The most commonly used method to measure CMC/ADCC is a
radioactive chrominum-51 (51Cr)
release assays (2). There are several disadvantages with
this assay: it is expensive, difficult to load certain cell
types, expensive to dispose of due to strict environmental
regulations, and has high background from spontaneous
release of 51Cr. With
the use of flow cytometry, it is now possible to eliminate
the need for radioactive material and increase the ability
to quantify cytolytic activity on a single cell bases.
Various groups have demonstrated that measuring CMC/ADCC
activity by flow cytometry has a strong (95%) correlation
with the traditional 51Cr
release assay (3,4,5,6).