FUNCTIONAL-ASPECTS OF ISCOMS

The iscom is a delivery system, designed for both parenteral and mucos al modes of administration, for both antigens and adjuvants, component s which are interchangeable. By the parenteral route a prominent syste mic Th1 type of response is evoked, but the mucosal immunoglobulin A ( IgA) response was insignificant. Intranasal (i.n.) immunization with i scoms evoked potent mucosal IgA response and serum IgG which was much higher than that induced by i.n. administration of the B subunit of ch olera toxin (rCTB), both to rCTB itself as well as to co-administered antigen. The immunomodulatory effect on rCTB or co-administered antige ns imposed by the iscom was demonstrated by a potent mucosal IgA switc h and an enhanced IgG2a serum response. The incorporation of a targeti ng molecule in the iscom enhanced the remote IgA response in the genit al tract mucosa. The capacity to induce CD8-restricted cytotoxic T lym phocytes (CTL) is unique for the iscom as a nonreplicating system, whi ch is facilitated by the delivery of antigens to the cytosol. The immu nomodulatory capacity of iscoms also paved the way to override the inh ibitory effect of maternally derived antibodies and the relative unres ponsiveness of an immature neonatal immune system.