Intranasal immunization with influenza virus and Korean mistletoe lectin C (KML-C) induces heterosubtypic immunity in mice

Abstract

The mucosal adjuvanticity of Korean mistletoe lectin C (KML-Q was investigated in mice intranasally immunized with inactivated influenza virus (H IN1). Mucosal and systemic immune responses were compared to those induced with cholera toxin B subunit (CTB). KML-C increased influenza-specific antibodies with dominant IgG1 subclass in serum, IgG in genital secretions and IgA in saliva, and significantly enhanced in fl uenza- specific lymphocyte proliferation and cytotoxic activity in spleens and in mediastinal lymph nodes. When KML-C was used as a mucosal adjuvant, mice were completely protected from mortality after the challenge with a homologous (HINI) mouse-adapted influenza virus. After challenge with heterologous (H3N2) influenza virus the level of heterosubtypic immunity in KML-C-treated mice was comparable to that of mice that received CTB as adjuvant. These findings suggest that KML-C may be used as an effective mucosal adjuvant. (c) 2007 Elsevier Ltd. All rights reserved.