As isolated antibody binding to human EPO receptor. The antibody specifically binds EPO receptor fragment GLSDGPYSNPYENSLIP (SEQ ID NO:26), comprises a phosphotyrosyl residue at position 461, and specifically binds to activated human EPO receptor and discriminates between non activated and activated EPO-R. The heavy chain variable domain comprises a CDR3 region of SEQ ID NO:9, a CDR2 region if SEQ ID NO:10 and a CDR1 region of SEQ ID NO:11, and the light chain variable domain comprises a CDR3 region of SEQ ID NO:12, a CDR2 region of SEQ ID NO:13, and a CDR1 region of SEQ ID NO:14.
ANTIBODIES AGAINST PHOSPHORYLATED TYROSINES ON ERYTHROPOIETIN RECEPTOR (EPOR)