Complement Factor B (CFB) a component of the alternative pathway of complement activation. Upon activation of the alternative pathway, it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb. The active subunit Bb is a serine protease that associates with C3b to form the alternative pathway C3 convertase. The method of functional assay of CFB was tested in hemolysis assays. Two-fold dilute the recombinant human CFB with 0.9% NaCl, 2mmol/L MgCl2 ,and then add same volume of 1% rabbit erythrocyte (RaE) in 8mmol/L EDTA, the negative control only without MgCl2. All the samples incubated at 37℃. After 3 hours later, take 10μL supernatant and 90μL TMB incubated at 37℃ for 5-10 minutes. Finally, add 50μL stop solution to the wells and read at 450nm immediately. The results are shown in Figure 1. It was obvious that the minimal effective concentration of CFB is 0.3125μg/mL.(A) 1% rabbit erythrocyte (RaE) treated with 0.3125μg/mL CFB for 1h
(B) Negative control (1% RaE treated with 0.3125ug/mL CFB, 8mmol/L EDTA) without MgCl2.
Figure. The hemolysis effection of recombinant human CFB

Figure. The hemolysis activity of recombinant human CFB