IN-VITRO ACTIVATION OF ANTIGEN-PRESENTING CELLS (APC) BY DEFINED COMPOSITION OF QUILLAJA-SAPONARIA MOLINA TRITERPENOIDS

The capacity of adjuvants to stimulate cytokine production by APC is i mportant for the initiation of the immune response. Novel adjuvant for mulations based on the iscom technology have been developed using sele cted triterpenoid components from Quillaja saponaria Molina. Five of t hese new Quillaja formulations were used to prepare matrix (an antigen -free particle) and tested for their capacity to stimulate IL-1 secret ion by murine peritoneal cells in vitro. The formulation denominated Q H 7.0.3 was superior to the other matrix formulations, including the o riginal spikoside matrix. The QH 7.0.3 formulation in iscoms containin g influenza virus envelope antigens induced IL-1 secretion more effici ently than the antigen-free matrix, or a mixture of matrix and viral a ntigens, err the free Quillaja components of similar composition. Comp ared with adjuvants known as IL-1 inducers, QH 7.0.3 flu-iscoms were a s efficient as the most prominent IL-1 inducer, i.e. lipopolysaccaride (LPS) and superior to cholera toxin (CT) and muramyl dipeptide (MDP). These results indicate that the composition per se of triterpenoids i ncluded in iscoms or matrix has a prominent influence on the level of APC activation which may result in qualitatively different immune resp onses in vivo.