Low-affinity MAbs in flow cytometry?

[John Ladasky]

Greetings, fellow colleagues (my, doesn't that sound pompous),

	I was just wondering.  If you had an antibody that bound an
epitope on a cell, but the affinity of that binding was not so high,
what would you expect to see on a flow cytometer?  I got into a debate
with someone at a recent lab meeting about this issue.  One of my 
*real* fellow colleagues thinks that a cell with a low-affinity epitope
for a given MAb would show a decreased *level* of staining when com-
pared to a cell with the same number of binding sites, but a higher 
affinity.  I say that, using a "normal" antibody titer, and washing
the sample several times before analysis, a low-affinity binding would
exhibit either saturating fluorescence or no fluorescence.  My reason-
ing is that the half hour or so between staining and analysis, plus the
wash steps, should be adequate to resolve any intermediate levels of
fluorescence.

	Comments?  

-- 
Unique ID : Ladasky, John Joseph Jr.
Title     : BA Biochemistry, U.C. Berkeley, 1989
Location  : Stanford University, Dept. of Structural Biology, Fairchild D-105
Keywords  : immunology, music, running, Green