FIG. 3.

Effect of convalescent-phase or acute-phase serum samples on IdeS activity towards myeloma IgG. Dilutions of patient serum samples were incubated with constant amounts of recombinant IdeS and ¹²⁵I-labeled myeloma IgG1 as the substrate. Sera from patients PT15 and PS2 had increases of >100% in ELISA index, and their patient PS5 showed a 19% increase in ELISA index. Inhibitions of IdeS activity in convalescent-phase serum samples at a 100-fold serum dilution were 83%, 83%, and 23%, respectively. Open symbols are acute-phase samples; filled symbols are convalescent-phase samples. Enzyme activity is relative to activity in serum depleted of IgG.