| Field | Specification |
|---|---|
| Mfr No | |
| Alternative Names | C4b |
| Assay Time | |
| Assay Type | |
| Detection Method | |
| Product Type | |
| Reactivity | |
| Sample Type(s) | Cell culture supernatants, Serum, Plasma, Other biological fluids |
| Shipping | |
| Storage |
Features & Benefits
Human Complement fragment 4b (C4b) ELISA Kit has high sensitivity and excellent specificity for detection of Human C4b. No significant cross-reactivity or interference between Human C4b and analogues was observed.
Background
The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen's plasma membrane. It is part of the innate immune system, which is not adaptable and does not change over the course of an individual's lifetime. It can be recruited and brought into action by the adaptive immune system. The complement system consists of a number of small proteins found in the blood, in general synthesized by the liver, and normally circulating as inactive precursors (pro-proteins). When stimulated by one of several triggers, proteases in the system cleave specific proteins to release cytokines and initiate an amplifying cascade of further cleavages. The end result of this complement activation or complement fixation cascade is stimulation of phagocytes to clear foreign and damaged material, proxy inflammation to attract additional phagocytes, and activation of the cell-killing membrane attack complex. Over 30 proteins and protein fragments make up the complement system, including serum proteins, serosal proteins, and cell membrane receptors. They account for about 10% of the globulin fraction of blood serum and can serve as opsonins. Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway, and the lectin pathway.
This Complement fragment 4b (C4b) ELISA kit is validated for use with Cell culture supernatants, Serum, Plasma, Other biological fluids. Samples should be collected, processed, and stored correctly to preserve analyte integrity — avoid repeated freeze-thaw cycles and centrifuge to remove particulates before use. Dilute samples exceeding the kit's detection range using the supplied assay diluent. Hemolytic, icteric, or lipemic samples may affect assay performance and should be tested with caution.
This is a sandwich ELISA kit employing an HRP (horseradish peroxidase)-conjugated secondary antibody paired with a TMB (3,3′,5,5′-tetramethylbenzidine) colorimetric substrate. In the sandwich format, the target analyte Complement fragment 4b (C4b) captured on the microplate surface is detected by the conjugated antibody, generating a colorimetric signal proportional to analyte concentration. The reaction is stopped and absorbance measured at 450 nm on a standard microplate reader.
The complete protocol, from sample addition to final plate reading, requires approximately 3–5 hours. This includes two incubation periods (analyte binding and detection antibody steps), intermediate wash cycles to remove unbound material, 15–30 minutes of TMB substrate development, and final stop-solution addition before absorbance reading. Exact timing will vary with experience level and the number of samples processed in parallel.
Required equipment: (1) a microplate spectrophotometer capable of reading absorbance at 450 nm (reference wavelength 540–570 nm recommended for background correction); (2) precision single-channel or multichannel pipettes; (3) a plate washer or multichannel aspirator; (4) a microcentrifuge for sample clarification; and (5) a 37°C incubator or stable room-temperature environment. No fluorescence or luminescence reader is required — standard colorimetric plate readers are fully compatible with this kit.
This ELISA kit is formally validated for Human. Cross-reactivity with species not listed in the specification has not been independently characterized. Variability in protein sequence homology across species means that performance in unlisted species cannot be guaranteed without additional validation. For cross-species detection requirements or non-standard sample matrices, please contact BioHippo support or refer to the manufacturer's technical team for guidance.
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