Cellular immunity and its serum‐mediated inhibition in shope‐virus‐induced rabbit papillomas

Abstract

Abstract A colony‐inhibition technique was used to demonstrate lymph‐node‐cell (LNC) mediated immune reactions against tumor‐specific transplantation antigens of Shope‐virus‐induced papilloma and carcinoma cells. Lymph‐node cells from rabbits in which Shope papillomas had regressed spontaneously, as well as LNC from rabbits with persistent Shope papillomas, reduced the plating efficiency of Shope‐virus‐induced papilloma and carcinoma cells but did not affect normal skin fibroblasts from the same rabbits as the tumor cells. Serum from rabbits with persistent Shope papillomas or Shope carcinomas abrogated the inhibitory effect of regressor LNC on Shope tumor cells, while serum from regressor rabbits had no such effect. It is postulated that sera from “persistor” and carcinoma rabbits contain antibodies which mediate an efferent form of immunological enhancement.