Potentiation of the immune response by immunization with antigens in defined multimeric physical forms.

Conventional vaccines consisting of whole microorganisms have in many cases proven ineffective. This has led to the development of subunit vaccines which contain defined protective antigens. However, subunit vaccines are frequently poorly immunogenic, requiring the addition of adjuvants and/or their formation into forms such as micelles or virosomes. Ideally a vaccine should be limited to the desired antigens, incorporated in a multimeric physically defined form into which the adjuvant is built. This is possible through use of the ISCOM (immuno-stimulating complex), a matrix of the glycoside Quil A, onto which antigens are attached by hydrophobic interaction. Experiments involving ISCOMs prepared using membrane proteins from several viruses are described. The ISCOM system can be used to enhance immune response to antigens prepared from microorganisms and cells as well as peptides and other small molecules.