Saturable binding of GM-CSF, IL-5, and IL-10 to IgG. Five to 9 batches of Gammagard (G), Sandoglobulin (S), and Nordimmun (N) were tested in parallel at 4 mg/mL IgG and 0.1 to 0.2 ng/mL¹²⁵I-cytokines: E coli-derived GM-CSF and IL-10, and Sf-21 cell-derived IL-5. The results are shown as median percentage (ranges) of displaceable binding divided by the total amount of ¹²⁵I-cytokine in the assay. The background binding was <3%.