Further evidence for dilution-dependent dissociation of C1q in human serum.
Dissociation of the C1q subcomponent in native C1 upon dilution was reexamined by using ultracentrifugation in a sucrose gradient and high performance liquid chromatography system with a size exclusion column for separating the dissociated C1q fractions. The antigenic content of C1q in each fraction was detected by ELISA and Western blotting; binding to erythrocyte antibody was also determined. The results confirmed a previous claim that C1q in native C1 dissociated as a function of dilution: up to 14.5% of C1q antigen was in the low molecular weight form (approximate S value: 4-5). Commercial preparations of purified C1q also contained C1q antigen in the low molecular weight form.
Hosoi
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S
Laboratory of Immunobiology, National Cancer Institute, Frederick, MD.
Borsos
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T
D002499:Centrifugation, Density Gradient; D002851:Chromatography, High Pressure Liquid; D003166:Complement Activating Enzymes / Q000302:isolation & purification / Q000378:metabolism*; D003172:Complement C1 / Q000302:isolation & purification / Q000378:metabolism*; D015922:Complement C1q; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances
D003172:Complement C1; D046911:Macromolecular Substances; D015922:Complement C1q; D003166:Complement Activating Enzymes