Fig 6. Dose effect of THP concentration on cofactor activity.

(A) 8% SDS-PAGE silver-stained gel of ß-mercaptoethanol-reduced samples. All lanes were loaded with 125 ng C3b and 150 ng CFI. Samples in all lanes except that of Lane A were incubated at 37°C for 4 h. Lanes C → I contained samples with varying concentrations of a male THP sample (from 10 μg to 0.25 μg). Starred arrows indicate the degradation products of C3b. (B) Plot of THP quantity versus intensity of band ratio obtained after Image J analysis of the intensity of the C3bα₆₂ fragment versus the C3b ß-chain in each lane minus the background cleavage present in Lane B.