[General and primary thermoresistance in genetically differing variants of murine neuroblastoma].

General and primary thermoresistance of mouse neuroblastoma clonal cell lines derived from N18A subline was studied: the N18A1 clonal cell line was not treated by heat, the NTR1 was obtained by one-step selection for resistance to the long action of the temperature 40 degrees C, the NHSR1 was obtained by multistep selection for resistance to short-time treatment at 44 degrees C. The NHSR1 clonal line was shown to have higher general and primary thermoresistance by comparison with that of N18A1 cells. The NTR1 cell line, capable of unlimited proliferation at 40 degrees C, did not differ in general resistance but displayed a slower primary resistance compared to that in the N18A1 cells. Cells of all the three clones were found to be capable of temporary increasing in primary thermoresistance, i.e. hardening. A possible contribution of the primary resistance into the general one in cells of all the selected clones has been discussed.