Figure 3.

Endostatin binds to purified α₅β₁ integrin in a concentration-dependent and specific manner in a solid-phase ligand binding assay. (A) α₅β₁ integrin was added to wells coated with endostatin as indicated, and incubated overnight at +4°C. Anti-α₅ serum, biotinylated anti-rabbit IgG antibodies, and ABC complexes were used to detect bound integrin. (B) Soluble inhibitory anti-integrin antibodies were added to block the interaction between endostatin and α₅β₁ integrin, and incubated overnight at +4°C. Bound integrin was detected as above. Anti-integrin antibodies used were: anti-α₅ (NKI-SAM-1) and anti-β₁ (P4C10). Results are expressed as the mean +/− SD.