Immunostimulatory human urinary protein.

We have previously extracted a protein from inflammatory mouse granuloma that fully protects normal mice against lethal Listeria monocytogenes infection. We now report that polyclonal antibodies directed against this protein react with a human urinary fraction that also provides full protection of normal mice against L. monocytogenes. Murine monoclonal antibodies completely inhibit the protective activity of the human urinary fraction. We have purified to apparent homogeneity a human glycoprotein of 43 kDa (HGP.43), pI = 3.2 +/- 0.2. HGP.43 injected i.v. at 250 micrograms/kg fully protected mice against a lethal inoculum of L. monocytogenes. Such resistance followed injection of HGP.43, 4 days before and, still significantly, 8 hr after Listeria infection. In scid mice lacking T and B cells, similar resistance to L. monocytogenes was observed. Inflammatory murine macrophages became cytostatic against Lewis carcinoma cells after incubation with 1.5 nM HGP-43.