A randomized, double blind study in young healthy adults comparing cell mediated and humoral immune responses induced by influenza ISCOM (TM) vaccines and conventional vaccines

Although current influenza vaccines have been shown to reduce influenza-rel ated morbidity and mortality, there is a desire to develop more efficacious products. Vaccines which can induce CD8(+) cytotoxic T cell (CTL) response s in addition to strong antibody responses may be more effective in prevent ing disease since it has been demonstrated that CTL contribute to protectiv e immunity, even against drift variants of influenza A viruses. The immunog enicity of two types of experimental influenza vaccines, which were based o n immune stimulating complexes (ISCOM(TM)), were evaluated and compared wit h a conventional non-adjuvanted inactivated split virion vaccine, after imm unization of human volunteers. In this randomized, double blind study, it w as shown that the ISCOM(TM) vaccines altered the kinetics of the serum anti body response, resulting in more rapid titer rises against the vaccine stra ins. This accelerated antibody response coincided with enhanced in vitro pr oliferative T cell responses, which were observed shortly after vaccination . In addition, CTL responses were observed in a higher proportion of the va ccinees receiving an ISCOM(TM) vaccine, than in vaccinees receiving the con ventional influenza vaccine. (C) 2000 Elsevier Science Ltd. All rights rese rved.