Figure 2

Analyses of DLL expression by Immunoblot and FACS using cell-lines over-expressing DLL. (A) Protein blots were prepared from TSt-4 thymic stromal cell-lines over-expressing human DLL1 or 4, and incubated with polyclonal antibodies specific for DLL. Both H20 and H265 only stained lanes containing TSt-4-DLL1 extracts, with a main band at 78 kDa. H265 stained additional bands at 50 kDa and 230 kDa, which could represent processed and glycosylated DLL-1, respectively. In contrast to H20, H265 also heavily stained the marker-lane, indicating that the specificity of this polyclonal antibody preparation is not limited to DLL. (B) Indicated cells were harvested using trypsin-EDTA, and incubated with H265 and H20 + control polyclonal antibodies specific for IRF1 and ACE. Control antibodies were selected based on species-origin and specificity for non-surface antigens. Both H265 and H20 showed weak, yet specific staining of TSt4-DLL1.