Parent phenotype and age dependence, on rat glioma tumor rejection

The brain, despite the blood-brain barrier, does not escape to the highly variable host rejection response mediated by a very strong and complex immune reaction when rat glioma cells are transplanted into the adult animal.

Crosses were performed among parents that are able or enable to reject a well-known brain tumor cell line (C6). Newborn animals were also challenged with rat glioma cells both in the brain and the side flanks.

The percentage of susceptibility or resistance to develop a lethal glioma can be estimated knowing the parental phenotypes. When both parents had rejected an induced tumor, 63% of the progeny will also reject it. Similarly, if both parents died as a consequence of the tumor, 70% of the progeny would also be unable to reject the challenge of glioma C6 cells. Newborn animals do not have a mature immune system and they tolerate transplanted cells much better than adults. We found no rejection to glioma C6, at both brain and side flank sites, in 1-day-old neonatal Wistar rats. Tumors were beginning to be eliminated if the cells are inoculated at day 3 from birth on the flanks, and at 1 week from birth on the brain.

There is a genetic component conferring susceptibility or resistance to the lethal effect of tumor development and progression depending on the parental phenotype of the adult rats. Neonatal rats represent a much more reliable model than adults to study experimental therapies against gliomas.