Blocking cell surface tTG inhibits migration of M-CSF–treated monocytes on Fn and the 42-kd Fn fragment.

Human peripheral blood monocytes (5 × 10⁴) in serum-free AIM-V medium containing 0.5% BSA were stimulated for 4 hours with 5 ng/mL M-CSF and then placed for 4 hours at 37°C into upper chambers of Transwells (Costar) where undersurface of the inserts was precoated with Fn (■) or its 42-kd fragment (▪). Then 125 ng/mL MCP-1 was added to lower chambers. Before adding to the Transwells, monocytes were preincubated for 1 hour with control nonimmune IgG, function-blocking polyclonal anti-tTG antibody, anti-tTG mAb 4G3, or blocking mAbs against β₁-, β₂-, or β₃-integrins. The antibodies were kept in the medium during the assay. Shown are the means of 3 separate experiments performed in duplicate.