Effect of injection of adenovirus type 12 in adult hamsters

Large doses of adenovirus type 12 were injected intraperitoneally into adult hamsters, and development of tumors and other pathological findings were studied in comparison with those in hamsters injected when newborn. Doses of 38~47 TCID60 per gram body weight produced tumors in 3 of 12 hamsters injected at 37~57 days of age. A dose of 170 TCID60 per gram body weight produced tumors in one of 18 hamsters injected at 61~71 days of age, but in none of 18 hamsters injected at 147~174 days of age, while the same dose per gram body weight produced tumors in 24 of 26 hamsters injected when newborn. In hamsters injected at adult ages, the number of tumors per animal decreased and the latent period for tumor development became very long as compared with those in hamsters injected when newborn. Regardless of the age at the time of injection, acute inflammatory change was observed in the peritoneum which later developed into various degrees of peritoneal adhesion. Adenovirus type 3 also induced the peritoneal adhesion. Histology of tumors was studied and discussed.