Leu 7 immunoreactivity in fetal olfactory epithelium and dysplastic or neoplastic olfactory lesions induced in Syrian golden hamsters by N-nitrosodiethylamine.

The biotinylated monoclonal IgM antibody, anti-Leu 7 (HNK-1) was used to localize, by 2-step avidin-biotin immunocytochemistry, an antigen that appears in olfactory nasal epithelium of male Syrian Golden hamsters during N-nitrosodiethylamine (DEN) carcinogenesis. In normal young adult and adult hamsters, Leu 7 was not immunoreactive with nasal olfactory epithelium. In hamsters that had been given multiple doses of DEN, Leu 7 immunoreactivity was found throughout the olfactory epithelium. The carcinogen produced dysplastic and hyperplastic lesions in the olfactory epithelium as well as carcinoma in situ and poorly differentiated carcinomas, occasionally with rosette-like structures, all of which were immunoreactive with the Leu 7 monoclonal antibody. Other preneoplastic lesions and tumors (adenomas of nasal glands, papillomas, adenocarcinomas) in olfactory and respiratory nasal epithelium were never immunoreactive. Hamster fetuses expressed Leu 7 diffusely on olfactory epithelial cell membranes, neonatal hamsters had much less antigen, and 14- and 28-day-old hamsters contained few immunoreactive cells. Thus, evidence was provided that Leu 7 reacts with a fetal olfactory antigen which reappears during stages of chemically induced nasal carcinogenesis in Syrian Golden hamsters.