soluble Semaphorin 4D ELISA
First fully validated available assay. Only 10 μl/well. Highly specific. Fully validated. Convenient protocol. Proprietary product.
Assay characteristics:
| Cat.No.: | BI-20405 |
| Method: | Sandwich ELISA, HRP/TMB, 12x8-well strips |
| Sample type: | Plasma (EDTA, hep, citrate) |
| Standard range: | 0-2,000 pmol/l (7 plasma based standards) |
| Standard points: | 0/62.5/125/250/500/1,000/2,000 pmol/l |
| Control: | 2 controls |
| Sample size: | 10 μl / well |
| Incubation time: | 3 h / 1 h / 30 min |
| Unit conversion: | 1 pg/ml = 0.00127 pmol/l (MW: 78.9 kDa) |
Sensitivity:
LOD: 12 pmol/l (0 pmol/l + 3 SD); LLOQ: 31 pmol/l
Precision:
Intra-assay (n=5) ≤ 8%, Inter-assay (n=11) ≤ 11%
Spike/Recovery:
The mean recovery of recombinant SEMA4D (1,000 pM) in EDTA plasma is 92%.
The mean recovery of recombinant SEMA4D (1,000 pM) in heparin plasma is 103%.
The mean recovery of recombinant SEMA4D (1,000 pM) in citrate plasma is 83%.
Dilution linearity:
The dilution linearity (1+3) of endogenous sSEMA4D in EDTA plasma samples (n=4) is between 83-106%.
The dilution linearity (1+3) of recombinant sSEMA4D in EDTA plasma samples (n=6) is between 83-124%.
Values from apparently healthy individuals:
Median (EDTA plasma, n=44): 245 pmol/l.
It is recommended to establish the normal range for each laboratory.
ADDITIONAL INFORMATION
Human Semaphorin 4D (SEMA4D), also known as CD100, is a type I integral membrane glycoprotein with a molecular weight of 150 kDa. It consists of an extracellular region, a cysteine-rich PSI domain, and an Ig-like C2 type- domain, followed by a transmembrane region, and a cytoplasmatic tail. SEMA4D forms homodimers due to disulfide linkage, which is essential for successful interaction with its low affinity receptor CD72 primarily found in lymphoid tissues (1) and its high affinity receptors plexin-B1 and plexin-B2 (2, 3). Shedding near the cell membrane releases the extracellular region as 120 kDa bioactive soluble SEMA4D (sSEMA4D). Shedding can thereby happen spontaneously (4), or it can be the result of proteolytic cleavage by matrix metalloproteases (MMPs) like the Zn-dependent protease ADAM17 (5, 6).
LITERATURE
1. Semaphorins command cells to move. Kruger RP et al., Nature Rev Mol Cell Biol, 2005; 6:789-800.
2. The semaphorins. Yazdani U and Terman JR, Genome Biol, 2006; 7(3): 211.
3. Biology and function of neuroimmune semaphorins 4A and 4D. Nkyimbeng-Takwi EH and Chapoval SP, Immunol Res, 2011; 50 (1):10-21.
4. Structural basis of semaphorin-plexin signalling B.J.C. Janssen BJC et al., Nature, 2010; 467:1118-1122.
5. Semaphorins and their receptors in immune cell interactions. Suzuki K et al., Nature Immunology, 2007;9:17-23.
6. Sema4D induces angiogenesis through Met recruitment by Plexin B1. Conrotto P et al., Blood, 2005; 105:4321-4329.
7. Diverse roles for semaphorin-plexin signaling in the immune system. Takamatsu H et al., Trends Immunol, 2012; 33(3):127-135.
8. Bone cell communication factors and Semaphorins. Negishi-Koga T and Takayanagi H, Bonekey Rep, 2012; 1:183.
9. Suppression of bone formation by osteoclastic expression of semaphorin 4D. Negishi-Koga T et al., Nat Med, 2011; 17(11):1473-1480.
10. Soluble SEMA4D/CD100: A novel immunoregulator in infectious and inflammatory diseases. Maleki KT et al., Clinical Immunology, 2016; 163:52-59.
11. Anabolic bone formation via a site specific bone targeting delivery system by interfering with semaphorin 4D expression. Zhang Y et al., J Bone Miner Res, 2015; 30(2): 286-296.
12. Generation and preclinical characterization of an antibody specific for SEMA4D. Fisher TL et al., Mabs, 2016; 8(1):150-162.
13. Coagulation-induced elevated sSEMA4D concentrations in human serum versus plasma measured by sandwich ELISA. Laber et al., 2018; submitted.
Measurement of human soluble Semaphorin 4D in dialysis patients by ELISA
ISN Frontiers poster #P-195, Tokyo February 2018