FIGURE 1.

Generation of endogenous CD40 cytoplasmic domain mutant mice. (A) Schematic representation of WT CD40 and mutants. CD40ΔT6 was generated by deletion of the sequence ²³⁴RQDPQE²³⁹. CD40ΔT2 was made by deletion of the sequence ²⁵¹PVQET²⁵⁵. CD40ΔT2* was made by truncation of a sequence distal to amino acid 245 by inserting two stop codons (TAATAG). (B) Representative FACS analysis of CD40 surface expression on the same mouse spleen DCs (PI⁻CD11c⁺B220⁻) and B cells (PI⁻CD11c⁻B220⁺) that were in 4°C overnight (gray) or incubated with CpG overnight (red). (C). CD40 was immunoprecipitated from cell lysates of the indicated mice, and we analyzed bound proteins by immunoblotting using TRAF2 Ab. The lower two panels show expression of TRAF2 and CD40 in whole-cell lysates. The arrow indicates the position of TRAF2, and *ns indicates the position of a nonspecific band present even in CD40^−/− mice.