Competitive inhibition of fluid-phase ¹²⁵I-mPS binding to neutrophils by unlabeled mPS, sPS, or Lec-EGF. Neutrophils (1.5 × 10⁶ cells; final volume, 500 μL) were incubated with a near-saturating concentration of ¹²⁵I-mPS (4.2 nmol/L) and increasing concentrations of unlabeled mPS, sPS, or Lec-EGF for 1 hour at 4°C. Specific binding was determined as described in the Materials and Methods. Each point represents the mean ± standard deviation (SD) of triplicate assays in a representative experiment. Similar results were obtained in three other experiments using different preparations of unlabeled fluid-phase mPS, sPS, and Lec-EGF.