Preparation of Immune Stimulating Complexes (ISCOMs) as Adjuvants

Abstract

Purified proteins are often poorly immunogenic and in such cases the induction of primary immune responses requires use of an adjuvant. The immune stimulating complex (ISCOM) has a unique ability to provoke a full range of immune response to protein antigens, after both parenteral and oral immunization. This unit describes techniques for incorporating proteins into the ISCOM structure, a process that requires the presence of exposed hydrophobic regions on the protein. The basic protocol outlines a method for preparation of ISCOMs containing inherently nonhydrophobic proteins, to which palmitic acid has been attached covalently. Two alternate protocols are given that do not require covalent modification of the protein. In the first, hydrophobic groups are revealed by acid treatment of the protein. The second describes preparation of ISCOMs containing integral membrane proteins that therefore possess a hydrophobic transmembrane domain.

Immune stimulating complexes as mucosal vaccines

“…However, it remained difficult to incorporate purified hydrophilic protein antigens, thus limiting the potential usefulness of the approach. This was overcome by the chemical modification of proteins by acidification to reveal hydrophobic groups 13 or by addition of hydrophobic regions by chemical linkage of palmitic acid tails 14 . Using the latter approach, we and others have incorporated a variety of proteins into ISCOMs including ovalbumin, 15 cytochrome c, 15 gp120 from HIV 16 and somatostatin–avidin complexes 17 …”