Mike Kastan developed an assay following formaldehyde fix and triton
X-100 permeabilization which he published in blood (Blood 74: 1517,
1989). He used a corrected MFI to quantify, noting that different bone
marrow populations have different FITC avidity when permeabilized. Mike's
technique was strengthened by his controls, which involved preincubating
the antibody with the peptide to which it was raised.
Steve Gore
Johns Hopkins Oncology Center