Id-CTLA4 retains the binding activity for B7-1 and B7-2.

(A) DC2.4, a murine dendritic cell line, was stained with Id, Id-GM, or Id-CTLA4. (B) CHO (panels i,iv, and vii), CHO/B7-1 (panels ii,v, and viii), and CHO/B7-2 (panels iii,vi, and ix) cells were stained with Id (i-iii), Id-GM (iv-vi), or Id-CTLA4 (vii-ix). Cells were then washed and incubated with FITC-conjugated goat antihuman κ Ab. Dashed lines represent fluorescence from cells without addition of the tested Id fusion proteins.