Proliferating lymphocytes in peripheral blood and CD25 expression

This exchange took place between Petros Christopoulos and Howard Shapiro


Petros Christopoulos wrote:

>I would like to ask if anybody knows about the relationship of
>expression of classical
>proliferation markers (like Ki-67 or the transferrin receptor) and
>CD25 (which is also an activation marker) in peripheral blood lymphocytes.
>Do they give similar results, do they correlate or are they totally
>independent of each
>other ?

Time to start another winning streak for Mailing List submissions...

See Figure 10-7, p.460, in the 4th Edition of Practical Flow
Cytometry (available without charge on the Invitrogen/Molecular
Probes web site, http://probes.invitrogen.com/) for plots relating
transferrin receptor (CD71) expression and RNA content to DNA
content. I have speculated in the book and on this Mailing List that
Ki-67 and CD71 should correlate almost absolutely in proliferating
lymphocytes and probably in most or all other cell types, but, when I
just looked on PubMed, I could not find any publication suggesting
that both had been measured simultaneously in the same cells at the
same time. This really needs to be done; there have been over 100
papers published referring to Ki-67 in the past year, representing a
lot of work by many people. Detecting Ki-67 requires permeabilization
and is only possible in fixed cells, whereas detecting CD71 requires
only surface staining, meaning that live cells can easily be analyzed
and sorted based on CD71 status, but not based on Ki-67 status. If
the two markers are as well correlated as I suspect, a switch from
Ki-67 to CD71 staining will save both time and money, and, more
importantly, allow researchers to do further functional studies on
live cells precisely characterized as to cell cycle position. Such
studies can, in at least some cases (see the work of Edward Srour et
al), be done using Hoechst 33342/Pyronin Y staining for DNA and RNA,
but pyronin Y can be toxic.

_________________________________________________________

So, my input on this topic is the following. Howard's assumption is right on
the money. expression of CD71 and Ki67 correlate well with one another. we
have isolated murine cells lacking the expression of CD71 versus cells that
are CD71+. upon PCR analysis of these cells, we found that CD71- cells do
not express Ki67 while CD71+ cells do. the separation between CD71+ and
CD71- cells is a little tricky depending on the cell type since many cell
groups present a continuum of CD71 staining such that separation between
positive and negative is rather subjective. As others argued on this forum
that an isotype control is in general useless, this may be a case where the
use of an isotype may be helpful.  we have not published this yet.

Also another point of agreement with Howard. Pyronin Y is toxic especially
to murine cells while it is well tolerated by human cells. unfortunately,
some people are publishing the use of Pyronin Y with murine hematopoietic
cells without recognizing that although the data presented clearly indicate
something wrong was going on in these cells.

Happy Holidays

edward f. srour



Edward F. Srour, Ph.D.
Professor of Medicine, Pediatrics, Micro/Immunol.
Indiana University School of Medicine
Cancer Research Institute
1044 West Walnut Street. R4-202
Indianapolis, IN 46202-5121

Phone: 317-274-0343
	    317-274-3589
Fax:	 317-274-0396
email: esrour@iupui.edu