IMMUNOHISTOCHEMICAL DETECTION OF THE TYPE-I INTERFERON RECEPTOR IN HUMAN FETAL, ADULT, AND NEOPLASTIC TISSUES

We have used the monoclonal antibody IFNaR3 that recognizes the alpha subunit of the type I interferon (IFN) receptor to study the expressio n of this receptor in a large series of normal human adult and fetal t issues, as well as in a large number of tumors of diverse origin. Amon g fetal tissues (8-20 weeks) the type I IFN receptor was expressed in liver, striated muscle, epidermis, renal tubules, choroid plexus of th e CNS, and epithelia of different origins (bronchial, gastrointestinal , and pancreatic). Adult tissues showed a similar pattern that include s epithelia from salivary ducts, genital tract, bladder, breast, as we ll as germinal centers of lymph nodes, tonsils, and spleen. The study of a large series of tumors revealed;that the type I IFN receptor is e xpressed in most, but not all, melanomas, bladder, kidney, small bowel , lung, and breast adenocarcinomas. The majority of lymphomas, sarcoma s, and endocrine tumors proved negative. These results support the con cept that the type I IFN receptor is rather ubiquitously expressed in normal and malignant epithelial tissues. More interestingly, the expre ssion of the type I IFN receptor was not detected in all tumors, raisi ng the question of whether some cases may fail IFN alpha therapy due t o the lack of receptor expression. This report demonstrates that the I FNaR3 monoclonal antibody can be used for receptor detection in paraff in-embedded sections and it could represent a useful tool in the searc h for correlations between IFN alpha response and receptor expression in different diseases.