Abstract
Summary
In the microcytotoxicity assay, a stimulatory effect exerted by nonsensitized spleen cells derived from nude mice was observed on the growth of tumorigeneic human tumor cells. In contrast, the growth of non-tumor-producing cell lines (malignant and nonmalignant) was inhibited by identical effector cells. Two out of four non-tumor-producing cell lines were of malignant origin. This lack of tumorigenicity, despite a derivation from tumor tissue, might be due to a selection of stromal cells during cultivation or might reflect a variation in the sensitivity to natural cytotoxicity independent of malignancy vs nonmalignancy. Consequently, lack of tumorigenicity does not exclude the possibility that the cells are malignant.
The technical assistance of Vibeke Ahrenkiel is gratefully acknowledged. I thank Lone Atke for careful secretarial assistance. This work was supported by Danish Medical Research Council Grants 512–5274 and 512-3547.
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