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Complement C3 Antibody (11H9) - BSA Free

Catalog # NB200-540 | Novus Biologicals a Bio-Techne Brand

Key Product Details

Validated by

Biological Validation

Species Reactivity

Mouse, E. coli


CyTOF-ready, Flow (Intracellular), Flow Cytometry, Immunoassay, Immunocytochemistry/ Immunofluorescence, Immunohistochemistry, Immunohistochemistry-Frozen, Immunohistochemistry-Paraffin, Immunoprecipitation



Antibody Source

Monoclonal Rat IgG2A Clone # 11H9


BSA Free


1.0 mg/ml

Product Summary for Complement C3 Antibody (11H9) - BSA Free


This Complement C3 Antibody (11H9) was developed against C57BL/6 thymocytes saturated with rat anti-Thy-1 monoclonal antibody of IgG2b subclass (RmT1).

Reactivity Notes

Use in Mouse reported in scientific literature (PMID:34433493). Use in E. coli reported in scientific literature (PMID:32422907).




Mouse Complement C3 and its activation products, C3b, iC3b, C3d and C3dg







Theoretical MW

187 kDa.
Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.

Scientific Data Images for Complement C3 Antibody (11H9) - BSA Free

Flow (Intracellular): Complement C3 Antibody (11H9) [NB200-540] - An intracellular stain was performed on RAW 246.7 cells with Complement C3 (11H9-3-2) antibody NB200-540 (blue) and a matched isotype control NBP2-31382 (orange). Cells were either treated with 3uM Monensin for 3 hours to block the secretion of Complement C3 (B) or grown in normal media (A). Cells were fixed with 4% PFA and then permeablized with 0.1% saponin. Cells were incubated in an antibody dilution of 2 ug/mL for 30 minutes at room temperature, followed by mouse F(ab)2 IgG (H+L) PE-conjugated secondary antibody (F0102B, R&D Systems).
Immunocytochemistry/Immunofluorescence: Complement C3 Antibody (11H9) [NB200-540] - C3 protein fragments deposited on kidney cells of MPL-lpr mouse. Staining with antibody 11H9. Glomerular staining pattern. Fixation in 4% paraformaldehyde in PBS pH 7.4. Vibratome sections of 4 um. Pretreated with 3% hydrogen peroxide for 20 min to quench endogenous peroxidases. Microwaved in antigen unmasking solution for 2-5 minutes as antigen retrieval.
Immunohistochemistry-Paraffin: Complement C3 Antibody (11H9) [NB200-540] - Complement C3 protein in a FFPE tissue section of mouse liver using 1:100 dilution of Complement C3 antibody (clone 11H9) NB200-540. Weak but distinct membrane-cytoplasmic immunopositivity was observed in hepatocytes and few cells developed punctate membrane staining.

Applications for Complement C3 Antibody (11H9) - BSA Free

Recommended Usage

Flow (Intracellular)

1 ug/ml

Flow Cytometry

1 ug/ml


0.5 ug/well in PBS

Immunocytochemistry/ Immunofluorescence









Please Note: Optimal dilutions of this antibody should be experimentally determined.

Reviewed Applications

Read 2 reviews rated 4.5 using NB200-540 in the following applications:

Published Applications

Read 30 publications using NB200-540 in the following applications:

Formulation, Preparation, and Storage


Protein G purified




BSA Free


0.02% Sodium Azide


1.0 mg/ml


The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.

Stability & Storage

Store at 4C short term. Aliquot and store at -20C long term. Avoid freeze-thaw cycles.

Background: Complement C3

The complement system, or complement cascade, is a part of the innate immune system that assists in defense against pathogens (1-3). Complement C3, also called C3 or C3 protein, is one of nine complement proteins and is the main component of the complement system which is composed of over 30 soluble and membrane-bound proteins (1,4). The complement cascade consists of three main pathways: the classical, the lectin, and the alternative, all of which converge into a common pathway involving C3 cleavage by C3-convertases (1-6). Human Complement C3 is synthesized as a protein of 1663 amino acids (aa) in length with a theoretical molecular weight of ~185 kDa (5). Complement C3 is the most prevalent human complement protein in the serum, with a concentration of 1.2 mg/mL, and is predominantly produced by hepatocytes in the liver, but is also synthesized by blood cells and epithelial cells (3,5). Furthermore, the structure of C3 is comprised of an alpha-chain (110 kDa) and a beta-chain (75 kDa) linked by a disulfide bond (5). Cleavage of inactive C3 by C3-convertases produces active C3a, which functions as a mediator of inflammation, and C3b, which is an opsonin (1-4). In addition to amplification of complement response, C3 fragments serve multiple additional functions including chemotaxis, phagocytosis, adhesion, and immune modulation (3). Complement C3 serves dual purposes where it is involved in pathogenesis and immunity but, conversely, cellular damage results from unregulated C3 activation (5).

