B-cell migration, proliferation, and antibody production. (A) Migration (after 3 hours) of splenic B220⁺ cells from WT versus KI mice to chemokines S1P and SDF-1. (B) S1P1 (EDG1) receptor expression in splenic B220⁺ cells from KI (blue) and WT (red) mice. Dotted lines represent isotype controls. (C-E) Viability/cell growth curves in splenocytes of WT and KI mice were analyzed using WST-1. Viability/proliferation of total splenocytes stimulated with (C) α-IgM, or (D) α-CD40 was more compromised than proliferation of cells stimulated through the (E) TLR by LPS. (F) NP-specific IgM and IgG titers from sera of WT and KI mice immunized with either NP-LPS or NP-CGG. (G) WT and KI mice (n = 5 each) were immunized with either NP-LPS or NP-CGG, and total IgM and IgG antibody concentrations were examined in sera of mice at day 7 or day 14, respectively. (H) Crossing the KI mice to β-actin cre mice to produce KI^neo− mice rescued antibody production in the neo-less KI mice. WT and KI^neo− (neo-less) mice (N = 5 each) were immunized with NP-CGG and NP-specific antibody titers as well as total antibody concentrations measured in mouse sera at day 21; mice were given a boost at day 14.