Human Complement, Pooled, Lyophilized
Human serum collected to preserve complement activity, 0.2 µm filtered, aliquoted, frozen, and lyophilized.
Specifications
Physical State:
Lyophilized Powder
Storage:
-20°C or below
Release criteria
Complement activity (CH50):
> 100
Moisture:
< 5%
Lead time on this item is currently: 2-4 Weeks
Need help? Ask a Specialist Contact UsOR +1 (800) 643-3426
Product Overview
| Species: | Human |
|---|---|
| Product Types: | Complement |
| Source: | OTC Serum (Complement Preserved) |
| Pooling: | Pooled |
| Donor Sex: | Mixed |
| Physical State: | Lyophilized Powder |
| 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 Moisture: <5% Serum tested negative for infectious disease per FDA guidelines. |
| Storage Conditions: | -20°C or below |
| Shipping Conditions: | Cool packs |
| Packaging: | Glass vial |
| Expiration: | 1 year from date of receipt when stored dry at -20°C or below; reconstitute just before use and freeze any remainder at -70°C or below. Product quality is guaranteed to meet Pel-Freez Biologicals' specifications for this period when stored as indicated. |
Product Applications
- Serum bactericidal assay
- Opsonophagocytic assay
- Hemolytic complement assay
- ELISA
- Assay diluent & negative matrix
- Assay controls & calibrators
- Vaccine development
- In vitro diagnostics
Frequently Asked Questions
How does freezing and thawing affect complement activity?
Multiple freeze-thaw cycles will result in reduced complement potency, so we offer a variety of pack sizes to satisfy applications ranging from small scale assay development experiments to large scale clinical studies. We recommend limiting the number of freeze-thaw cycles and sub-aliquot into single-use quantities whenever possible in order to extend the shelf life of all of our complement products.
Should I choose lyophilized or frozen liquid complement?
We offer baby rabbit and human complement in both forms. Frozen liquid complement is ready to use after thawing and is stored at -70°C or below. Lyophilized complement is stored at -20°C or below, is easier to ship, and is reconstituted with sterile water to the label volume, or to a smaller volume when you need higher potency.
What is complement activity (CH50 / hemolytic titer) and how is it tested?
The hemolytic titer measures how well complement lyses antibody-sensitized sheep red blood cells; CH50 is the dilution of serum that lyses 50% of the cells. It is the release test for every lot of our complement products, and our heat-inactivated human products are CH50 tested to confirm that complement activity is absent.
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?
The ideal concentration of complement used in SBAs and OPKAs will vary with the specific pathogen and assay conditions. Typical concentrations range from 10-25%.
Why am I seeing non-specific killing in my opsonophagocytic killing assay?
Endogenous complement activity can cause intrinsic, non-specific bacterial killing. We recommend preventing this by heat-inactivating all OPA/OPKA antisera at 56°C for 30 minutes, and always running controls of complement, HL60 cells and bacteria without antiserum to assess non-specific killing. If you are still seeing higher than expected non-specific killing, try the following:
• 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.
• 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 4 more questions
What is the difference between pooled and single-donor products?
Pooled products combine material from multiple donors, which averages out donor-to-donor variation and gives large, uniform lots. Single-donor products come from one donor: their properties trace to that donor and can differ more between lots. Studies that need a single, well-characterized source, such as one complement lot carried through a clinical trial, use single-donor material.
How do I reconstitute lyophilized human serum products?
Lyophilized human serum products may be reconstituted by bringing the vial to ambient temperature then resuspending in sterile water equal to the volume on the product label. For lyophilized complement products, resuspending in a volume less than the label volume will increase complement potency, useful in applications requiring increased complement activity.
What is human complement used for in meningococcal and gonococcal vaccine research?
Human complement is the required complement source for the hSBA, the serum bactericidal assay used to evaluate serogroup B meningococcal vaccines such as 4CMenB and MenB-fHbp and the pentavalent MenABCWY vaccines. Neisseria binds human factor H to evade human complement, an interaction rabbit complement does not reproduce. Publications citing our human complement also cover Neisseria gonorrhoeae bactericidal assays and vaccine candidates, native outer membrane vesicle vaccines, and factor H and NspA binding studies.
Can I use human complement for complement-dependent cytotoxicity (CDC) assays and disease models?
Yes. Published work uses our human complement as the effector source for CDC of gene-edited pig cells and red blood cells in xenotransplantation studies, for aquaporin-4 antibody mediated astrocyte injury in neuromyelitis optica (NMOSD) models, and for testing complement inhibitors such as eculizumab and C1 esterase inhibitor. Neat pooled complement (34008) gives typical human complement activity; a single-donor lot (34017) keeps one donor's complement across a long study.
Alternate Names
Pooled Human Complement Serum (Neat) Lyophilized
