Human Complement, Pooled
Human serum collected to preserve complement activity, 0.2 µm filtered, aliquoted, and frozen.Often used for serum bactericidal assays (SBA), complement-dependent cytotoxicity (CDC) assays and alternative pathway (AH50) assays.
Specifications
Release criteria
Lead time on this item is currently: 2-4 Weeks

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Product Overview
| Species: | Human |
|---|---|
| Product Types: | Complement |
| Source: | OTC Serum (Complement Preserved) |
| Pooling: | Pooled |
| Donor Sex: | Mixed |
| Physical State: | Frozen Liquid |
| Application Notes: | Suitable as a source of human complement proteins. Complement components are extremely heat-sensitive; for best results, thaw complement on ice or in a cold water bath. Aliquots may be made and frozen at -70°C or below. Avoid multiple freeze-thaw cycles. When a working aliquot is thawed, do not re-freeze remaining complement, but discard it. |
| Testing: | CH50: >100 Serum tested negative for infectious disease per FDA guidelines. |
| Storage Conditions: | -70°C or below |
| Shipping Conditions: | Dry ice |
| Packaging: | Cryovial, Poly bottle |
| Expiration: | 1 year from date of receipt when stored continuously at -70°C or below; avoid repeated freeze/thaw |
Product Applications
- Serum bactericidal assay
- Opsonophagocytic assay
- Complement-dependent cytotoxicity
- Hemolytic complement assay
- Complement fixation test
- Alternative pathway assay
- Complement deposition assay
- Virus neutralization assay
- ELISA
- Immunohistochemistry
Cited in Ali 2026, Shaughnessy 2020
Documents & Datasheets
Frequently Asked Questions
How does freezing and thawing affect complement activity?
Should I choose lyophilized or frozen liquid complement?
What is complement activity (CH50 / hemolytic titer) and how is it tested?
Should I use human, rabbit, or guinea pig complement for my application?
Work backwards from the readout. Complement regulators are host-specific, so the complement source is part of the assay method, not a preference.
- Antibody-depleted human complement for the hSBA (serogroup B meningococcus and gonococcus; correlate hSBA ≥ 1:4). Neisseria recruits human factor H, which rabbit and guinea pig factor H cannot replace, and the donor antibodies in native human serum would kill the target on their own.
- Baby rabbit complement for the rSBA (serogroups A, C, W and Y; correlate rSBA ≥ 1:8) and for pneumococcal OPA/MOPA, which was standardized on it.
- Adult rabbit complement for complement-dependent cytotoxicity and HLA crossmatching, the classical cell-lysis source.
- Guinea pig complement where potency per volume is the point: CH50 titration, complement fixation and the vibriocidal assay.
When the model animal's own cascade is the readout, use matched-species complement. Mouse, rat, pig, canine, cynomolgus, goat and hamster complement are available on request through our custom quote form.
For what the research literature actually uses, by pathogen and assay, see which complement source for which assay.
What concentration of human complement should I use?
Why am I seeing non-specific killing in my opsonophagocytic killing assay?
• Run the assay with a new aliquot of bacteria, in case the original was compromised in a way that made it easier to kill.
• Use a different bacterial strain to see if you can replicate the finding.
• Test a new HL60 cell preparation, preferably at a higher or lower passage number.
Show 3 more questions
What is the difference between pooled and single-donor products?
What is human complement used for in meningococcal and gonococcal vaccine research?
Can I use human complement for complement-dependent cytotoxicity (CDC) assays and disease models?
Publications citing this product (1)
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Serum bactericidal assay for the evaluation of typhoid vaccine using a semi-automated colony-counting method
Where the paper cites Pel-Freez
…4-nitrophenyl phosphate disodium hexahydrate were purchased from Sigma-Aldrich (St. Louis, MO). Baby rabbit (3- to 4-week-old) and adult rabbit (8- to 12-week-old) complements were purchased from Pel-Freez Biologicals (Rogers, AR). Guinea pig and human complements were purchased from Rockland (Gilbertsville, PA) and Valley Biomedical (Winchester, VA), respectively. All complements were stored in aliquots at −80…
Product References
- Salic acid protects nontypeable Haemophilus influenza from natural IgM and promotes survival in murine respiratory tract.
Jackson, M. D., Wong, S. M. & Akerley, B. J. Sialic acid protects nontypeable haemophilus influenzae from natural igm and promotes survival in murine respiratory tract. Infect. Immun. 89, (2021).
- Development of Complement Factor H–Based Immunotherapeutic Molecules in Tobacco Plants Against Multidrug-Resistant Neisseria gonorrhoeae
Shaughnessy, J. et al. Development of Complement Factor H–Based Immunotherapeutic Molecules in Tobacco Plants Against Multidrug-Resistant Neisseria gonorrhoeae. Front. Immunol. 11, 2680 (2020).
- Synthetic DNA Delivery of an Optimized and Engineered Monoclonal Antibody Provides Rapid and Prolonged Protection against Experimental Gonococcal Infection
Parzych, E. M. et al. Synthetic dna delivery of an optimized and engineered monoclonal antibody provides rapid and prolonged protection against experimental gonococcal infection. MBio 12, 1–13 (2021).
- Neisseria meningitidis urethritis outbreak isolates express a novel factor H binding protein variant that is a potential target of group B-directed meningococcal (MenB) …
Tzeng, Y. L. et al. Neisseria meningitidis urethritis outbreak isolates express a novel factor H binding protein variant that is a potential target of group B-Directed meningococcal (menb) vaccines. Infect. Immun. 88, (2020).
- Vaccination with Detoxified Leukocidin AB Reduces Bacterial Load in a Staphylococcus aureus Minipig Deep Surgical Wound Infection Model
Fernandez, J. et al. Vaccination with Detoxified Leukocidin AB Reduces Bacterial Load in a Staphylococcus aureus Minipig Deep Surgical Wound Infection Model . J. Infect. Dis. (2021).
- Preclinical efficacy of a lipooligosaccharide peptide mimic candidate gonococcal vaccine
Gulati, S. et al. Preclinical efficacy of a lipooligosaccharide peptide mimic candidate Gonococcal vaccine. MBio 10, (2019).
- Complement-Dependent Serum Bactericidal Assays for Neisseria gonorrhoeae
Gulati, S., Rice, P. A. & Ram, S. Complement-Dependent Serum Bactericidal Assays for Neisseria gonorrhoeae. in Methods in Molecular Biology vol. 1997 267–280 (Humana Press Inc., 2019).
- Development of Complement Factor H–Based Immunotherapeutic Molecules in Tobacco Plants Against Multidrug-Resistant Neisseria
Shaughnessy, J. et al. Development of Complement Factor H–Based Immunotherapeutic Molecules in Tobacco Plants Against Multidrug-Resistant Neisseria gonorrhoeae. Front. Immunol. 11, (2020).
Alternate Names
Pooled Human Complement Serum