Gene SymbolC8B
Full NameComplement Component 8 Beta Chain
Chromosomal Location2p13.2
Ensembl IDENSG00000100031
Associated DiseasesComplement Deficiency, Neisseria Infections
The C8B gene encodes the beta chain of complement component 8 (C8β), which pairs with C8A (alpha chain) and C8G (gamma chain) to form the complete C8 complex. The gene is located on chromosome 2p13.2 and encodes a protein of 579 amino acids [1].
The C8 complex is essential for the lytic activity of the membrane attack complex (MAC). The beta chain forms the structural core of the C8 complex and is critical for its function in pore formation [2].
The C8 beta chain functions as:
- Complex Formation: Pairs with C8A and C8G to form the heterotrimeric C8 complex
- Membrane Insertion: Facilitates insertion of the C5b-8 complex into target cell membranes
- C9 Polymerization: Provides a platform for C9 polymerization to complete MAC formation
- Lytic Activity: Essential for the cytolytic activity of the MAC
- C8B Deficiency: Leads to increased susceptibility to Neisseria infections
- Hereditary Deficiency: Rare autosomal recessive condition
- MAC-mediated Neurotoxicity: Sublytic MAC deposition may contribute to neuronal injury
- Glial Activation: MAC can activate microglia and astrocytes
- Liver: Primary site of synthesis
- Brain: Low expression in neural tissues
- Kaufman et al., Molecular cloning of C8B (1991)
- Nishikawa et al., C8 beta chain structure (1992)
- Würzner et al., C8 deficiency types (1995)
- Miller et al., C8 beta and susceptibility to infection (1988)
- Haddad et al., C8 beta deficiency (2006)
- Baran et al., C8 beta and immune function (2010)
- Riley et al., Complement activation (2002)
- Frank et al., Terminal complement pathway (1995)