Effect of reticuloendothelial system stimulation on resistance to Rous sarcoma virus infection in chicks

By using a non-toxic reticuloendothelial system stimulant, lipid-Restim, derived from shark livers, we were able to demonstrate the following effects on growing Rous sarcoma tumors in young chicks. Prechallenge Restim treatment: Significant reduction of the percentage of chicks with tumors and prolongation of the latent period resulted from combined administration of Restim and specific antiserum. Postchallenge Restim treatment: The mortality data indicated that there was a significant increase in survival time and survival rate. Complete regressions

1 The term “regression” is used in this paper to mean complete macroscopical disappearance of the primary tumor at the site of inoculation of the virus.

occurred in a significant number of the Restim-treated chicks compared to the controls. Possible explanations of these findings are discussed.