CD8A and Parkinson disease: In specificity, intestinal infection caused by lipopolysaccharides from gram-negative bacteria could trigger mitochondrial antigen presentation (MitAP) in autoimmune CD8 + T cells, which could enter the brain to attack dopamine neurons and cause a sharp decrement in the density of dopaminergic axon expansion in the striatum, leading to movement disorders like Parkinson’s disease (PD) in mice (Matheoud et al., 2019).