemail.it> wrote:
>Hi
>is it possible to isolate mouse memory CD4 cells? I saw in a paper that
>the only reliable marker is CD44 but it's just slightly increased in
>memory versus naive; do you know of other markers?
>thanks
>Valeria
CD44 is upregulated quite a bit on memory cells (up to 10-50x) - the
problem is more that memory cells tend to have a broad peak of CD44
expression, making it difficult to resolve the lowest expressers from
naive cells. However, using just biotin-labeled anti-CD44 and commercial
magnetic bead technology, I have gotten pretty good (although not
complete) separation of CD44hi and CD44lo (peaks separated by a log of
fluorescence intensity, but overlapping slightly) CD4 cells from
unmanipulated B6 mice; using FACS, it should be pretty straightforward to
separate these populations by gating on the very high and very low CD44
expressers.
Another good marker for memory vs naive is CD62L (L-selectin), which is
high on naive cells and downregulated on memory (although there is some
evidence that memory cells can re-express it over time)
A double-stain should easily distinguish naive (CD44lo/CD62Lhi) from
memory (CD44hi/CD62Llo) cells.
In my experience, CD45RB is more variable - cells may be CD44hi without
downregulating CD45RB (which is high on naive cells) - but CD45RBlo/CD44hi
would be another way to mark memory cells.
Ken Frauwirth
--
Ken Frauwirth (MiSTie #33025) kfrauwir at mail.med.upenn.edu
Abramson Cancer Research Institute
University of Pennsylvania
http://mail.med.upenn.edu/~kfrauwir
"Science is not the way to find the answers to all of our questions.
Science is a way to find better questions." - C. Barrans