Flow cytometric analysis of 19.ek.Fc microspheres prepared with different concentrations of the 19.ek.Fc construct.

The 2-μm 19.ek.Fc microspheres were prepared with different concentrations of 19.ek.Fc. The 19.ek.Fc microspheres were treated with a fluorescently labeled mAb to PSGL-1 (KPL-1). Subsequently, the average fluorescence of each population of microspheres was determined via flow cytometric analysis. The average fluorescence intensity is plotted as a function of the concentration of 19.ek.Fc used to coat the microspheres. A coating concentration of 4 μg/mL appears to saturate the microspheres. The average fluorescence of the 19.ek.Fc microspheres generated with 0.04 μg/mL 19.ek.Fc was significantly higher than the average fluorescence of the ek.Fc microspheres generated with 0.04 μg/mL (38 vs 3, respectively).