Are you using saponin in the buffer, if not, you may not be successful.  

>Date: Mon, 18 Dec 2000 11:38:59 +0000
>From: Colin Murray <c.murray@dental.gla.ac.uk>
>Subject: Immunohistochemistry IL-18 R
>To: HistoNet Server <histonet@pathology.swmed.edu>
>
>Dear All,
>
>Does anyone have any experience of immunohistochemistry (IHC) staining with
>antibodies to interleukin-18 Receptor?  We have been trying out one
>commercial monoclonal antibody to IL-18R (from R&D) on both frozen and
>paraffin embedded tissue sections/ cytopreps without any luck (employing a
>variety of enzyme systems- citrate/trypsin/protease/EDTA).
>
>Are there any antibodies available on the market that are succesfull in IHC?
>
>Regards
>
>Colin
>  
>
>
>
Gayle Callis
Veterinary Molecular Biology
Montana State University
Bozeman MT 59717-3610
406 994-4705
406 994-4303