Fig. 5. Neutralization of high ICOSL levels in ADAM10^B−/− restores germinal center B cells and antibody production.

(A) model depicting antibody administration schedule and immunization strategy. (B–C) ADAM10^B−/− mice were administered 30μg MIL-5733 every other day and ICOSL levels (B) on B cells and ICOS surface levels (C) on CD4⁺ T cells were measured by flow cytometry at indicated time points from the peripheral blood. (D–J) WT and ADAM10^B−/− mice were administered MIL-5733 every other day and immunized with 10μg NP₃₁-KLH i.p. and in each hind footpad. Draining lymph nodes were analyzed for germinal center B cells (D – E) by flow cytometry as determined by CD95⁺ GL7^hi B cells and T_FH (F, G). (H) ICOS levels on T_FH from WT (black line), ADAM10^B−/− (red line), and ADAM10^B−/− + MIL-5733 (purple line) were determined by flow cytometry. Isotype control staining shaded gray. (I) quantification of H. (J) total and high affinity IgG₁ were determined by ELISA as in Materials and Methods. n.s., not significant (P ≥ 0.05). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Kruskal-Wallis non-parametric test (A, E, G, I, J). Data are pooled from two (A – J mean ± s.d.) independent experiments.