ArticleImmunology2001
Streptococcal inhibitor of complement (SIC) inhibits the membrane attack complex by preventing uptake of C567 onto cell membranes.
Article in Immunology, 2001. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 47 papers.
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Who cites it
47 citing papers in PubMed, 123 citations in OpenAlex.
- Molecular mechanism of complement interference by Streptococcus pyogenes nuclease A.Communications biology · 2026Article
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- Characterization of a novelmBio · 2025Article
- Scabies.Nature reviews. Disease primers · 2024Review
- Interplay between group AMicrobiology and molecular biology reviews : MMBR · 2024Review
- Mechanisms that potentially contribute to the development of post-streptococcal glomerulonephritis.Pathogens and disease · 2024Review
- Methods to Analyze the Contribution of Complement Evasion Factor (CEF) to Streptococcus pyogenes Virulence.Methods in molecular biology (Clifton, N.J.) · 2023Article
- Microbial evasion of the complement system: a continuous and evolving story.Frontiers in immunology · 2023Review
- Article
- Innate immunity and microbial dysbiosis in hidradenitis suppurativa - vicious cycle of chronic inflammation.Frontiers in immunology · 2022Review
- Vaccine-induced, but not natural immunity, against the Streptococcal inhibitor of complement protects against invasive disease.NPJ vaccines · 2021Article
- Complete genome sequences of Streptococcus pyogenes type strain reveal 100%-match between PacBio-solo and Illumina-Oxford Nanopore hybrid assemblies.Scientific reports · 2020Article
- Streptococcus pyogenes genes that promote pharyngitis in primates.JCI insight · 2020Article
- Monoclonal Antibodies Capable of Inhibiting Complement Downstream of C5 in Multiple Species.Frontiers in immunology · 2020Article
- Remarkable Genome Stability among emm1 Group A Streptococcus in Belgium over 19 Years.Genome biology and evolution · 2019Article
- Group A streptococcus endocarditis in children: 2 cases and a review of the literature.BMC infectious diseases · 2019Review
- Toxins and Superantigens of Group A Streptococci.Microbiology spectrum · 2019Article
- Catch Me if You Can: Streptococcus pyogenes Complement Evasion Strategies.Journal of innate immunity · 2019Review
- Complement and Bacterial Infections: From Molecular Mechanisms to Therapeutic Applications.Journal of innate immunity · 2018Review
- Protein SIC Secreted fromFrontiers in immunology · 2018Observational
Corrections and comments
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Authors and funding
6 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Streptococcal inhibitor of complement (SIC) was first described in 1996 as a putative inhibitor of the membrane attack complex of complement (MAC). SIC is a 31 000 MW protein secreted in large quantities by the virulent Streptococcus pyogenes strains M1 and M57, and is encoded by a gene which is extremely variable. In order to study further the interactions of SIC with the MAC, we have made a recombinant form of SIC (rSIC) in Escherichia coli and purified native M1 SIC which was used to raise a polyclonal antibody. SIC prevented reactive lysis of guinea pig erythrocytes by the MAC at a stage prior to C5b67 complexes binding to cell membranes, presumably by blocking the transiently expressed membrane insertion site on C7. The ability of SIC and clusterin (another putative fluid phase complement inhibitor) to inhibit complement lysis was compared, and found to be equally efficient. In parallel, by enzyme-linked immunosorbent assay both SIC and rSIC bound strongly to C5b67 and C5b678 complexes and to a lesser extent C5b-9, but only weakly to individual complement components. The implications of these data for virulence of SIC-positive streptococci are discussed, in light of the fact that Gram-positive organisms are already protected against complement lysis by the presence of their peptidoglycan cell walls. We speculate that MAC inhibition may not be the sole function of SIC.
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