Engagement of β2 integrins at the monocyte cell surface stimulates NF-κB DNA-binding activity.
(A) Nonadherent monocytes were left untreated (lane 1) or stimulated for 30 and 60 minutes with anti-CD11a (BU17, 5 μg/mL; lanes 2 and 3), anti-CD11b (ICRF44, 5 μg/mL; lanes 4 and 5), or anti-CD11c (BU15, 5 μg/mL; lanes 6, 7) mAbs. Nuclear extracts were prepared and NF-κB DNA-binding activity was assessed in bandshift experiments. Lane 8 shows the migration of the radiolabeled κB probe in the absence of nuclear extracts. (B) Nonadherent monocytes were incubated for 30 minutes with medium alone (lane 1), MBP-CD23 (2 μg/mL; lane 2), ZZ–P selectin (5 μg/mL; lane 3), or ZZ-CD23 (5 μg/mL; lane 4). NF-κB DNA-binding activity was measured in 5 μg nuclear extracts in bandshift experiments. The specificity of the DNA-binding complex was analyzed by incubation with a 50- and 100-fold excess of unlabeled κB probe (lanes 5 and 6) or a 100-fold excess of NF-1 oligonucleotide (lane 7) under the conditions depicted in lane 4. Results are the most representative of 4 distinct experiments.
