Double CD4 and CD8 staining of blasts in culture

From: Da Silva, Marcos (Marcos.DaSilva@umassmed.edu)
Date: Mon Dec 11 2000 - 16:40:34 EST


Colleagues,

I've been working for the last months in developing a system to evaluate
proliferation of human T lymphocytes in response to different antigens and
mitogens. I am using CFSE as the proliferation marker, and CD3 (APC), CD4
(PE) and CD8 (Cy-chrome) as the fluorescent conjugates. I've been concerned
with the fact that, after 5-7 days in culture, the blast population usually
presents with 10 to 20 percent of CD3 cells that stain positively both for
CD4 and CD8. This does not happen when I gate and analyze the small lymphos.
It does not seem to make sense, comparing to the "in vivo" lymphocyte
proliferation. Would it be an artifact of cultured rapidly proliferating
cells?  Could it be due to Fc-receptor binding of the fluorochromes, with my
blocking (with AB serum) being inneficient?

Thank you,

Marcos da Silva
Pediatric Immunology lab
University of Massachusetts Medical School - Worcester - MA - USA
e-mail: Marcos.DaSilva@umassmed.edu



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