Inhibition of human and mouse complement-dependent hemolytic activity by mouse fibronectin.
Not only does mouse complement (C) have low hemolytic activity, but mouse serum has an inhibiting effect on hemolysis by human C. To purify and identify the putative mouse serum factor inhibiting human C activity, a sequential procedure of fractionated precipitation by PEG, followed by chromatographies with a heparin-Sepharose column, a phenyl-Sepharose column, a Protein G column, and a gel-filtration column was performed. The amino acid sequence analyses of two polypeptides obtained by digestion of the purified serum factor with TPCK-trypsin revealed that it was mouse fibronectin (FN). Highly purified mouse FN, but not human FN, has an inhibiting effect on human C-dependent hemolysis. Moreover, the hemolysis of sensitized rabbit erythrocytes by mouse C was also inhibited by the addition of mouse FN in a dose-dependent fashion, but not by the addition of human FN. These results suggest that FN is the putative internal C inhibitor in the mouse system.
Department of Clinical Laboratory Medicine, Ehime University School of Medicine, Japan. hitsumot@m.ehime-u.ac.jp
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Hitsumoto
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Okada
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Makino
D000818:Animals; D015941:Complement Hemolytic Activity Assay; D003169:Complement Inactivator Proteins / Q000302:isolation & purification / Q000494:pharmacology / Q000502:physiology*; D005353:Fibronectins / Q000097:blood / Q000302:isolation & purification / Q000494:pharmacology / Q000502:physiology*; D006461:Hemolysis / Q000276:immunology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D011817:Rabbits; D012756:Sheep; D013045:Species Specificity
D003169:Complement Inactivator Proteins; D005353:Fibronectins