Figure 5.

TP^−/− CD4⁺ T cells preferentially support low-avidity IgG responses. WT or TP^−/− OT-II CD4⁺ T cells (A and B) or OVA-tet⁺ WT or TP^−/− CD4⁺ T cells (C) were adoptively transferred into SMARTA recipients before immunization with NP₁₆-OVA/CFA. On day 8 after infection, serum was isolated and IgG titers against NP₈-BSA and NP₄₁-BSA were measured in limited dilution assays. (A) Each line presents a dilution series of serum isolated from an individual mouse. (B) IgG titers to NP₈- and NP₄₁-BSA after transfer of WT or TP^−/− OT-II CD4⁺ T cells. (C) IgG titers to NP₈- and NP₄₁-BSA after transfer of OVA-tet⁺ WT or TP^−/− CD4⁺ T cells. Data in B and C are pooled from two independent experiments with 4–5 mice/group and analyzed by ANOVA with Sidak’s multiple comparison test. **, P < 0.01; ***, P < 0.001.