Th-1 and Th-2 cytokine and IgG subclass responses in mice immunized with pandemic H7N9.

DBA/2J mice were immunized with whole-virus (WV) H7N9 vaccine or buffer as control on days 0 and 21. Spleen cells were collected 7 days after the first, or 21 days after the booster immunization (i.e. 42 days after the first), and stimulated with whole-virus (WV) H7N9 vaccine or recombinant H7 HA (rHA) for the determination of cells responding to the antigens by secretion of either IFN-γ (A) or IL-4 (B) using an ELISPOT assay. Statistically significant differences of comparisons between T cell responses in mice receiving H7N9 vaccine or buffer are shown. H7 HA-specific IgG subclass responses were analyzed by ELISA using sera collected on day 42 (C). IgG subclass responses on day 42 were compared by ANOVA. ***, p<0.0001; ns, not significant.