Fission-neutron-induced Expression of a Tumour-associated Antigen in Human Cell Hybrids (HeLa × Skin Fibroblast): Evidence for Increased Expression at Low Dose Rate

Summary

The induction of a tumour-associated antigen in a human cell hybrid line (HeLa × skin fibroblast) following exposure to fission neutrons of average energy 0·85 MeV (Janus reactor, Argonne National Laboratory) at two dose rates, 0·086 and 10·3 cGy/min, has been examined. The dose-response data obtained indicate the lower dose rate to be 2·9-fold more effective than the higher in inducing expression of the tumour-associated antigen, while there was no significant dose-rate effect in terms of cell killing. These results are qualitatively in agreement with previous observations using neutrons from the Janus reactor for the neoplastic transformation of C3H10T½ cells and Syrian hamster embryo cells.