Abstract: This invention provides methods and compositions for localized delivery of IL-12 to a desired site. The composition comprises liposomes carrying IL-12. The liposomes comprise phosphatidyl choline, phosphatidyl glycerol and cholesterol. The size and composition of the liposomes is such that there is minimal leakage into the systemic circulation. These compositions can be used for delivery of IL-12 to selected sites such as tumors.

Abstract: Methods and composition are described for low immunogenic protein, polypeptide or peptide formulations. The method comprises forming complexes of the protein, polypeptide or peptide with a binding agent which can be a serine containing compound or other phosphatidyl compounds or phospholipids. The complexes formed include simple complexes, micelles, cochleate structures, liposomes, non-bilayer and novel lipidic structures. The antigenicity and imminogenicity of the protein, polypeptides or peptides is reduced upon formation of such complexes.

Abstract: Composition and methods are described for low immunogenic protein formulations. An example of such a protein is antihemophilic factor (FVIII). The composition generally includes the protein, polypeptide or peptide, one or more agents that bind to epitope domains of the proteins to form a complex. Buffers containing salts may be used to stabilize this interaction. For example, Factor VIII and serine containing phospholipids in buffer salts containing Ca2+ and Na+ can be used to prepare protein-lipid structures. These complexes are useful for treatment of diseases such as Hemophilia. A method for the formation of novel non-liposomal structures is also disclosed.