An antibody for being specifically bound to a pro brain-derived neurotrophic factor (pro-BDNF) and a bound epitope. The antibody and the protein are used for treating autoimmune diseases. By inhibiting the activity induced by the pro-BDNF, rheumatoid arthritis, psoriasis, systemic lupus erythematosus, lupus nephriti, chronic obstructive pulmonary diseases, asthma or cystic fibrosis, multiple sclerosis and other autoimmune diseases are treated.
