Human CXCL9 Serum OneStep ELISA Kit

Catalog Number: S0C3218 Reactivity: Hu Conjugation: Brand: Starter

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$700 USD

Size: 1x96T 1x24T 5x96T 10x96T

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Product Details

Product Specification

Antigen	CXCL9
Immunogen	Recombinant Protein
Antibody Type	Recombinant mAb
Reactivity	Hu
Purification	Protein A
Stability & Storage	12 months from date of receipt / reconstitution, 2 to 8°C as supplied.

Kit

Precision	Intra-assay: 2.6% Inter-assay: 4.9%
Sample type	Serum
Assay type	Sandwich (quantitative)
Sensitivity	3.54 pg/mL
Range	23.4 pg/mL – 1500 pg/mL
Recovery	Serum: 94%
Assay time	60 minutes
Species reactivity	Hu

Background

Human CXCL9, also known as Monokine Induced by Interferon-Gamma (MIG), is a small cytokine belonging to the CXC chemokine family that plays a critical role in immune responses. It is primarily secreted by monocytes, macrophages, and endothelial cells in response to stimulation by interferon-gamma (IFN-γ), with its expression further enhanced by TNF. As an ELR-negative chemokine, CXCL9 selectively attracts activated T lymphocytes and Th1 cells by binding to its receptor, CXCR3, without affecting neutrophils. The protein functions as a potent inhibitor of angiogenesis and contributes to anti-tumor immunity by promoting the infiltration of effector T cells into the tumor microenvironment. The mature, secreted human CXCL9 protein consists of 103 amino acids and has a molecular weight of approximately 11.7 kDa. It is synthesized as a 125-amino-acid precursor with a 22-residue signal peptide that is cleaved to yield the active form. Due to its central role in Th1-mediated inflammation and its involvement in conditions ranging from autoimmune diseases to cancer, CXCL9 is an important research target and a potential biomarker for various pathological states.

Picture

ELISA

Standard Curve
Example of Human CXCL9 standard curve in Assay Diluent HA4. Plotted are the background-subtracted data.
This standard curve is provided for demonstration only.

Spike Recovery
The recovery of Human CXCL9 was evaluated in activated samples spiked with concentrations spanning the entire assay range.

Dilution Linearity
The concentrations of Human CXCL9 were measured and interpolated from the target standard curves and corrected for sample dilution.
The leftmost bar in the graph shows biological samples diluted in Assay Diluent to 25% concentration. "undiluted" was defined as 25% biological sample. The subsequent bars represent two-fold serial dilutions of this reference. The mean target concentration was determined to be 304.4 pg/mL in Human serum.

Determination of Minimum Detectable Dose (MDD)
The MDD was determined using three independent lots of assay components. For each lot, 19 replicate measurements of the diluent (zero calibrator) were performed. The mean (AVERAGE) and standard deviation (STDEV) of the 19 replicates were calculated. The MDD for each lot was then calculated according to the following formula:
MDD = 2 × STDEV + AVERAGE

Intra-Assay Precision (Precision within an assay)
Three samples of known concentration were tested fifteen times on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays)
Three samples of known concentration were tested in separate assays to assess inter-assay precision. Assays were performed with at least three lots of components.

HOOK Effect Threshold
The upper limit of the HOOK effect was established at 100× the highest calibrator concentration (equivalent to a 2-log10 increase). No HOOK effect was observed below this threshold, confirming that samples within this concentration range yield reliable quantitative results without signal depression.

Cross-reactivity
The cross-reactivity between Mouse CXCL9 and Human CXCL9 was assessed by testing both proteins in the same assay system. Serial dilutions of each protein were measured, and the dose-response curves were compared. No significant cross-reactivity was observed when Mouse CXCL9 was tested in the Human CXCL9 assay, as the signals remained within the background range of the assay.

Serum levels in healthy individuals
Duplicate measurements were performed on serum samples obtained from ten individual healthy donors. Data are reported as dilution factor-corrected interpolated. The resultant mean CXCL9 concentration was 120.52 pg/mL, with a distribution spanning 77.88 to 207.65 pg/mL across the donor cohort.

Cross-reactivity
The heatmap displays OD450 ratios for serum samples from multiple species. Color intensity is proportional to the O.D.450 ratio (test species / reference species). Darker colors indicate higher cross-reactivity.