Chemicals and Drugs

Complement C3b

The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.

National Library of MedicineMedical Subject Headings2026

Structured Summary

Abstract

The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.

MeSH Record

Classification

Broader headings

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Related Concepts

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Drug Class

Pharmacological Action

MeSH Record

See Also

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Synonyms

10 entry terms
  • C3b Complement
  • Complement 3b
  • Complement Component 3b
  • C3b, Complement
  • Complement, C3b
  • Component 3b, Complement
  • C3bi
  • Inactivated C3b
  • iC3b
  • C3b, Inactivated

MeSH Record

Aspects Covered

29 allowable subheadings

Indexed with the subheadings administration & dosage, adverse effects, agonists, analysis, antagonists & inhibitors, biosynthesis, cerebrospinal fluid, chemical synthesis, chemistry, classification, deficiency, drug effects, economics, genetics, history, immunology, isolation & purification, metabolism, pharmacokinetics, pharmacology, physiology, poisoning, radiation effects, standards, supply & distribution, therapeutic use, toxicity, ultrastructure, urine.

MeSH Record

Indexing Annotation

/antag: consider COMPLEMENT C3B INACTIVATOR PROTEINS

MeSH Record

History Note

2006 (1978)

MeSH Record

Previous Indexing

  • Complement (1968-1974)
  • Complement 3 (1975-1977)

MeSH Hierarchy

Tree Number

  1. D12.776w.124w.486.274.250.260w

AMA Style

References

  1. National Library of Medicine. Complement C3b. Medical Subject Headings (MeSH). 2026. Unique ID D003179. http://id.nlm.nih.gov/mesh/2026/D003179
  2. Complement C3b. In: Wikipedia. https://en.wikipedia.org/wiki/C3b
  3. Complement C3b. In: Wikidata. https://www.wikidata.org/wiki/Q5008164