Rat Pulmonary Surfactant-associated protein D (SP-D) ELISA kit

Code CSB-E12632r
Size 96T,5×96T,10×96T How to order?
Trial Size 24T ELISA kits trial application
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Product Details


The rat SP-D ELISA Kit is used to quantitatively measure SP-D concentrations in rat serum, plasma, or tissue homogenates. It performs well in important characteristics, including sensitivity, specificity, precision, recovery, linearity, and lot-to-lot consistency. This assay is based on the sandwich ELISA mechanism and enzyme-substrate chromogenic reaction. The solution color develops proportionally to the amount of SP-D in the sample. And the intensity of the color can be measured at 450 nm via a microplate reader.

SP-D, encoded by the gene SFTPD, is a multimeric collectin that is primarily expressed in the lung and is involved in the modulation of pulmonary surfactants, maintenance of lipid homeostasis in the lung, and promotion of innate immunity to protect the lungs from microbial and chemical insults. SP-D mainly functions to aggregate and enhance phagocytosis of dying host cells and microbes such as bacteria, viruses, fungi, and helminthic parasites thus aiding their neutralization and clearance. Levels of SP-D are related to proinflammatory immune responses, mainly when alveolar macrophages interact with the trimeric form through their CD91 receptor, activating the p38 MAPK signaling pathway to elicit Th1 responses. SP-D production is affected by various lung diseases, and SP-D is regarded as a biomarker of lung inflammation.

Target Name surfactant protein D
Alternative Names Sftpd ELISA Kit; Sftp4 ELISA Kit; Pulmonary surfactant-associated protein D ELISA Kit; PSP-D ELISA Kit; SP-D ELISA Kit; CP4 ELISA Kit; Lung surfactant protein D ELISA Kit
Abbreviation SFTPD
Uniprot No. P35248
Species Rattus norvegicus (Rat)
Sample Types serum, plasma, tissue homogenates
Detection Range 0.312 ng/mL-20 ng/mL
Sensitivity 0.078 ng/mL
Assay Time 1-5h
Sample Volume 50-100ul
Detection Wavelength 450 nm
Research Area Signal Transduction
Assay Principle quantitative
Measurement Sandwich
Intra-assay Precision (Precision within an assay): CV%<8%      
Three samples of known concentration were tested twenty times on one plate to assess.  
Inter-assay Precision (Precision between assays): CV%<10%      
Three samples of known concentration were tested in twenty assays to assess.    
To assess the linearity of the assay, samples were spiked with high concentrations of rat SP-D in various matrices and diluted with the Sample Diluent to produce samples with values within the dynamic range of the assay.
  Sample Serum(n=4)  
1:5 Average % 88  
Range % 82-92  
1:10 Average % 94  
Range % 90-99  
1:20 Average % 95  
Range % 91-101  
1:40 Average % 94  
Range % 90-98  
The recovery of rat SP-D spiked to levels throughout the range of the assay in various matrices was evaluated. Samples were diluted prior to assay as directed in the Sample Preparation section.
Sample Type Average % Recovery Range  
Serum (n=5) 89 85-96  
EDTA plasma (n=4) 92 87-98  
Typical Data
These standard curves are provided for demonstration only. A standard curve should be generated for each set of samples assayed.
ng/ml OD1 OD2 Average Corrected  
20 2.689 2.697 2.693 2.508  
10 2.001 2.054 2.028 1.843  
5 1.555 1.579 1.567 1.382  
2.5 1.112 1.165 1.139 0.954  
1.25 0.687 0.697 0.692 0.507  
0.625 0.442 0.475 0.459 0.274  
0.312 0.382 0.396 0.389 0.204  
0 0.184 0.186 0.185    
ELISA Data Analysis Watch ELISA data processing video & download Curve Expert if needed
and FAQs
Storage Store at 2-8°C. Please refer to protocol.
Lead Time 3-5 working days

