TEMPORAL ANALYSIS OF CELLULAR CYTOTOXICITY AND HUMORAL FACTORS DURING PROGRESSION AND REGRESSION OF ROUS SARCOMAS IN JAPANESE QUAILS

Abstract
Temporal appearance of cellular cytotoxicity and humoral activities including blocking and arming activities during the entire course of Rous sarcoma development in Japanese quails was examined by a microcytotoxicity assay with comparison of animals bearing regressing tumors induced by a moderate dose of virus (regressors) and animals bearing growing tumors induced by a large dose of virus (progressors). Cellular cytotoxicity of spleen cells in regressors was detected in a biphasic pattern, the 1st phase being observed as early as 3-5 days post inoculation (p.i.), followed by an eclipse period 7-10 days p.i. which was the time of active tumor growth, and the 2nd phase occurring after 12 days p.i. when the tumor attained maximum size. In progressors, only the 1st phase was observed. A stimulatory effect of the spleen cells on growth of target cells was noticed. Arming activity which confers cytotoxic activity on normal spleen cells was demonstrated in the sera of regressors in the similar biphasic pattern as the cellular cytotoxicity, early activity being present at 3 days p.i., and late activity after 19 days p.i. The former was detected by preincubation with target cells. In progressors, only early arming activity which reacts with effector cells was demonstrated. Blocking activity which abrogates cellular cytotoxicity was demonstrated in regressors and progressors but in different patterns of appearance, i.e., blocking activity in regressors was only transiently demonstrated only by preincubation with effector cells at the time of maximum tumor growth, while activity in progressors seemed to persist after the tumor reached maximum size. Since earlier activity was effective at effector cell level, and the later activity at effector and target cell levels, participation of blocking factors of different types in progressors was also suggested.