The ISCOM: an immunostimulating complex.

Vaccine development is based largely upon the use of killed or live attenuated organisms. But most of the components of an organism are irrelevant to the generation of an immune response and some may be positively harmful. Vaccines based on protective antigens have also had a chequered history, largely because of poor antigen immunogenicity and the obligatory use of damaging quantities of adjuvant. Here Bror Morein and colleagues report on an alernative vaccine vehicle -the immunostimulating complex (ISCOM). Composed of the adjuvant Quil A and immunizing peptides, ISCOM particles contain low concentrations of adjuvant and can significantly enhance immunogenicity. If early successes are confirmed, ISCOMs may be significant part of the future vaccine programmes.