The B chain, but not the A chain, of Ricinus communis activates human complement.
Complement activation properties of ricin holotoxin, its A or B chain were assessed in two enzyme immunoassays (EIA). One was specific for C3 activation products and the other detected the terminal SC5b-9 complement complex (TCC) and thus determined activation of the initial and terminal part of the complement pathways, respectively. Ricin and its A and B chains were incubated with normal human serum or EDTA-serum. It was found that ricin B chain activated both the initial and terminal complement pathways in a time- and concentration-dependent fashion, whereas the A chain and the holotoxin did not.
Hetland
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Institute of Immunology and Rheumatology, National Hospital, Oslo, Norway.
Mollnes
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Garred
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P
D003167:Complement Activation; D003176:Complement C3 / Q000378:metabolism*; D003182:Complement C5 / Q000378:metabolism*; D050776:Complement C5b; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D007124:Immunoenzyme Techniques; D066298:In Vitro Techniques; D012276:Ricin / Q000494:pharmacology*
D003176:Complement C3; D003182:Complement C5; D050776:Complement C5b; D012276:Ricin; D004492:Edetic Acid