Fig. 3.

Teff and Treg immunity in AD and PD. Pathogenic changes observed in AD brain include accumulation of intraneuronal neurofibrillary tangles (NFTs) of Tau protein and extracellular amyloid beta (Aβ) plaques. The accumulated peptides facilitate neuroinflammatory Teff entry into the brain where they affect resident microglia cells to induce local inflammatory responses. In PD, α-synuclein accumulation promotes immunoreactive Teff entry into the brain to activate microglia, compromising nigrostriatal axis between the substantia nigra pars compacta (SNpc) and striatum that execute motor commands. Immunoregulatory Tregs can restore homeostatic balance in the brain through clearance of neuroimmunogens, microglial polarization and restoration of normal neural functions