Both elevated levels and reduced levels of Complement C3 has been implicated in diseases pathologies (6). Deficiency in Complement proteins can result in autoimmune disorders including systemic lupus erythematosus, which is more often associated with C1 or C4 deficiency and only rarely with C3 deficiency (6). However, C3 deficiency typically results in increased risk of recurrent bacterial infections and glomerulonephritis, characterized by inflammation of the filtering glomeruli in the kidneys (6). Additionally, elevated levels of C3a and C4a is seen in patients with antiphospholipid antibody syndrome (6). Serum levels of C3 are also higher in rheumatoid arthritis cases (6). The complement system has become a target for drugs and therapeutics aimed at modulating innate immunity (7). For instance, compstatin is a peptide that binds to C3, inhibiting convertase activity and cleavage and can be used to treat diseases associated with uncontrolled C3 activation (7). C3-inhibitors and other complement inhibitors are a promising drug candidate for treatment of many diseases (7).


1. Mathern, D. R., & Heeger, P. S. (2015). Molecules Great and Small: The Complement System. Clinical Journal of the American Society of Nephrology: CJASN.

2. Merle, N. S., Church, S. E., Fremeaux-Bacchi, V., & Roumenina, L. T. (2015). Complement System Part I - Molecular Mechanisms of Activation and Regulation. Frontiers in Immunology.

3. Ricklin, D., Reis, E. S., Mastellos, D. C., Gros, P., & Lambris, J. D. (2016). Complement component C3 - The "Swiss Army Knife" of innate immunity and host defense. Immunological Reviews.

4. Merle, N. S., Noe, R., Halbwachs-Mecarelli, L., Fremeaux-Bacchi, V., & Roumenina, L. T. (2015). Complement System Part II: Role in Immunity. Frontiers in Immunology.

5. Sahu, A., & Lambris, J. D. (2001). Structure and biology of complement protein C3, a connecting link between innate and acquired immunity. Immunological Reviews.

6. Vignesh, P., Rawat, A., Sharma, M., & Singh, S. (2017). Complement in autoimmune diseases. Clinica Chimica Acta; International Journal of Clinical Chemistry.

7. Mastellos, D. C., Yancopoulou, D., Kokkinos, P., Huber-Lang, M., Hajishengallis, G., Biglarnia, A. R., Lupu, F., Nilsson, B., Risitano, A. M., Ricklin, D., & Lambris, J. D. (2015). Compstatin: a C3-targeted complement inhibitor reaching its prime for bedside intervention. European Journal of Clinical Investigation.

Alternate Names

Acylation Stimulating Protein, acylation-stimulating protein cleavage product, AHUS5, ARMD9, ASP, C3, C3 and PZP-like alpha-2-macroglobulin domain-containing protein 1, C3a, C3a anaphylatoxin, C3adesArg, C3b, C3bc, C3-beta-c, complement C3, Complement C3 alpha chain, Complement C3 beta chain, Complement C3b alpha' chain, Complement C3c alpha' chain fragment 1, Complement C3c alpha' chain fragment 2, Complement C3d fragment, Complement C3dg fragment, Complement C3f fragment, Complement C3g fragment, complement component 3, complement component C3, complement component C3a, complement component C3b, CPAMD1, EC, epididymis secretory sperm binding protein Li 62p, HEL-S-62p, prepro-C3

Entrez Gene IDs

12266 (Mouse)

Gene Symbol



Product Documents for Complement C3 Antibody (11H9) - BSA Free

Certificate of Analysis

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Product Specific Notices for Complement C3 Antibody (11H9) - BSA Free

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Primary Antibodies are guaranteed for 1 year from date of receipt.



