It relates to BALB/c mice that defect programmed cell death-1 receptor (PD-1), a screening method of autoimmune disease medicine by use of these mice, IgG self-reactivity antibody that the mice produce specifically, protein specifically reacted to the antibody and produced in heart, and an diagnostic method in dilated cardiomyopathy by use of the protein.Because PD-1 deficient BALB/c mice spontaneously develop autoimmune disease, specifically dilated cardiomyopathy, they are useful to screening for medicines against these diseases.
