CD4 and demyelinating disease: Using an OCA-B reporter mouse, we find that OCA-B expressing CD4+ T cells taken from mice primed with myelin oligodendrocyte glycoprotein (MOG) peptide preferentially display pathogenic stem-like gene expression patterns and preferentially transfer demyelinating disease, highlighting OCA-B as both a marker and promoter of encephalitogenic autoimmune CD4+ T cell activity.