• Product nameAnti-C4b antibody
    See all C4b primary antibodies
  • Description
    Rabbit polyclonal to C4b
  • Tested applicationsSuitable for: ICC/IF, IHC-P, WBmore details
  • Species reactivity
    Reacts with: Human
    Predicted to work with: Chimpanzee, Non Human Primates
  • Immunogen

    Synthetic peptide conjugated to KLH derived from within residues 1100 - 1200 of Human C4b.

    (Peptide available as ab74629.)

  • Positive control
    • This antibody gave a positive signal in Human Plasma Total Protein


  • FormLiquid
  • Storage instructionsShipped at 4°C. Store at +4°C short term (1-2 weeks). Upon delivery aliquot. Store at -20°C or -80°C. Avoid freeze / thaw cycle.
  • Storage bufferPreservative: 0.02% Sodium Azide
    Constituents: 1% BSA, PBS, pH 7.4
  • Concentration information loading...
  • PurityImmunogen affinity purified
  • ClonalityPolyclonal
  • IsotypeIgG
  • Research areas

Associated products


Our Abpromise guarantee covers the use of ab66791 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
ICC/IF Use a concentration of 10 µg/ml.
IHC-P Use a concentration of 5 µg/ml. Perform heat mediated antigen retrieval before commencing with IHC staining protocol.
WB Use a concentration of 1 µg/ml. Detects a band of approximately 90 kDa (predicted molecular weight: 90 , 180 kDa).


  • FunctionC4 plays a central role in the activation of the classical pathway of the complement system. It is processed by activated C1 which removes from the alpha chain the C4a anaphylatoxin. The remaining alpha chain fragment C4b is the major activation product and is an essential subunit of the C3 convertase (C4b2a) and the C5 convertase (C3bC4b2a) enzymes of the classical complement pathway.
    Derived from proteolytic degradation of complement C4, C4a anaphylatoxin is a mediator of local inflammatory process. It induces the contraction of smooth muscle, increases vascular permeability and causes histamine release from mast cells and basophilic leukocytes.
  • Sequence similaritiesContains 1 anaphylatoxin-like domain.
    Contains 1 NTR domain.
  • Post-translational
    Prior to secretion, the single-chain precursor is enzymatically cleaved to yield the non-identical chains (alpha, beta and gamma). During activation, the alpha chain is cleaved by C1 into C4a and C4b, and C4b stays linked to the beta and gamma chains. Further degradation of C4b by C1 into the inactive fragments C4c and C4d blocks the generation of C3 convertase.
  • Cellular localizationSecreted.
  • Information by UniProt
  • Database links
  • Alternative names
    • Basic complement C4 antibody
    • C2B5 antibody
    • C3 and PZP-like alpha-2-macroglobulin domain-containing protein 3 antibody
    • C4b antibody
    • C4B1 antibody
    • C4B2 antibody
    • C4B3 antibody
    • CO4B_HUMAN antibody
    • Complement C4 gamma chain antibody
    • Complement component 4B antibody
    • CPAMD3 antibody
    see all

Anti-C4b antibody images

  • All lanes : Anti-C4b antibody (ab66791) at 1 µg/ml

    Lane 1 : Human Plasma Total Protein at 2 µg
    Lane 2 : Human Plasma Total Protein at 5 µg
    Lane 3 : Human Plasma Total Protein at 10 µg

    Goat polyclonal to Rabbit IgG - H&L - Pre-Adsorbed (HRP) at 1/3000 dilution

    Performed under reducing conditions.

    Predicted band size : 90 , 180 kDa
    Observed band size : 90 kDa (why is the actual band size different from the predicted?)

    Exposure time : 2 minutes
    We hypothesize that the 90 kDa band represents the C4b-A polypeptide chain, which is a cleavage product of C4b.
  • IHC image of ab66791 staining in human normal liver formalin fixed paraffin embedded tissue section, performed on a Leica BondTM system using the standard protocol F. The section was pre-treated using heat mediated antigen retrieval with sodium citrate buffer (pH6, epitope retrieval solution 1) for 20 mins. The section was then incubated with ab66791, 5µg/ml, for 15 mins at room temperature and detected using an HRP conjugated compact polymer system. DAB was used as the chromogen. The section was then counterstained with haematoxylin and mounted with DPX.

    For other IHC staining systems (automated and non-automated) customers should optimize variable parameters such as antigen retrieval conditions, primary antibody concentration and antibody incubation times.
  • ICC/IF image of ab66791 stained HepG2 cells. The cells were 4% formaldehyde (10 min) and then incubated in 1%BSA / 10% normal goat serum / 0.3M glycine in 0.1% PBS-Tween for 1h to permeabilise the cells and block non-specific protein-protein interactions. The cells were then incubated with the antibody (ab66791, 10µg/ml) overnight at +4°C. The secondary antibody (green) was ab96899 Dylight 488 goat anti-rabbit IgG (H+L) used at a 1/250 dilution for 1h. Alexa Fluor® 594 WGA was used to label plasma membranes (red) at a 1/200 dilution for 1h. DAPI was used to stain the cell nuclei (blue) at a concentration of 1.43µM.

References for Anti-C4b antibody (ab66791)

ab66791 has not yet been referenced specifically in any publications.

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