Fig. 2.

Influence of patient’s and control Ig on stability of C3 and C5 classical convertases. In order to assess the influence of total Ig fraction purified from patient seven plasma on classical C3 and C5 convertase, Ig preparations were mixed with 1 % C3-depleted or C5-depleted serum, respectively, and incubated with sensitized sheep erythrocytes for an indicated period of time. Samples were wzashed and incubated with guinea pig serum diluted in 40 mM EDTA-GVB buffer, which disabled de novo convertase formation but allowed development of lytic sites only from pre-existing convertases. Percentage of lysis measured at 405 nm was referred to the equal amount of sensitized erythrocytes lysed with equal volume of water. Ig preparation from NHS was used as a negative control. Data were collected from three independent experiments; statistical significance was assessed by two-way ANOVA