Expression profiles of A2, CD80, and CD83 molecules on K562-derived stable cell lines coexpressing A2 with either CD80, CD83, or both CD80 and CD83. K562-derived stable transfectants were analyzed by flow cytometry with specific antibody (open curve) and an isotype control (filled curve) coupled to the appropriate chromophore. Note that there is a dim expression of endogenous CD80 on K562 cells.