DESCRIPTION

CD40 is a member of the tumor necrosis factor receptor superfamily. It is expressed in various immune cells, including B cells, macrophages, and dendritic cells. CD40 functions as a co-stimulatory receptor that interacts with its ligand, CD40L (CD154), primarily expressed on activated CD4+ T cells. This interaction is essential for T-cell activation, immunoglobulin class switching, memory B cell development, and germinal center formation. CD40 signaling is mediated by recruitment of TRAFs (TNF receptorassociated factors) and NF-κB activation, supplemented by pathways such as PI3K/AKT, MAPKs, and JAK3/STATs. Additionally, circulating soluble CD40 levels are elevated in patients with chronic renal failure, chronic liver diseases, Alzheimer's disease, systemic sclerosis, and hematological malignancies.

PRINCIPLE OF THE ASSAY

Sandwich ELISA structure (Detection antibody labeled with HRP) A capture antibody is pre-coated onto the bottom of wells which binds to analyte of interest. A detection antibody labeled with HRP also binds to the analyte. TMB acts as the HRP substrate and the solution color will change from colorless to blue. A stop solution containing sulfuric acid turns solution yellow. The color intensity is proportional to the quantity of bound protein which is measurable at 450 nm with the correction wavelength set at 630 nm.

PRECISION

Intra-assay Precision (Precision within an assay) Three samples of known concentration were tested 8 times on one plate to assess intra-assay precision. Inter-assay Precision (Precision between assays) Three samples of known concentration were tested in 16 separate assays to assess inter-assay precision.

Intra-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	8	2,443.7	155.0	6.3
2	8	716.7	8.3	1.2
3	8	241.9	9.4	3.9

Inter-assay Precision

Sample	n	Mean (pg/mL)	SD	CV%
1	16	2,463.1	144.9	5.9
2	16	702.8	22.8	3.2
3	16	242.1	8.9	3.7

RECOVERY

The recovery of human CD40 spiked to three different levels throughout the range of the assay in various matrices was evaluated.

Sample Type		Average% of Expected	Range (%)
Human serum	1:8	98	97-100
	1:16	97	96-97
Cell culture supernatant	1:2	92	91-94
Saliva	1:8	89	87-91
Human milk	1:4	92	90-94
	1:8	101	99-103

LINEARITY

To assess the linearity of the assay, samples were diluted with the appropriate Sample Diluent to produce samples with values within the dynamic range of the assay.

		Human serum(Sample Diluent PT1)	Cell culturesupernatant(Sample Diluent PT4B1)	Saliva(Sample Diluent PT1)	Human milk(Sample Diluent PT3)
1:2	Average% of Expected	100	100	100	100
	Range (%)	-	-	-	-
1:4	Average% of Expected	116	113	93	115
	Range (%)	110-122	108-120	87-99	112-118
1:8	Average% of Expected	122	115	96	125
	Range (%)	106-130	108-123	78-114	122-127
1:16	Average% of Expected	121	117	99	124
	Range (%)	108-130	116-119	77-121	120-128

CALIBRATION

This immunoassay is calibrated against a highly purified recombinant human CD40 produced at Sunlong Medical™.

Ordering & shipping

• Minimum order: 1 kit
• Lead time: varies with order quantity and specifications. Please consult your local distributor or our sales team for confirmation
• Payment: T/T 100% in advance; PayPal; Alibaba Trade Assurance
• Shipping: FedEx / DHL / UPS express; cold-chain packing available on request
• Price: USD, per kit (48T / 96T options available)