Product Description

C3/FB-Depleted Serum is normal humanserum in which C3 and factor B(fB) have been removed by immunoaffinity chromatography.The product istested for the absence of C3 and factor B activity by testing classical and alternative pathway function and for the absence of C3 andfactorB proteins by double immunodiffusion. The C3/FB-depleted serumis certified to exhibitless than 5% classical pathway and alternativepathway activities. A functionalclassical pathway can be reconstitutedby addition of purified C3 protein (1.3mg/mL) whereas a functionalalternative pathway can be reconstituted byaddition of purified C3protein (1.3 mg/mL) and factor B protein (0.2 mg/mL)indicating thatall other complement components necessary for classical andalternativepathway activation are present. After reconstitution with C3 (1.3mgC3/mL) the C3/FB-Depleted Serum is certified to possess a functional classical pathway for complement activation whereas after reconstitutionwithC3 (1.3 mg C3/mL) and factor B (0.2 mg/mL), the product iscertified to possessa functional alternative pathway for complementactivation (Morgan, B.P.(2000); Dodds, A.W. and Sim, R.B. (1997)).Although a functional lectin pathwayshould also be reconstituted bythe addition of similar concentrations of C3,the function of thispathway is not tested.

Note that there is a weak C3by-passmechanism whereby the convertase C4b,C2a is able to activate C5(Rawal, N.& Pangburn, M.K. 2003) and form C5b-9 complexes capableof causing lowgrade lysis. This system of C5 activation is functionalin both the classicaland the lectin pathways and is approximately1000-fold less active than in thepresence of C3.

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