Figure 5. DP^84GGPM87 binds to Ii via a non-CLIP region(s) in neutral pH conditions.

(a,b) HEK293 cells were transfected with the indicated combinations of genes. Total cell lysates were immunoprecipitated with anti-DPβ mAb and immunoblotted with anti-Ii or DPβ mAb. (c–e) Lysates of T2/DP transfectants (c,d) or HEK293 cells transfected with the indicated combinations of DP and Ii^R-CLIP genes (e) were immunoprecipitated with anti-DPβ mAb. Note that T2 cells naturally express Ii. The immunoprecipitates were washed with buffer of graded pH as indicated and immunoblotted with anti-Ii or DPβ mAb. (f,g) T2 and T2/DP4 were cultured in the presence or absence of 10 μg ml⁻¹ BFA (f) or 40 mM NH₄Cl (g). Cells were further treated with DSP at the indicated concentrations for 2 h. Non-reduced samples were immunoblotted with anti-Ii (left) or DPβ (right) mAb.