In the light of recent reports describing conflicting results as to their effect on AD-related pathology (Baruch et al., 2016, Latta-Mahieu et al., 2017), we aimed to observe PD-1-mediated immunoregulatory effects in another model of neurodegenerative disease, the prion ME7 mouse model. The gene discussed is PDCD1; the disease is Alzheimer disease.