C1-INH Dpl (NEW)

Product Description

Normal human serum was depleted of C1-Inhibitor (C1-INH) by immunoaffinity chromatography. The product is tested for the absence of C1-INH by double immunodiffusion. C1-INH is a regulator of the classical pathway of complement activation. The protease inhibitor C1-INH prevents the spontaneous activation of complement and limits consumption of C2 and C4 by rapidly inactivating C1r, C1s and MASP2 enzymes. The process of making C1-INH depleted serum (C1-INH Dpl) results in the activation of classical pathway components C2 and C4 and hence their consumption. Thus C1-INH Dpl does not possess a functional classical pathway of complement.

In the absence of C1-INH, initial assays indicated that a fully functional classical pathway of complement could be restored by adding purified C2 and C4 proteins at their respective normal serum concentrations to the C1-INH Dpl. However, this was not reproducible. Additional CH50 assays conducted exhibited a lot of variability with < 35% restoration of the CH50 activity. Increasing the C4 and C2 concentration improved the activity but did not restore it to > 80%. The inconsistency in the CH50 assays suggested variability in C4 and C2 activation and hence in their consumption. Since C1s enzyme activates C4 and C2, the results implied that in the absence of C1-INH, depending on how the C1-INH-Dpl was handled for the assays (number of freeze/thaw cycles, thawing time, etc.) activation of C1s proenzyme by C1r to its enzymatic form had occurred in the depleted serum, thus generating C1s enzyme, the amount of which varied from assay to assay. For this reason, the C1-INH Dpl should not be subjected to more than one freeze/thaw cycle and should be kept in an ice-water bath at 0 ^oC for usage.

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