NK sensitivity of H-ras transfected fibroblasts is transformation- independent

We have examined the hypothesis that NK cells can preferentially recognize fibroblasts transformed by the H-ras oncogene. 10T1/2 fibroblasts were transfected with the activated T24-H-ras gene and five clones were isolated on the basis of increasingly transformed colony morphology and H-ras expression. A highly significant correlation between H-ras RNA levels and NK lytic sensitivity was observed. However, NIH-3T3 transfected with activated EJ-c-H-ras or transforming amounts of the c-H-ras proto-oncogene were not more NK sensitive than the parental line. Furthermore, induction of H-ras transcription in NIH-3T3 cells transfected with v-H-ras under the control of a glucocorticoid-sensitive MMTV LTR had little effect on lytic sensitivity. These results indicate that the ras-induced increase in NK sensitivity was dependent on the induction of specific cellular characteristics in the recipient fibroblast lines and was not directly related to the transformation event.