Total IgG titres calculated in comparison to a pooled standard serum, were determined for sera from individual rabbits against bulk OMVs and the PorA P1.7,16 and FetA F3-3 antigens. The standard serum was given an arbitrary value of 10 units. Rabbits were immunized with four doses of either adjuvant alone (Control), 25 μg total protein per doses, or 50 μg total protein per doses. Blood samples were collected from all animals (n = 12) pretrial (Sample 1), and before dosing on days 22 (Sample 2, post one dose) and 64 (Sample 3, post three doses). A fourth blood sample was taken from six rabbits on day 92 (Sample 4, post four doses). The graph shows geometric mean units. Error bars indicate the 95% confidence intervals of the mean. Actual figures for the data presented are given in S2 Table.