Figure 4.

Specific humoral responses and affinity maturation in traf5^−/− mice. Traf5^+/+ (●) and traf5^−/− (○) mice were immunized with 5 μg of NP₂₂-CG/alum on day 0 and boosted with the same dose on day 21. NP-specific IgM (A), total IgG1 (B), and high-affinity IgG1 (C) antibodies were measured at the indicated time points. IgM antibodies were determined by ELISA against densely haptenated BSA (NP₂₂-BSA). Total and high-affinity IgG₁ antibodies were determined by ELISA against NP₂₂-BSA and NP₂-BSA, respectively. The levels of anti-NP IgG1 are indicated as arbitrary units by using an NP-specific IgG1 mAb of known affinity (C6; K_d = 3.3 × 10⁻⁷ M) as a standard. The levels of anti-NP IgM are indicated as arbitrary units determined by using an immune sera as a standard. In D, high-affinity/total IgG1 ratios were calculated from the value in B and C for each individual. Bars indicate the means of four mice in each experimental group. Data represent one of two independent experiments with similar results.