Fig. 2. Effects of heparitinase on binding of III₁₃ and III_1c to cell layers. Human fibroblasts were grown as described in the legend to Fig. 1. Cell layers were pretreated for 2 hours with increasing amounts of heparitinase I. The monolayers were then incubated with 20 µM of either the III_1c module or III₁₃ module for 2 hours in the continued presence of heparitinase I. Wells were then processed to determine the amount of recombinant protein associated with the cell layers using a mAb to the His-tag. The data points represent the average of triplicate determinations, and error bars indicate the standard error of means. The graph represents one of three experiments performed. Loss of heparan sulfate in response to hepartinase was assessed by ELISA using an antibody against heparan sulfate (insert).