Individual Components Activity Test

Creative Biolabs is a cutting-edge complement testing service supplier with state-of-the-art facilities. Our dedicated scientists and technical experts have abundant experience in complement activity testing, which enables us to provide our clients with quality and professional individual components activity test services.

Overview of Individual Components Activity Test

Individual complement components can be quantitatively tested by immunoprecipitation assays, such as immunoprecipitation tests (radial immunodiffusion or nephelometer techniques), ELISA, and the like, without regard to functional activity. In routine testing, C3, C4, and B factors are most frequently measured, followed by C1 inhibitors and other components, to determine the diagnosis of complement-associated diseases. In most cases, total hemolytic activity (CH50 and AH50) indicates complement deficiency, and quantitative tests can be performed as an alternative to functional assays for individual components. If a defect is verified by this test, further functional tests are not required. On the other hand, if the quantitative test does not reveal any defects, a functional test is required to verify the diagnosis. The simplest method of detecting the functional activity of individual complement components is to test the ability of the sample to reconstitute the hemolytic activity of serum which is deficient for the protein. To finally demonstrate the lack of only one single component, the purified functionally active component can be added to the serum to restore the hemolytic activity of the corresponding pathway.

1. Quantitative Tests for Individual Components

Quantitative tests of complement components are the second most common complement test after CH50 and AH50. Quantification of most individual complement components can be performed by immunochemical assays including nephelometry, turbidometry and RID, ELISA and other methods. These measurements utilize the formation of antibody-antigen immune complexes to determine protein concentration. When the antigens, such as C1 inhibitor, C1q, C3, C4, and C5, FB, and FH, are in equilibrium with the antibodies to the complement components, immune complexes are formed and can then be subsequently measured.

1. Nephelometry: nephelometry is quantified based on the light scatter from immune complexes. The intensity of light scatter produced by an immune complex is proportional to the number of complexes present in the sample. This test method is usually used for the quantification of C3, FB, and C4.
2. Turbidimetry: in contrast to nephelometry which relies on light scatter, turbidimetry allows quantitation of antigens based on changes in the transmission of light. The same equilibrium is formed between the complement antigen and the antibody to form an immune complex, which in turn alters the transmission of light through the specimen in a manner that depends on the concentration of the complement factor of interest.
3. RID: RID is a versatile method allowing for measurement of complement component concentration (particularly for C2) or complement function. RID uses an agarose gel containing either antiserum to complement factor for component levels or heterologous red blood cells from sheep, rabbit, or chicken for functional assays. If it is an antiserum-type RID, a precipitin ring will be observed. If it is an erythrocyte agarose gel, hemolysis will be observed around the well. In both cases, the diameter around the well is proportional to either the antigen concentration or the complement activity.
4. ELISA and other tests: other complement components, such as C1 inhibitor, MASP-1/2, and regulators, are tested by ELISA or time-resolved immunofluorometric assay (TRIFMA).
2. Functional Activity Test for Individual Components

Normal concentrations of single components do not exclude functional defects. Thus, if a functional defect is suspected or needs to be ruled out, the functional activity of individual complement proteins needs to be tested. A simple way to detect the functional activity of individual complement components is to test for the sample's capability to reconstitute the total complement activity of a serum deficient for a known component. This can be done by using serum that depletes the actual component and adding fresh serum from the patient to see whether the activity can be restored.

Our Services of Individual Components Activity Test

Creative Biolabs has a robust standardized complement test platform and a variety of test technologies, such as nephelometry, ELISA, RID, and TRIFMA assays, to deliver fast, reliable & objective, easy to interpret results within 3 hours. We provide our customers with routine quantitative tests and functional activity test for individual components as well as a full range of complement components testing services, including but not limited to:

Creative Biolabs works closely with each customer, from researchers to diagnosticians, to provide their results in the most cost-effective and rapid way while maintaining customers’ confidentiality. If you have any questions, please do not hesitate to contact us.

Protocols

Hot Complement Serum Products

Published Data

Fig.1 ELISA assay of C3(H₂O).¹

The identification of a C3(H₂O) uptake mechanism has sparked renewed interest in this variant of the alternative pathway activator in human biospecimens. Until recently, no quantitative method existed to measure C3(H₂O) without interference from other complement activation products. Researchers have now developed an ELISA assay to quantify C3(H₂O), positioning it as a potential diagnostic and prognostic biomarker for human diseases. Initial applications of this assay allowed for the establishment of baseline C3(H₂O) levels in fluids from healthy individuals, as well as the optimization of sample storage and handling protocols. They observed approximately 500 ng/ml of C3(H₂O) in freshly collected serum and plasma—significantly lower than previous estimates derived from purified C3 samples.

Resources

Complement System Composition

Complement Activity/Function Assay Products

Reference

1. Elvington, Michelle, et al. "Development and optimization of an ELISA to quantitate C3 (H₂O) as a marker of human disease." Frontiers in immunology 10 (2019): 703. Distributed under Open Access license CC BY 4.0, without modification.

• Total Complement Activity Test
• Complement Activation Products Test
• Hemolytic Inhibition Assay
• Complement Inhibitor Validation
• Receptor Ligand Binding Assay
• Cell-based Complement Activity Assay
• Complement C1q-Binding Assays
• Complement C2 Functional Test
• Complement C3 Functional Test
• Complement C5 Functional Test
• Complement Factor B Functional Test
• Complement Factor D Functional Test
• Complement Factor H Functional Test
• Complement Factor I Functional Assay
• Complement Factor P Functional Test