Deviated lysis (d.l.), as described by Rother et al. (Z. Immun.-Forsch. Bd. 148:172, 1974), is the ability of activated complement, either on the surface of the activating particle or in the fluid phase, to lyse nonsensitized target cells in the presence of EDTA. We wish to report experiments conducted to characterize the active principle responsible for this activity. D.1. activity was generated by incubating NHS with inulin for 10 to 20 min at 37°C. The reaction was terminated by the addition of EDTA (10 mM final concentration) and centrifugation to separate pellet-associated and fluid phase activities, which were assayed for their ability to lyse chicken erythrocytes (ChE) in GVB-10 mM EDTA (GVBE).
Characterization of the sucrose-stabilized fluid phase d.l. activity revealed a major peak possessing a m.w. of 250–350,000 daltons and an S-rate of 14 to 16 S as determined by chromatography with Bio-Gel A-0.5 M and sucrose density gradient ultracentrifugation. D.1. activity present in column and gradient fractions was completely inhibited by monospecific antisera to properdin, factor B or C3 but not by anti-C4.