FIGURE 1.

Endoglycosidase H sensitivity of I-A^k class ii molecules. B10.Br splenocytes were lysed, and either total or Ia.2⁺ I-A^k class II molecules were immunoprecipitated with the 10-2.16 or 11-5.2 mAb, respectively. Samples were either left untreated (−) or treated with increasing amounts of Endo H. The samples were analyzed by SDS-PAGE and anti-class II antibody Western blotting. The positions of the class II α and β chains are indicated. The position of the Endo H digested α chain is indicated by an arrowhead. Surprisingly, the β chain of the Ia.2⁺ class II conformer does not exhibit Endo H sensitivity, although the β chain of total class II does. Although we do not know the precise reason for this observation, one possibility could be that differences in the conformation or mechanism of formation of the Ia.2⁺ class II molecule block β chain N-linked glycosylation. Shown are representative results from 1 of 4 independent experiments.