B Cal/7/9-specific serum antibody titers in individual sera at indicated time points. Black lines: individual animals, red lines: mean titer. Statistical significance between pre-immune and immune sera was determined using Friedman test with Dunn's multiple comparison testing (*p<0.05, **p<0.01). The lower table indicates Cal/7/9-specific MN50 and HAI mean titers. Assays were performed in technical duplicates. 