A nonionic block co-polymer adjuvant (CRL1005) enhances the immunogenicityand protective efficacy of inactivated influenza vaccine in young and agedmice

The use of adjuvants is one approach to improve influenza vaccine immunogen icity and efficacy, particularly in aged populations. The response of BALB/ c mice to subcutaneously administered formalin-inactivated whole influenza virus vaccine in the presence or absence of a nonionic block copolymer adju vant CRL1005 was evaluated. In young adult naive mice, the copolymer adjuva nt significantly enhanced virus-specific IgG and hemagglutination-inhibitio n (HI) antibody responses and augmented the production of IL-2 following va ccination. Influenza vaccine formulated with 2.5 mg CRL1005 significantly e nhanced the protective efficacy of the inactivated vaccine in the upper and lower respiratory tract. In mice previously infected with influenza virus or naive aged mice, inactivated vaccine administered with the copolymer adj uvant substantially enhanced the serum HI antibody response to inactivated influenza vaccine and significantly reduced lung virus titers following sub sequent challenge with live virus compared with mice administered vaccine a lone. These results suggest that the copolymer adjuvant warrants further in vestigation as a potential adjuvant for use in human vaccination against in fluenza. Published by Elsevier Science Ltd.