Fig. 10.
Activation of HEL-specific B cells by misfolded HEL protein presented on MHC class II molecules. (A) Plasmids containing wild-type HEL (wtHEL) and cysteine-mutant HEL (mutHEL) were co-transfected into CHO cells with GFP plasmid in the presence or absence of I-Ak. Plasmids containing membrane-tethered wild-type HEL (membrane HEL) were also co-transfected with GFP plasmids into CHO cells. GFP-positive cells were sorted 2 days later and co-cultured with the Gloop4-BCR-transfected A20 B cell line, G4-A20. G4-A20 was also stimulated with soluble or immobilized (plate-bound) HEL protein. Cells stimulated for 4h were stained with anti-CD69 and B220 (anti-CD45) mAbs. (B) G4-A20 was stimulated as in (A) and proportions of cells expressing CD69 within B220-positive cells are shown. Data are means ± SD of triplicate cultures, representative of three independent experiments.