Figure 5

Effect of soluble anti-integrin antibodies on fibronectin-induced IL-8 secretion. Cells were cultured on either fibronectin or BSA substratums for 72 h prior to assays. The effects of fibronectin on both IL-8 secretion (A) and cell numbers (B) were abolished by both lone anti-β1 integrin antibodies and by anti-α5 and -αV antibodies used in combination. Use of the anti-α5 antibody alone did not affect IL-8 levels but abolished fibronectin-induced cell proliferation. Single use of the anti-αV antibody resulted in increased IL-8 levels but did not affect proliferation. When IL-8 levels were expressed as a fraction of the percentage change in cell numbers, secretion was decreased by fibronectin in these experiments (C). This decrease was not affected by control IgG or anti-α3 or -αVβ5 antibodies. Anti-β1 and α5 antibodies resulted in an increase in IL-8 secreted per cell, which was greater on fibronectin than on BSA. Anti-αV antibodies both alone and in combination with anti-α5 abolished the difference between fibronectin and BSA, although in the case of anti-αV alone this was due to an identical increase in cell proliferation and IL-8 secretion, whereas anti-αV and -α5 in combination abolished both. ^*P<0.05 vs untreated control.