Abstract
Spleen cells from random-bred chickens bearing Rous sarcomas were commonly more reactive against the neoplastic target cells in autochthonous than in allogenic interactions in vitro. This difference was observed both in cytotoxic assays ((51)Cr release from labeled target cells) and in an immunoadherence test measuring attachment of (51)Cr-labeled splenocytes to Rous sarcoma cells. Specific splenocyte reactivity was not observed with normal embryonic chicken fibroblasts, 3T3 cells, or embryonic mouse C3H fibroblasts. The immunoadherence technique required only 2 hr to perform, and revealed a more consistent superiority of autochthonous recognition of Rous sarcoma cells than the cytotoxicity assay. Experiments in which both procedures were used simultaneously with identical cell populations yielded similar results, indicating that splenocyte adherence may be a precursor of and/or concomitant to target cell damage and that individual-specific tumor antigencity may play a part in cellular immunity against Rous sarcomas.