Figure 2.

Expression of retrovirally transduced MHC class II_GFP fusion proteins. (A) MMP-IAβ-d-GFP and MMP-IAβ-k-GFP retroviruses restore surface expression of MHC class II in I-Aβ chain_deficient M12.C3 cells. M12.C3 cells were cultured with media alone (mock) or infected with cell-free MMP-IAβ-k-GFP or MMP-IAβ-d-GFP retroviral supernatants for 3 days. Cells were harvested, and surface expression of MHC class II was analyzed by staining with anti-MHC mAb’s followed by flow cytometry. Shown is 1 representative example of 3 independent experiments. (B) I-Aβ chains encoded by MMP-IAβ-k-GFP are expressed on the surface of cells that express endogenous MHC class II. A20 cells (H-2d) were cultured with either media alone (mock) or cell-free MMP-IAβ-k-GFP viral supernatant for 3 days. Cells were harvested, and surface expression of MHC class II was analyzed by surface staining with anti_I-Aβ^k (10-3.6) and anti_I-Aβ^d (39–10–8) antibodies followed by flow cytometry. Shown is 1 representative example of 3 independent experiments.