Studies on the physiological manifestations of cell-mediated cytotoxicity. I. Early metabolic changes in mouse plasmacytoma cells exposed in vitro to sensitized allogeneic splenocytes

Early and later biochemical changes occurring in neoplastic target cells interacting with sensitized lymphoid cells were investigated, with emphasis on the detection of very early damage to the target cells. The sensitizing and target cells were a BALB/c plasmacytoma; the effector cells were obtained from the spleens of specifically sensitized and normal C57BL mice. The incorporation of labeled glycine and leucine, uridine, and thymidine into macromolecular entities by the plasmacytoma cells was followed as an indication of ability to take up the precursor and/or biosynthetic capacity. Separation of target and attacking cells was effected in some experiments by use of anti-C57BL lymphocyte serum. Amino acid and uridine incorporation were markedly altered between the second and fourth hour of interaction, and specific release of ⁵¹Cr was seen only after 2 hr. In contrast, thymidine incorporation was inhibited almost immediately after contact; this inhibition was shown to occur in PCT cells incubated at various ratios with sensitized spleen cells.