AL-57 IgG1 inhibits HA cell adhesion to keratinocytes. HA cells were labeled with calcein AM, preincubated with AL-57 IgG1, MHM24, or hIgG1 control, and added to a keratinocyte monolayer. After washing to remove unattached cells, remaining cells were photographed using fluorescence microscopy, and total fluorescence was measured using a fluorescence plate reader. (A) Representative pictures from samples treated without or with AL-57 IgG1, MHM24, or hIgG1 control at concentrations of 6.7 or 67 nM. (B) IC50 determination of AL-57 IgG1 and MHM24. Relative fluorescence units (RFU) from each sample were plotted as a function of the IgG concentration. From the representative plots shown here, IC50 values were calculated to be 1.2 nM for AL-57 IgG1 and 0.7 nM for MHM24 using SigmaPlot 8.0 software. (C) Summary of IC50 values from four independent experiments.