Fig 3.

Humoral response following immunization with AuNP vaccines. (A) Antigen-specific serum IgG antibody titers were determined via ELISA with plates coated with individual antigens. (B and C) Pathogen-specific serum IgG (B) and fecal IgA (C) titers were determined by coating plates with lysates of individual pathogens. Endpoint titers are defined as the average +2SD of the levels measured for naïve sera. Each dot represents individual mice, and the averages (±SEM) are shown for all antibody data. (D) Micrographs showing cross-reactivity of antibodies in immune sera with both C. rodentium and EHEC; bacteria were incubated in the presence of heat-inactivated sera from AuNP-EscC-, AuNP-LomW-, or AuNP-Eae-immunized mice or from adjuvant-only-treated mice. Bacteria were stained with a goat anti-mouse IgG conjugated to Alexa-488 secondary antibody (green), and DNA was probed with DAPI (blue). Green indicates bound antibody to surface of bacterial cells. Significant differences in antigen-specific titers were determined by the Mann-Whitney non-parametric test, and significant differences in pathogen-specific titers were determined via the Kruskal-Wallis’s test followed by Dunn’s multiple comparisons test. *P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001, and ****P ≤ 0.0001.