STUDIES ON EXPERIMENTAL ADJUVANTED INFLUENZA VACCINES - COMPARISON OFIMMUNE STIMULATING COMPLEXES (ISCOMS(TM)) AND OIL-IN-WATER VACCINES

Detergent-disrupted influenza virus vaccines, formulated as Iscoms(TM) or oil-in-water (o/w) emulsions, were administered parenterally to mi ce and evaluated for immuno-genicity and protective efficacy. Both for mulations enhanced both primary and secondary serum antibody responses , The magnitude of these responses with o/w emulsions was further enha nced by the addition of the non-ionic block copolymer L121 in the emul sion. Four weeks after primary immunization, mice were challenged by e xposure to an aerosol containing infectious virus. Resistance to chall enge in terms of survival rate and weight change correlated well with serum antibody titre for all formulations, Two major differences were observed between the adjuvant formulations, Iscom(TM) vaccines, formul ated with Quil-A or the less toxic Quillaia saponin preparation Iscopr ep(TM) 703, induced specific cytotoxic T-lymphocyte responses, whereas the o/w-based vaccines did not. In addition, dose-site reactivity stu dies in sheep showed that Iscom(TM) vaccines were less reactive than o /w-based vaccines, the degree of reactivity of the latter increasing s harply with increasing L121 concentration. On the basis of these studi es, Iscoms were chosen for development as a potential adjuvant for hum an influenza vaccines. (C) 1998 Elsevier Science Ltd. All rights reser ved.