immunohistochemistry question

[Amy E. Loercher]

	Howdy all--

	We've been looking at cytokine production in peritoneal exudate 
cells by immunohistochemistry, and we've been seeing some cells stain 
positive for the presence of  certain cytokines, even though the specimen 
is negative for that cytokine transcript by RT-PCR. We think we're 
detecting cytokine that has bound to the cell's surface, but is not 
produced by the cell. R&D, the company that produces the MAb we're using, 
has said this is a possibility. Does anybody know a way to control for 
this? Right now, I'm thinking about either trypsinizing the cells prior 
to fixing to remove everything from the surface, or maybe running a 
sample without saponin and comparing the intensity of staining. Is there 
any reason why either of these would be better than the other? Thanks in 
advance.

Amy Loercher
Dept of Gyn Oncology
MD Anderson Cancer Center