T cells infiltrate into the brain in different animal models of PD, including 6-hydroxydopamine (6-OHDA)-induced neurodegeneration in mice and rats (Theodore and Maragos, 2015; Ambrosi et al., 2017), the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model in mouse (Reynolds et al., 2010; González et al., 2013), human α-synuclein (α-syn)-overexpressing transgenic mice (hαSyn, Thy1-SNCA) (Sommer et al., 2016; Iba et al., 2020). The gene discussed is SNCA; the disease is Parkinson disease.