Figure 1. DM loss in NOD mice results in decreased I-A^g7 surface expression.

(A) Saponin-permeabilized splenocytes from wildtype (1) or DM mutant (2) NOD mice were incubated with anti-DM or anti-Ii chain mAb and FITC-conjugated anti-rat IgG (H+L) and analyzed by FACS. The DMα mutation eliminates DM and has no effect on Ii chain expression. (B) Splenocytes from (1) wildtype, (2) DM-deficient, or (3) Ii chain mutant NOD mice were stained with biotin-conjugated mAbs as indicated, followed by FITC-conjugated avidin. The shifts were detectable with conformationally dependent mAbs directed against distinct epitopes contributed by both chains and thus reflect decreased expression rather than a serological change. Representative data from one of three identical experiments with similar outcomes are shown.