FIG 5.

1V270 and 1Z105 work additively to induce antigen-specific IgG and protect mice from morbidity after viral challenge. (A) WT BALB/c mice (4 to 5 animals/group) were immunized with rPR/8 HA with or without adjuvant at the indicated doses or with antigen only in the vehicle control group. Animals were bled 3 weeks after immunization and subsequently challenged with PR/8 virus. Antigen-specific antibody endpoint titers were determined by ELISA with the PR/8 virus substrate, and the endpoint IgG titer for all groups demonstrated a dose response to both single agents 1V270 and 1Z105. The log endpoint titer is a linear function of the log dose of 1V270 (P < 0.05), and 1Z105 has an additive effect on 1V270 (P < 0.0001). However, 1Z105 does not change the 1V270 dose-response relationship, apart from this additive effect (for the overall interaction, P = 0.11), except for the very highest doses (see the text). (B) Body weight data for each group receiving the indicated doses of adjuvant or control were plotted as a function of the endpoint titer. The percent initial body weight change on day 6 following a lethal viral challenge correlated with the endpoint titers (Pearson correlation coefficient r = 0.91, P < 0.0001).