Assessment of Immunoglobulin G subclasses and the longevity of antibody responses induced by immunization.

<p>Immunoglobulin G (IgG) subclasses were determined in serum collected three weeks after the third immunization with rMUL2232 (A1) and the indicated adjuvant or rMUL3720 (B1) and the indicated adjuvant. ELISA on recombinant protein was performed with secondary antibodies specific for four IgG subclasses: IgG1 (black), IgG2a (dark grey), IgG2b (light grey), IgG3 (very light grey). Depicted are the mean individual endpoint IgG titers determined in one single ELISA (bar), and the standard deviation (error bar). Overall statistical significance was calculated by Kruskal-Wallis test (A1: P_IgG1 = 0.0265., P_IgG2a = 0.0205, P_IgG2b = ns., P_IgG3 = 0.0276; B1: P_IgG1 = 0.0034., P_IgG2a = 0.0017, P_IgG2b = 0.0048, P_IgG3 = ns.). Individual statistical differences between groups were assessed by the Dunn procedure and are depicted if detected (* <i>p</i> ≤ 0.05; ** <i>p</i> ≤ 0.01). The ratio of IgG2a to IgG1 was determined for individual animals accordingly (A2 and B2). Depicted are the individual values, the mean IgG2a to IgG1 ratio (bar) and the standard deviation (error bar). Overall statistical significance was calculated by Kruskal-Wallis test (A2: P = ns.; B2: P = 0.0024). Individual statistical differences between groups were assessed by the Dunn procedure and are depicted if detected (** <i>p</i> ≤ 0.01). Total IgG titers in individual immunized mice three weeks (t1) and six months (t2) after the third immunization were compared by Western blotting on <i>M</i>. <i>ulcerans</i> lysate. Depicted are individual Western blot endpoint titers and the median per group (line) for rMUL2232 immunized animals (A3) and rMUL3720 immunized animals (B3). Statistical significance was assessed by Mann-Whitney test and is depicted if detected (* <i>p</i> ≤ 0.05; ** <i>p</i> ≤ 0.01).