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Target Background

(From Uniprot)
Contributes to the lung's defense against inhaled microorganisms, organic antigens and toxins. Interacts with compounds such as bacterial lipopolysaccharides, oligosaccharides and fatty acids and modulates leukocyte action in immune response. May participate in the extracellular reorganization or turnover of pulmonary surfactant. Binds strongly maltose residues and to a lesser extent other alpha-glucosyl moieties.
Gene References into Functions
  1. in acute lung injury, serum level increased from day 5, peaked on day 10, and then gradually decreased until day 28 PMID: 27541374
  2. SPA binds dipalmitoyl-phosphatidylcholine, the major surfactant lipid component, but not phosphatidylinositol; SPD exhibits the opposite preference. Data suggest flexibility in a key surface loop supports distinctive lipid binding of SPA; quadruple mutant SPA (E171D/P175E/R197N/K203D) that introduces SPD-like loop-stabilizing Ca2+ binding site in carbohydrate recognition domain exhibits ligand-binding preferences of SPD. PMID: 28719181
  3. In rat SP-D overexpressed mice, the lipopolysaccharide-induced levels of TNF-alpha and IL-10 in amniotic fluid and fetal serum and the expression of IL-10 in placenta and fetal membranes were significantly different from wild-type mice. PMID: 22892325
  4. Surfactant protein D modulated subpollen particle uptake in a cell type specific way (e.g. greater number of macrophages and epithelial cells, which participated in allergen particle uptake) and led to a decreased secretion of pro-inflammatory cytokines. PMID: 22296755
  5. Silica exposure causes dynamic changes of SP-D and CC16 protein expression in lung tissue and bronchoalveolar lavage fluid. PMID: 19080379
  6. An extended binding site for influenza A virus; calcium-dependent antiviral activity involves residues flanking the primary carbohydrate binding site as well as more remote residues displayed on the carbohydrate recognition domain surface. PMID: 20601494
  7. SP-D promotes attachment of allergen-containing subpollen particles to epithelial cells and may thus be involved in the inflammatory response to inhaled allergen. PMID: 20569420
  8. analysis of myeloperoxidase-dependent inactivation of surfactant protein D in vitro and in vivo PMID: 20228064
  9. Results suggest that SP-D-dependent processes regulating surfactant lipid homeostasis were disassociated from those mediating emphysema. PMID: 12163500
  10. Heterogeneous allele expression of SP-D mRNA in large intestine and other tissues. PMID: 12464693
  11. SP-A and SP-D are antimicrobial proteins that directly inhibit the proliferation of Gram-negative bacteria in a macrophage- and aggregation-independent manner by increasing the permeability of the microbial cell membrane PMID: 12750409
  12. SP-A and SP-D are antimicrobial proteins that directly inhibit the growth of Histoplasma capsulatum by increasing permeability of the organism PMID: 12857753
  13. SP-D interacts with chlamydial pathogens and enhance their phagocytosis into macrophages PMID: 15075250
  14. Degradation of pulmonary surfactant protein D by Pseudomonas aeruginosa elastase abrogates innate immune function PMID: 15123664
  15. SP-A and SP-D enhance mannose receptor-mediated phagocytosis of M. avium by macrophages PMID: 15187139
  16. results indicated SP-A & SP-D have distinct functions in lung homeostasis & the function of the neck domain & carbohydrate recognition domain of SP-D is dependent on its own NH2-terminal & collagenous domains that cannot be complemented by those of SP-A PMID: 16500946
  17. The ligand binding of homologous human, rat, and mouse trimeric trimeric neck plus carbohydrate recognition domain (neck+CRD) fusion proteins, each with identical N-terminal tags remote from the ligand-binding surface, was compared. PMID: 16514117
  18. VEGF increased expression of SP-D mRNA in preterm rat lung. PMID: 17267143
  19. Interactions with the side chain of inner core heptoses provide a potential mechanism for the recognition of diverse types of lipopolysaccharides by SP-D. PMID: 18092821
  20. These results show that antiviral activities of surfactant protein-D can be reproduced without the N-terminal and collagen domains and that cross-linking of these domains is essential for anti-influenza A virus activity. PMID: 18302538
  21. After OVA challenge alveolar epithelial cells Type II (AEII) show a significantly higher expression of SP-A and SP-D leading also to higher amounts of both SPs in BALF, and macrophages gather predominantly SP-A. PMID: 18802356
  22. S-nitrosylation of SP-D causes quaternary structural alterations and a swtich to its inflammatory signaling role. PMID: 19007302
  23. Multimerization of surfactant protein D, but not its collagen domain, is required for antiviral and opsonic activities related to influenza virus. PMID: 19017984

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Subcellular Location Secreted, extracellular space, extracellular matrix. Secreted, extracellular space, surface film.
Protein Families SFTPD family
Database Links

KEGG: rno:25350

UniGene: Rn.11348

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