Figure 1.

Conformational variants of the MHC class II imposed by different peptides are detected on the cell surface by mAb. (A) Stable bulk populations of indicated L cell transfectants were stained with anti-class II mAb followed by anti-Ig-fluorescein isothiocyanate-conjugated antibodies and analyzed by FACS. A^b-pEα and A^b-mCLIP are cotransfectants of A^bα and A^bβ covalently linked to pEα^52–68 or mouse CLIP^83–103, respectively. A^b-pEα-Ii is A^b-pEα line supertransfected with Ii cDNA. In the A^b-Eα-L line the length of the poly-Gly linker matches the linker in A^b-mCLIP. (B) FACS analysis of splenocytes from wild type B6 and indicated mutant mice. Cells were stained with anti-class II mAb, followed by secondary fluorescein isothiocyanate-conjugated anti-mouse Ig (Fc-specific) antibodies and rat anti-B220-phycoerythrin conjugate. MHC class II profiles are shown for electronically gated B220-positive B cells.