Inhibition of IgE-mediated triggering of mast cells by complement-derived peptides interacting with the Fc epsilon RI.
Mucosal type mast cells, in contrast to the serosal type ones, do not respond to cationic agents, or to the complement-derived peptides C3a and C5a. Earlier we have found that while C3a does not activate the rat mucosal type mast cells (line RBL-2H3), it strongly inhibits the IgE-mediated triggering of these cells, by interfering with the Fc epsilon RI-initiated signaling pathway. In the present study we further investigated the mechanism of this process. It is shown, that C3a interacts with the beta-chain of the Fc epsilon RI complex. Binding of the complement peptide to the cells apparently causes a decrease in the proximity of the IgE-binding Fc epsilon RI. Investigating certain sequences of C3a we found that the inhibition is caused by the C-terminal sequences of the complement-peptide, ranging from positions 56 to 77 and also by a shorter sequence, ranging from positions 56 to 64. The inhibitory effect of these peptides was observed both in the case of RBL-2H3 cells and mouse bone marrow derived mast cells.
Department of Immunology, Loránd Eötvös University, Göd, Hungary. erdann@alfa.elte.hu
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Erdei
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Tóth
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Andrásfalvy
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Matkó
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Bene
Z
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Bajtay
A
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Ischenko
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Rong
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Pecht
D000595:Amino Acid Sequence; D000818:Animals; D001854:Bone Marrow Cells / Q000276:immunology; D002478:Cells, Cultured; D015926:Complement C3a / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D003165:Complement System Proteins / Q000737:chemistry*; D007073:Immunoglobulin E / Q000502:physiology*; D007166:Immunosuppressive Agents / Q000378:metabolism* / Q000494:pharmacology; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology; D011487:Protein Conformation; D051381:Rats; D017455:Receptors, IgE / Q000276:immunology / Q000378:metabolism*
D007166:Immunosuppressive Agents; D010455:Peptides; D017455:Receptors, IgE; D007073:Immunoglobulin E; D015926:Complement C3a; D003165:Complement System Proteins