A comparison of six monoclonal antibodies for detection of cytokeratins in normal and neoplastic canine tissues

Veterinary Medical Teaching Hospital, University of California, Davis 95616.

Twenty normal canine tissue specimens, both fetal and adult; 19 epithelial neoplasms; and 18 nonepithelial neoplasms were examined using 6 commercially available monoclonal antibodies differing in their recognition of various molecular weight cytokeratins in human tissues. Fresh tissue samples were fixed in 100% ethanol and paraffin embedded prior to sectioning. The intermediate filament proteins were identified by an avidin-biotin-immunoperoxidase method. Primary antisera used included AE1/AE3, CAM-5.2, 35BH11, 34BE12, PKK1, MAK-6 cytokeratins, and vimentin. Monoclonal antibodies detected cytokeratins in a wide variety of canine epithelial tissues and neoplasms. Normal mesenchymal tissues and neoplasms, and stromal elements of epithelial tissues, showed no reactivity with anti-cytokeratins, but reacted positively with vimentin. Although PKK1, CAM-5.2, and MAK-6 were the most consistently reactive anti-cytokeratins, the full panel of monoclonals was required to detect cytokeratins in all of the epithelia evaluated.