Beta chain deficiency in three patients with dysfunctional C8 molecules.
Structural and functional studies were performed on a dysfunctional C8 molecule present in the serum of two siblings and an unrelated individual. The C8 in these three sera exhibited a pattern of partial immunologic identity with C8 in normal serum but was devoid of functional activity. The C8 was immunoprecipitated from the three sera and from a control serum with an antihuman C8 antiserum and analyzed by SDS-PAGE using highly purified human C8 as a reference. A selective absence of a band of 62,000 mol. wt was observed in the immunoprecipitates from the sera containing dysfunctional C8. Experiments performed with the purified alpha-gamma and beta subunits showed that the hemolytic activity of the C8 deficient sera could be reconstituted by the addition of the beta chain but not the alpha-gamma dimer. Binding of the dysfunctional C8 to C567 was excluded by the following observations: (1) EAC1-7 treated with the C8 deficient sera and then washed could not be lysed after the addition of the beta subunit and C9; and (2) the abnormal molecules did not interfere with the consumption of normal C8 by the soluble complex SC5b-7.
D001667:Binding, Competitive; D003185:Complement C8 / Q000037:antagonists & inhibitors / Q000172:deficiency* / Q000276:immunology* / Q000502:physiology; D003165:Complement System Proteins / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006461:Hemolysis; D006801:Humans
D003185:Complement C8; D003165:Complement System Proteins