Description
Native pentameric human C-reactive protein (CRP / pCRP) purified from ascitic fluid of donors screened negative for HBsAg, HCV, HIV-1 and HIV-2 antibodies. Sequential chromatography on CH-Sepharose (calcium-dependent affinity) and hydroxylapatite delivers a 26 kDa single band on reduced SDS-PAGE with =98 % purity, while preserving the calcium-dependent pentameric quaternary structure essential for native CRP function. The product is supplied as a 10 mg/mL solution in calcium-stabilised buffer (100 mM NaCl, 10 mM Tris, 2 mM CaCl2, 0.1 % sodium azide), so it can be used directly without further reconstitution.
Because the CRP pentamer is intact and free of stabilising additives that interfere with downstream chemistry, cat. 226 is the recommended starting material for the **Potempa method** of generating monomeric CRP (mCRP) — urea/EDTA chelation followed by dialysis — which yields the bioactive monomer used in neuroinflammation, microglial-activation, endothelial-rafts and chondrocyte-activation studies (see Cited use cases below). The same lot serves equally well as a high-purity immunogen, an ELISA microplate-coating antigen, or a ligand for affinity-chromatography columns.
Specifications
Catalog number: 226
Amount: 1 mg
Source: Human ascitic fluid (HBsAg / HCV / HIV-1 / HIV-2 antibody-negative)
Purity: =98 % on reduced SDS-PAGE; single band at 26 kDa
Format: Sterile-filtered protein solution, 10 mg/mL, in 100 mM NaCl, 10 mM Tris, 2 mM CaCl2, 0.1 % NaN3
Purification: CH-Sepharose calcium-dependent affinity chromatography, followed by hydroxylapatite chromatography
Quaternary form: Native pentamer (calcium-dependent assembly preserved by the 2 mM CaCl2 formulation)
Storage
Shipping at ambient temperature.
Long-term storage: 1 year at +4 °C.
DO NOT FREEZE — freezing disrupts the calcium-dependent pentameric assembly.
Applications
- Pure immunogen for raising polyclonal and monoclonal anti-CRP antibodies.
- ELISA / immunoassay coating antigen for plate-based CRP detection and antibody-titre assays.
- Affinity-chromatography ligand for capture of anti-CRP antibodies, CRP-binding proteins and complement component C1q.
- Starting material for monomeric CRP (mCRP) preparation by the Potempa urea/EDTA chelation method — the established protocol for generating mCRP as a pro-inflammatory agonist in neuroinflammation, microglial-activation, endothelial and chondrocyte cell models.
- Standard / calibrator for in-house CRP assay development.
- Substrate for studies of CRP–ligand interactions (phosphocholine, C1q, lipoproteins, Fc? receptors).
Citations
The neuroinflammation group of Coral Sanfeliu and Cristina Suñol at IIBB-CSIC (Barcelona) has used cat. 226 across a multi-year programme on Alzheimer's-related microglial inflammation, in each case using the YO Proteins native pentameric CRP as the starting material for the Potempa mCRP-generation protocol (1:1 EDTA/urea chelation: 10 mM EDTA, 8 M urea, 37 °C 2 h; dialysis at 20 kDa MWCO in 25 mM Tris-HCl, 50 mM NaCl, pH 8.3, 24 h). The resulting monomeric CRP is the actual pro-inflammatory agonist used in their cell models.
(1) Bartra C. et al. (2024) — Resveratrol activates antioxidant protective mechanisms in cellular models of Alzheimer's disease inflammation. Antioxidants 13(2): 177. doi:10.3390/antiox13020177.
mCRP generated from cat. 226 was used to challenge BV2 microglia and primary mixed glial cultures (rat) at 25 and 50 µg/mL — concentrations calibrated against LPS at 100 ng/mL — and the protective effects of resveratrol on the SIRT1 / Nrf2 / NF-?B pathways were assessed. The study identifies resveratrol-driven antioxidant and anti-inflammatory mechanisms that counteract mCRP-induced neuroinflammation.
(2) Bartra C. et al. (2024/2025) — Microglial pro-inflammatory mechanisms induced by monomeric C-reactive protein are counteracted by soluble epoxide hydrolase inhibitors. International Immunopharmacology 155: 114644.
mCRP generated from cat. 226 (25 and 50 µg/mL) was used to characterise the pro-inflammatory phenotype of microglia, mapping iNOS, NLRP3 inflammasome, and COX-2 / PGE2 pathways and demonstrating M1-like polarisation. The newly synthesised soluble-epoxide-hydrolase inhibitors UB-SCG-55 and UB-SCG-65 were benchmarked against TPPU and shown to counteract the mCRP-induced phenotype. The paper also visualises mCRP binding to and crossing the BV2 cell membrane.
(3) Bartra i Cabré C. (2024) — PhD thesis: "The impact of soluble epoxide hydrolase inhibition and epoxyeicosatrienoic acids on early-life microglia activation and neuroinflammatory responses in the brain", University of Barcelona.
Consolidates the above work, with cat. 226 used throughout as the standard source of native CRP for mCRP generation in BV2 cells and primary rat microglial cultures. The thesis includes orthogonal-view confocal imaging of mCRP intracellular trafficking and lectin-staining-based microglial morphology phenotyping.
(4) Ghosh A. (Ed.) (2022) — Biomarkers in Neurodegenerative Diseases 2.0, MDPI / Biomedicines special issue reprint. ISBN 978-3-0365-3766-8.
Native CRP from YO Proteins (cat. 226) is used in the included Bartra-group contribution to generate mCRP by the Potempa method, in combination with the anti-mCRP monoclonal antibody clone 8C10 (Potempa hybridoma) which blocks mCRP-induced U937 monocyte activation. The chapter contributes to the broader case that mCRP is a clinically actionable neuroinflammation marker.
