Immunogenicity and kinetics of anti-OPS IgG induced by monovalent KPO1 conjugates with PA rFlaA or rFlaB in mice.

(A) Anti-OPS IgG was assessed in sera obtained 28 days after the last dose from mice (n = 59–60) immunized with three doses of PBS (triangles), O1:rFlaA (circles) or O1:rFlaB (squares). Statistical significance by Mann-Whitney is indicated. * P ≤ 0.0001. Each point indicates the serum titer from an individual mouse. Bars indicate the geometric mean titer. (B) Anti-OPS IgG titers in select high (black, n = 4–5), moderate (blue, n = 5) or low (red, n = 5) responders in sera taken directly prior to immunization or 14 days after the 1st, 2nd, or 3rd dose of O1:rFlaA (circles) or O1:rFlaB (squares). Bars indicate the geometric mean titer.