HeLa Tet-on cells expressing H-2K<sup>b</sup> were nucleofected with 4×100 nM siRNA.

<p>Twenty-four hours later, the cells were electroporated with inducible plasmids encoding amyloid beta preceded by a signal peptide (+SP) or not (−SP), or encoding proinsulin, all tagged with the S8L peptide at the C-terminus. Protein expression was induced immediately by addition of 1 µg/ml doxycylin. Forty-eight hours later, K<sup>b</sup>/S8L complexes on the cell surface were detected using mAb 25D1.16 (Ab1) followed by FITC-labeled goat anti-mouse Abs (Ab2) and Alexa488-labeled goat anti-FITC Ab (Ab3). Control samples were HeLa-K<sup>b</sup> cells pulsed for 2 h with 10<sup>−8 </sup>M S8L and stained with Abs 1, 2 and 3 or with Abs 2 and 3 only, as well as peptide-pulsed HeLa cells expressing H-2K<sup>d</sup> stained with Abs 1, 2 and 3. One of two experiments is shown.</p>