There is accumulating evidence that CD8-positive (CD8 + ) T-cells and MHC-I expression may also play a role in neurodegeneration associated with multiple sclerosis (MS). We investigated the role of MHC-I and CD8 + T-cells by studying experimental autoimmune encephalomyelitis (EAE) in beta-2 microglobulin knockout mice induced by myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 or whole rat myelin basic protein (rMBP). For both encephalitogens and even after reconstitution of the immune system with MHC-I-positive bone marrow and transfer of mature CD8 + T-cells (iMHC-I + CD8 + β2m−/− mice), the disease course in β2m−/− mice was significantly more severe with a 10-fold increased mortality in the β2m−/− mice as compared to wild-type C57BL/6 mice. EAE in β2m−/− mice caused more severe demyelination after immunization with MOG than with rMBP and axonal damage was more marked with rMBP as well as MOG even in iMHC-I + CD8 + β2m−/− mice. Immunocytochemical analysis of spinal cord tissue revealed a significant increase in macrophage and microglia infiltration in β2m−/− and iMHC-I + CD8 + β2m−/− mice. The different pattern of T-cell infiltration was underscored by a 2.5-fold increase in CD4-positive (CD4 + ) T-cells in β2m−/− mice after induction of MOG 35-55 EAE.We conclude that lack of functional MHC-I molecules and CD8 + T-cells aggravates autoimmune tissue destruction in the CNS. Enhanced axonal damage speaks for pathways of tissue damage independent of CD8 + T-cells and neuronal MHC-I expression.