A microbial peptide shared by several major classes of bacteria including Escherichia coli, which is one of the most common commensal bacteria of the human gut microbiota, can induce multiple sclerosis (MS)-like disease in humanized mice by cross-reacting with a T cell receptor that recognizes a peptide from myelin basic protein acting as candidate MS autoantigen [106]. The gene discussed is MBP; the disease is myeloid sarcoma.