dot blots

[John Ferbas]

I am naively attempting to perform an HIV p24 dot blot, with limited 
success.  For now, I am using lysates from cell cultures infected with
HIVNL4-3.  I cannot achieve a uniform dot -- rather, I typically see a 
halo\ring pattern.  Otherwise, I can distinguish between positive and
negative lysates. I am using a biorad apparatus according to thier 
instructions, and I am interested in techniques that might eliminate
my unusual blotting pattern.  In particular, I wonder whether a larger
pore size might help (I am using 0.2micron).  Thanks in advance for
any helpful hints.
John Ferbas, Ph.D.
UCLA