Patent 7311902 was granted and assigned to Smithkline Beecham Limited on December, 2007 by the United States Patent and Trademark Office.
Human interleukin-18 (IL-18) polypeptides and substitution mutants thereof were conjugated to water-soluble polymers at specific sites on the human IL-18 protein. These conjugated human IL-18 and substitution mutants thereof retain biological activity. These conjugated cytokines demonstrate enhanced and unexpected biological properties when compared to the corresponding unconjugated cytokines.