FIG 4.

Individual subjects with increases in serum anti-FH reactivity after vaccination. (A to D) Four subjects had increases in serum anti-FH antibody titers 3 weeks to 2 months after vaccination (preimmune [Pre-]; light blue circles with solid lines), 3 weeks to 2 months postimmunization (orange squares with dashed lines), and 4 to 5 months postimmunization (black “X” symbols with dotted lines). Subjects AA, BB, and CC were immunized with MenB-4C (panels A, B, and C, respectively). Their titers returned to baseline (panel A and C) or to a level close to baseline (panel B) by 4 to 5 months. Subject DD (panel D) was immunized with an OMV vaccine without recombinant FHbp as part of historical control vaccine studies (Table 1). This subject did not have a subsequent postimmunization serum sample available to determine if the increased anti-FH antibody persisted. (E) Serum FH function as measured by alternative-pathway-mediated hemolysis. Data represent unvaccinated adult sera (n = 7), each with low anti-FH binding by ELISA (OD₄₀₅ of <0.47 at a 1:50 dilution), and postvaccination sera (3 weeks to 2 months; subjects AA, BB, CC, and DD). Controls with abnormal FH function included a serum sample from a patient with aHUS and a human serum pool mixed with goat antiserum to human FH as described in the Fig. 3B legend. SE, standard error.