Fig. 3.

Inhibition by small molecule antagonists of binding to ICAM-1 and induction of activation epitopes. (A and B) Inhibition of binding of soluble, multimeric ICAM-1 by LFA703 (A) or XVA143 (B). Binding of wild-type α_Lβ₂ K562 transfectants activated by preincubation with mAb CBR LFA-1/2 for 30 min or α_L-E310C/β₂-A210C transfectants was measured in medium containing 1 mM CaCl₂ and 1 mM MgCl₂.(C and D) Induction by XVA143 or Mn²⁺ of KIM127 (C) and m24 (D) epitopes. Transfectants in medium containing 1 mM CaCl₂/1 mM MgCl₂, 2 mM MnCl₂, and XVA143 as indicated were stained with KIM127 or m24 mAbs and subjected to immunofluorescence flow cytometry. Expression of activation-insensitive mAb TS2/4 was not affected by XVA143 or Mn²⁺ (data not shown).