CD4 ENUMERATION (REFRIGERATOR AIDS)
hhscdc!reb4/O=CDC/OU=CINC/OU=NIOBBS1@mhs.attmail.com
21 Dec 92 13:01:22 GMT
I forwarded the request re:CD4 enumeration and refrigeration to my colleagues
Bob Vogt and JAn Nicholson at CDC Atlanta and Jan Nicholson sent this reply:
1) The phemonenon with decreased CD4 cells and refrigeration (refrigerator
AIDS) has not been carefully examined and documented to my knowledge. My
impression is that the density of the cells change, not the expression of the
CD4 receptor. That is because this phenomenon is only seen when the blood is
separated by ficoll-hypaque. If whole blood is kept in the refrigerator,
then labeled and the red cells lysed, usually there is no problem with
detecting the right number of CD4 cells. There is no reason to believe that
the CD4 receptor itself changes because it seems to act as most other
receptors with regards to effects of temperature. Most of the processing
data is anecdotal, with our lab as well as others having looked at
temperature and detection of lymphocyte subsets.
2) and 3) A number of labs have used frozen cells for immunophenotyping
lymphocytes. Our publication is in The Journal of Immunological Methods,
vol. 73, pages 29-40, 1984. Some important things to remember when freezing
lymphocytes is that the methodology must be the same from sample to sample.
In addition, you will likely take a loss of cells, but by the methods we use,
that loss appears to be across all lymphocyte subsets. If you want to use
the cells for functional assays, you will take a loss of activity, and
depending on the assay, the loss may be quite substantial. We have used
frozen lymphocytes as control cells for immunophenotyping by freezing 200-300
vials from one donor and using 1 vial of cells in each run to be sure the
labeling is the same from day to day. They can also be used as a reagent
control to check the monoclonal antibody reagents (new lots, new vials,
different vendors, etc.). Though many labs are using frozen cells for
various reasons, you may not find many references in the literature,
particularly for immunophenotyping.
Good luck!
Jan Nicholson
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