The present invention provides, among other things, a polypeptide, and a pharmaceutically acceptable salt thereof, that inhibits the binding of IL-6 ligand with IL-6 receptor under physiological conditions, a nucleic acid that encodes such a polypeptide and can be expressed in a cell, a nucleic acid that comprises or encodes an antisense nucleic acid molecule or a ribozyme that is specific for such a polypeptide, an antibody that is specific to such a polypeptide, an anti-antibody thereto, a composition comprising such a polypeptide, nucleic acid, antibody or an anti-body and a carrier therefor, a composition comprising a solid support matrix to which is attached an above-described polypeptide or an anti-antibody to a specified polypeptide sequence, a method of prophylactically or therapeutically inhibiting IL-6 signaling in a mammal in need thereof, a mammal in need thereof, and a method of removing IL-6 ligand from a bodily fluid of an animal.