unheated igiv at 10 mg/ml only marginally activated endogenous c3 in normal serum , had about a 5-fold lower affinity for 125i-c1q ( ki = 138 to 356 microm vs ki = 62.5 microm for isg ) , but was very similar in ability to isg on a weight basis in enhancing complement alternative pathway activity ( rch50 = 0.23 to 0.40 mg for igiv vs 0.17 mg for isg ) .
C0229671
serum
C0009498
complement