TdT caveat

Walter Sharp (
Fri, 18 Apr 1997 01:14:04 -0400

Following earlier discussions re: Caltag and, perhaps, tying in to the more
recent TdT neg ALL exchanges we also had an apparently negative T-ALL
(2/cy3/5/7/8/34) the other day.
I say apparent because a repeat of the staining using our in house method
gave a clear (admittedly dim) TdT positive result where the HT6 clone in
Fix & Perm was unequivocally (0%) negative.Both methods were whole blood
using identical concentrations & timings.
The strength of the cytoplasmic CD3 staining was the same by both
techniques so it appears that the nuclear membrane may be a little too
tough for An der Grubb's stuff.
As I said way back when, I have always been suspicious of the strength of
Caltag TdT staining but I didn't expect such a big disagreement between
In future all our TdT staining (tho' not MPO!) will be by our own method -
we just have to sort out the higher autofluorescence seen with AML's after
fixation (must re-read the postings on this).

Since I'm on about TdT, what do other contributors feel about setting the
positive region ?
Matched isotypic, unstained control, TdT staining on normal lymphs or what

Wal Sharp

Home Page Table of Contents Sponsors E-Mail Archive Web Sites

CD-ROM Vol 3 was produced by Monica M. Shively and other staff at the Purdue University Cytometry Laboratories and distributed free of charge as an educational service to the cytometry community. If you have any comments please direct them to Dr. J. Paul Robinson, Professor & Director, PUCL, Purdue University, West Lafayette, IN 47907. Phone: (765)-494-0757; FAX(765) 494-0517; Web , EMAIL