steric hindrance?

Tom McHugh mchugh at
Thu Sep 21 15:05:24 EST 2000

With 3-color we see significant reductions in staining intensity in the
PE-Cy5 or PerCP-Cy5 signal (FL3) when there is also a strong PE signal. I
assume this is steric hindrance. The antibody combinations of "kappa FITC,
lambda PE and CD19 PE-Cy5 or PerCP-Cy5" and "CD10 FITC, CD34 PE and CD45
PE-Cy5 or PerCP-Cy5" show this reduction in the staining in FL3. We see this
from different vendors and with a high % of samples which have the right
antigen mix. Diluting the antibodies does not help eliminate this problem.
Are others having this problem? Any practical suggestions as to how to avoid

Thomas M. McHugh
Technical Director, Clinical Laboratories
UCSF Medical Center
mchugh at

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