Purification of a 92 kDa human immunostimulating glycoprotein obtained from the Tamm-Horsfall glycoprotein

A purification method for a human urinary glycoprotein (HGP92) dissociated from Tamm Horsfall protein (THP) is described. Tamm-Horsfall protein, obtained by salt precipitations, was again precipitated in presence of monovalent ions. In these conditions, Tamm-Horsfall protein displayed a tendency to form a gel. After ultracentrifugation, HGP92, which was trapped in the gel, was dissociated from Tamm-Horsfall protein and found in the supernatant. The final step of purification of HGP92 was chromatography on a DEAE Affigel blue column. Injected intravenously, HGP92, but not THP, protected mice against a lethal inoculum of Listeria monocytogenes. This procedure has the advantage of being easy to perform, and enables preparation of large amounts of HGP92. These results suggest that the previously described 'immunostimulating' properties of Tamm-Horsfall protein were, in fact, a consequence of its contamination by HGP92.