Cell-mediated and humoral immune responses to tumor-associated and viral antigens in relation to the pathogenic effect of Rous sarcoma virus in rats.

Abstract

AbstractAfter inoculation of the Schmidt‐Ruppin strain of Rous sarcoma virus (SR‐RSV) into a series of newborn rats (strain R/F) sarcomas developed in 47% of the animals, half of which also had hemorrhagic‐cystic lesions. In 18% such hemorrhagic cysts occurred without demonstrable tumors, while no pathogenic effect of the virus was observed in the rest of the animals.The colony inhibition technique was used to detect lymph‐node cell (LNC)‐mediated and humoral immunity to the tumor‐associated transplantation antigen (s). LNC‐mediated immunity could be demonstrated in a high proportion of tumor‐positive as well as tumor‐negative rats (83 and 94%, respectively), while the rats with hemorrhagic‐cystic lesions showed such immunity in a lower frequency (56%). Humoral cytotoxic activity could be demonstrated in a higher frequency in rats with cystic lesions than in rats without cysts, whether they had tumors or not (about 80 and 55%, respectively). Antiviral immune response was demonstrable in only a few animals.The results indicate that, as in several other systems, the development of tumors is not related to a deficient LNC‐mediated immune response to the tumor‐associated transplantation antigen (s). Nor could any difference be demonstrated in the frequency of humoral immune response to the antigen (s) between tumor‐positive and tumor‐negative animals. The results furthermore indicate that the hemorrhagic‐cystic lesions, characteristic for the RSV effect, develop in animals which have a less efficient LNC‐mediated immune response and that these lesions are of importance for the sustaining of humoral cytotoxic immune response.