Immune cells infiltrate tumors and make up a significant component of the multicellular cancer microenvironment, yet the immune system often fails to prevent tumor formation and progression. One explanation for this paradox is the presence of tolerance-promoting regulatory T cells (Tregs). Tregs were known to be essential for maintaining self-tolerance. Tregs have been found to promote tolerance to tumors in mouse models. Treg infiltration in human tumors and malignant ascites is associated with worse clinical outcomes for various types of cancers.

The possibility to induce tolerance to brain ischemia by different stimuli draws attention of many researchers. The perspective to make the brain, even transiently, more resistant to reduced blood flow seems to be very attractive considering its potentially clinical application. Molecular mechanisms of preconditioning are known only fragmentary, so far. The present work summarizes the current know- ledge about factors involved in the induction of brain ischemic tolerance.

The possibility to induce tolerance to brain ischemia by different stimuli draws attention of many researchers. The perspective to make the brain, even transiently, more resistant to reduced blood flow seems to be very attractive considering its potentially clinical application. Molecular mechanisms of preconditioning are known only fragmentary, so far. The present work summarizes the current know- ledge about factors involved in the induction of brain ischemic tolerance.