Kirstine Borum

Influence of neonatal thymectomy upon the cell-mediated tumor-specific immunity in Rous sarcoma virus tumorigenesis in rats

Abstract The effects of neonatal thymectomy upon the output of thoracic duct lymphocytes (TDL), the yield of lymph node cells (LNC) and the cell-mediated immunity to the Rous-specific tumor-associated transplantation antigen(s) were studied in W Fu rats, inoculated with the Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) at four weeks of age. Thymectomy diminished markedly the hourly TDL output, while the effect upon the total LNC yield was not significant. Cell-mediated immunity, registered by means of the colony inhibition technique, could be demonstrated both with TDL and with LNC with fairly good parallellity. In rats without palpable sarcomas and those carrying small tumors, respectively, cell-mediated immunity could be demonstrated in about the same frequency (around 50%) in thymectomized as in sham-operated rats, while in rats with large tumors a lower fraction of thymectomized animals disclosed such an immunity in comparison to sham-operated ones. The results indicate that neonatal thymectomy does not prevent the development of cell-mediated immunity to the Rous-specific tumor-associated transplantation antigen(s).