background
Thomas Delohery (t-delohery@ski.mskcc.org)
Fri, 10 Nov 1995 17:10:32 +0530
>Please pause to consider that your assumption about the isotypic control
>is that
>it binds to the cell and produces fluorescence in the same way as your test
>antibody. This assumes that only Fc binding is involved, that Fc binding is
>identical between conjugated antibodies of the same isotype and the
>fluorochrome/protein ratio between the antibodies is exactly the same. It is
>possible that the Fc binding and other nonspecific binding (usually
>hydrophobic
>in nature) are not the same as the isotypic control.
My comments were directed to assays where there is NO non-specific binding
as determined by the appropriate biological controls and. The situation Eric
described, where the entire population is slightly shifted toward the positive,
is common when the surface antigen is at extremely low levels. Using percent
positive to describe such data is inaccurate.
td
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Thomas Delohery | Internet: t-delohery@ski.mskcc.org
Manager, Flow Cytometry Core Facility | Phone: (212) 639-8729
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