XVA143, an α/β I-like allosteric antagonist, effectively blocks LFA-1-dependent firm adhesion while simultaneously increasing adhesion under shear flow and rolling conditions, both in vitro and in vivo.

XVA143, at a concentration of 1 μM, effectively eliminates the interaction between ICAM-1 and LFA-1 in the presence of Mn^2+ and Mg^2+/EGTA environments, displaying no agonistic activity. Additionally, it positively influences the rolling mechanism of the α_L-E310A β_2 mutant by facilitating the extension of α_L, thereby restoring its function. In cell viability assays utilizing K562 cells at concentrations of 0, 0.2, 0.5, and 1 μM, XVA143 demonstrated varied potency, being most effective against the weakest activator (2 mM Mg^2+/1 mM EGTA, IC_50 approximates 10^-3 nM) and less effective against the stronger activator (1 mM Mn^2+, IC_50 approximates 10^-3 nM). Furthermore, when tested on wild-type murine lymphocytes at a concentration of 100 μM, XVA143 was found to significantly increase the rolling fraction by 50% in comparison to vehicle-treated control cells, moving from 27±5% to 41±7%.