C-reactive protein (CRP) is produced by the liver and is one of the so-called acute phase proteins. Its concentration in blood increases rapidly and considerably as a response to inflammation or infection. CRP is routinely used as a non-specific marker of inflammation. The level of CRP in the blood of healthy people is usually less than 10 mg/L. In infections caused by bacteria the concentration of CRP can quite easily increase tenfold. In contrast, infections of viral origin usually result in just a moderate increase in the level of CRP.

CRP binds to damaged cell membranes, apoptotic cells and bacteria. It has a high affinity towards phosphocholine but has also been shown to bind to other ligands. While the CRP-ligand complex can activate the classical complement pathway, the precise function of CRP in vivo is still not yet completely clear.

We offer over ten different monoclonal antibodies specific to human CRP. The majority of these mAbs are unaffected by the presence or absence of Ca²⁺ in the quantitative detection of CRP. However, some antibodies and antibody pairs depend on Ca²⁺ and the binding of CRP may be abolished in the presence of EDTA. This should be kept in mind when designing a CRP immunoassay. We also provide purified native CRP and CRP-free serum.

Effect of EDTA on CRP measurements. In this sandwich immunoassay, pair C3-C6 (left) shows a dependence on Ca²⁺ as it fails to recognize CRP in the presence of EDTA. In contrast, pair C5-CRP135 is unaffected by EDTA in the solution.

High-sensitivity CRP (hsCRP)

It should be noted that CRP is also used as a marker of increased risk for cardiac diseases. In this, it is the basal level of CRP that has more clinical significance and therefore, the assays need to be highly sensitive and aimed at nanogram per milliliter CRP level distinction. Our anti-CRP antibodies are suitable for the development of a quantitative hsCRP assay. For more information, please see the hsCRP TechNotes.

Products:

Cat#                   Product name
4C28                  C-reactive protein, in vivo, antibody
4C28cc              C-reactive protein, in vitro, antibody
8C72                 C-reactive protein (CRP), human, antigen
8CFS                 CRP free serum

Literature:

Inflammation Brochure
Cardiac Markers Brochure
hsCRP TechNotes