INFLUENZA-VIRUS NEUTRALIZING ANTIBODIES AND IGG ISOTYPE PROFILES AFTER IMMUNIZATION OF MICE WITH INFLUENZA-A SUBUNIT VACCINE USING VARIOUS ADJUVANTS

The influence of various adjuvants on the development of influenza vir us neutralizing antibodies and distribution of anti-influenza virus Ig G isotypes after immunization of mice with influenza A (H3N2) subunit vaccine was investigated. Serum titres of influenza virus neutralizing antibodies and titres of influenza specific IgG isotypes were determi ned by a neutralization enzyme immunoassay (N-EIA) and a cell-associat ed antigen enzyme immunoassay (CA-EIA), respectively. Ser um antibody titres as measured by the two tests correlated highly (r=0.82; P<0.001 ). N-EIA titres were enhanced by 38- and 34-fold, when L180.5/RaLPS an d FCA, respectively, were administered with I mu g of vaccine. The adj uvants e-VAC, L180.5 [W/O/W], L180.5 alone and Montanide ISA 740 were only moderately or not effective in enhancing the immune response to t he 1 mu g dose of vaccine. The Q-VAC and L180. 5/RaLPS adjuvants favou red IgG2a and IgG2b isotype responses to influenza compared to the oth er adjuvants. We suggest that N-EIA and CA-EIA may be valuable tools t o monitor the effects of adjuvants on the neutralizing antibody and an tibody isotype responses after influenza vaccination. (C) 1997 Elsevie r Science Ltd.