Figure 2.

Nfkb1^SSAA/SSAA mutation blocks the B cell antibody response to a TD antigen. WT or Nfkb1^SSAA/SSAA BM cells were mixed with μMT^−/− BM cells in a 1:4 ratio, and transferred into sublethally irradiated Rag1^−/− mice. After 8 wk, chimeras were immunized with NP₂₇-CGG alum or PBS alum controls. (A) Serum antibody response to NP₂₇-CGG immunization of WT or Nfkb1^SSAA/SSAA mixed BM chimeras assessed 7 and 14 d after challenge. Data show mean NP-specific serum IgM and IgG1 levels (±SEM) measured by ELISA. (B) Flow cytometric analysis of total naive B cells (IgM⁺B220⁺; left) and αNP-IgG1⁺ plasmablasts (PB; B220^loIgM^loIgD⁻CD138⁺; right) in the spleens of chimeras 7 d after NP₂₇-CGG immunization (mean absolute number ± SEM). (C) Flow cytometric analysis of total GC B cells (IgM^loB220⁺IgD⁻PNA^hiGL7⁺; left) and αNP-IgG1⁺ GC B cells (right) in chimeras 14 d after NP₂₇-CGG immunization (mean absolute number ± SEM). (D) Confocal microscopy of spleen sections from WT or Nfkb1^SSAA/SSAA chimeras immunized with NP₂₇-CGG (14d). GC formation was measured by staining with anti-IgD (red), anti-B220 (blue) and GL7 (green). In A–D, results are representative of at least three independent experiments with n = 5 mice per genotype. (E) WT or Nfkb1^SSAA/SSAA CD45.2⁺ BM cells were mixed with WT CD45.1⁺ and μMT^−/− BM cells in a 1:1:3 ratio, and transferred into sublethally irradiated Rag1^−/− mice. After an 8-wk reconstitution, chimeras were immunized with NP₂₇-CGG alum or alum alone. Graph shows the flow cytometric analysis of αNP⁺ IgG1⁺ plasmablasts (PB), 7 and 14 d after NP₂₇-CGG immunization. Results are representative of at least two independent experiments with n = 5–6 mice per genotype. **, P < 0.01; ***, P < 0.001.