Fig 2. Anti-COPS IgG responses in adult and infant mice after immunization with S. Enteritidis COPS:FliC alone or formulated with different adjuvants.
(A) Infant and adult mice (n = 16–20/group) were immunized as described in Fig 1. Serum anti-COPS IgG titers taken 12–14 days after each dose were determined by ELISA. Each point represents an individual mouse. Red squares indicate mice that succumbed to subsequent challenge. Bars represent the GMT for adults (grey) and infants (white), and were compared using a two-tailed Mann-Whitney U test. Adjustments for multiple comparisons were not made. ns, not significant. *P ≤ 0.05; **P ≤ 0.005; ***P ≤ 0.0005 for indicated comparisons. (B) Reverse cumulative distribution curves for post 3rd immunization anti-COPS IgG titers for adults (grey circles) and infants (white circles) are depicted. Dotted lines indicate the cut-off for seroconversion (50 EU/mL), which represents a 4-fold rise over the anti-COPS IgG GMT for PBS controls.