View specific protocols for Complement C3 Antibody (11H9) - BSA Free (NB200-540):

Protocol for Flow Cytometry Intracellular Staining
Sample Preparation.
1. Grow cells to 60-85% confluency. Flow cytometry requires between 2 x 105 and 1 x 106 cells for optimal performance.
2. If cells are adherent, harvest gently by washing once with staining buffer and then scraping. Avoid using trypsin as this can disrupt certain epitopes of interest. If enzymatic harvest is required, use Accutase, Collagenase, or TrypLE Express for a less damaging option.
3. Reserve 100 uL for counting, then transfer cell volume into a 50 mL conical tube and centrifuge for 8 minutes at 400 RCF.
a. Count cells using a hemocytometer and a 1:1 trypan blue exclusion stain to determine cell viability before starting the flow protocol. If cells appear blue, do not proceed.
4. Re-suspend cells to a concentration of 1 x 106 cells/mL in staining buffer (NBP2-26247).
5. Aliquot out 100 uL samples in accordance with your experimental samples.

Tip: When cell surface and intracellular staining are required in the same sample, it is advisable that the cell surface staining be performed first since the fixation and permeabilization steps might reduce the availability of surface antigens.

Intracellular Staining.
Tip: When performing intracellular staining, it is important to use appropriate fixation and permeabilization reagents based upon the target and its subcellular location. Generally, our Intracellular Flow Assay Kit (NBP2-29450) is a good place to start as it contains an optimized combination of reagents for intracellular staining as well as an inhibitor of intracellular protein transport (necessary if staining secreted proteins). Certain targets may require more gentle or transient permeabilization protocols such as the commonly employed methanol or saponin-based methods.
Protocol for Cytoplasmic Targets:
1. Fix the cells by adding 100 uL fixation solution (such as 4% PFA) to each sample for 10-15 minutes.
2. Permeabilize cells by adding 100 uL of a permeabilization buffer to every 1 x 106 cells present in the sample. Mix well and incubate at room temperature for 15 minutes.
a. For cytoplasmic targets, use a gentle permeabilization solution such as 1X PBS + 0.5% Saponin or 1X PBS + 0.5% Tween-20.
b. To maintain the permeabilized state throughout your experiment, use staining buffer + 0.1% of the permeabilization reagent (i.e. 0.1% Tween-20 or 0.1% Saponin).
3. Following the 15 minute incubation, add 2 mL of the staining buffer + 0.1% permeabilizer to each sample.
4. Centrifuge for 1 minute at 400 RCF.
5. Discard supernatant and re-suspend in 100 uL of staining buffer + 0.1% permeabilizer.
6. Add appropriate amount of each antibody (eg. 1 test or 1 ug per sample, as experimentally determined).
7. Mix well and incubate at room temperature for 30 minutes- 1 hour. Gently mix samples every 10-15 minutes.
8. Following the primary/conjugate incubation, add 1-2 mL/sample of staining buffer +0.1% permeabilizer and centrifuge for 1 minute at 400 RCF.
9. Wash twice by re-suspending cells in staining buffer (2 mL for tubes or 200 uL for wells) and centrifuging at 400 RCF for 5 minutes. Discard supernatant.
10. Add appropriate amount of secondary antibody (as experimentally determined) to each sample.
11. Incubate at room temperature in dark for 20 minutes.
12. Add 1-2 mL of staining buffer and centrifuge at 400 RCF for 1 minute and discard supernatant.
13. Wash twice by re-suspending cells in staining buffer (2 mL for tubes or 200 uL for wells) and centrifuging at 400 RCF for 5 minutes. Discard supernatant.
14. Resuspend in an appropriate volume of staining buffer (usually 500 uL per sample) and proceed with analysis on your flow cytometer.

Immunohistochemistry-Paraffin Embedded Sections

Antigen Unmasking:
Bring slides to a boil in 10 mM sodium citrate buffer (pH 6.0) then maintain at a sub-boiling temperature for 10 minutes. Cool slides on bench-top for 30 minutes (keep slides in the sodium citrate buffer at all times).

1. Wash sections in deionized water three times for 5 minutes each.
2. Wash sections in PBS for 5 minutes.
3. Block each section with 100-400 ul blocking solution (1% BSA in PBS) for 1 hour at room temperature.
4. Remove blocking solution and add 100-400 ul diluted primary antibody. Incubate overnight at 4 C.
5. Remove antibody solution and wash sections in wash buffer three times for 5 minutes each.
6. Add 100-400 ul HRP polymer conjugated secondary antibody. Incubate 30 minutes at room temperature.
7. Wash sections three times in wash buffer for 5 minutes each.
8. Add 100-400 ul DAB substrate to each section and monitor staining closely.
9. As soon as the sections develop, immerse slides in deionized water.
10. Counterstain sections in hematoxylin.
11. Wash sections in deionized water two times for 5 minutes each.
12. Dehydrate sections.
13. Mount coverslips.