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SP-D ELISA Kit [Human], 2 x 96 det. (CAT#: CB-P092-K) Datasheet

Product Type
Surfactant protein D (SP-D) belongs to the collectin family. These proteins are oligomeric proteins composed of carbohydrate recognition domains (CRD) attached to the collagen region. Although collectins use different CRD structures, they are similar in structure to fibrin, namely: the C-type lectin domain of collectins. The lung is the main site of SP-D synthesis, where molecules are produced by type II alveolar cells and unbranched bronchial epithelial cells and secreted to the epithelial surface. SP-D is also found in different epithelial cells of the gastrointestinal tract and various exocrine glands. SP-D is an important factor affecting the antimicrobial ability of the lungs. The antimicrobial defense mechanism of SP-D is direct conditioning, neutralization and agglutination. This results in limiting infection and at the same time coordinating the subsequent adaptive immune response. During inflammatory stress, the synthesis and secretion of SP-D increase significantly. In inflamed lungs, increased levels of SP-D in bronchial lavage fluid and tissues were found, especially in inflamed lungs, type II lung cells, Clara cells and proliferative goblet cells were found. The localization of SP-D in the lysosomal particles of endocytic vesicles and alveolar macrophages indicates receptor-mediated uptake. SP-D is also involved in the process of apoptosis. SP-D binds to apoptotic neutrophils and enhances its clearance rate through alveolar macrophages. Although no humans have described a complete lack of SP-D, the basic level is highly variable and largely determined by genetics. The SP-D levels of healthy individuals range from 200 ng/ml to 5200 ng/ml. The average level of SP-D has increased from 700 ng/ml for children to 1100 ng/ml for adults. The control level of bronchoalveolar fluid SP-D is 7 ng/ml to 28 μg/ml. During acute lung infections, SP-D levels will rise sharply, and in certain non-infectious lung diseases.
The human SP-D ELISA kit is used for the in vitro quantitative determination of human SP-D in plasma, bronchoalveolar lavage fluid and cell culture supernatant samples.
Human SP-D ELISA kit is a ready-to-use solid-phase enzyme-linked immunosorbent assay based on the sandwich principle. The working time is 3 hours. The effective format of two plates with twelve disposable 8-well strips allows free choice of batch size for determination. The samples and standards are incubated in microtiter wells coated with antibodies that recognize human SP-D. The biotinylated tracer antibody will bind to the captured human SP-D. The streptavidin-peroxidase conjugate will bind the biotinylated tracer antibody. The streptavidin-peroxidase conjugate will react with the substrate tetramethylbenzidine (TMB). The enzyme reaction is stopped by adding oxalic acid. Measure the absorbance at 450nm with a spectrophotometer. Draw a standard curve by plotting the absorbance (linear) relative to the corresponding concentration (logarithm) of the human SP-D standard. The concentration of human SP-D in a sample run at the same time as the standard can be determined from the standard curve.
2 x 96 det.
Detection Method
Enzyme immunoassay (ELISA) technique
Detection Limit
6.3 to 400 ng/ml
6.3 ng/ml
Serum, plasma, tissue homogenates, cell lysates, cell culture supernates and other biological fluids
Specimen Collection
Blood samples were collected using sterile venipuncture techniques, and serum was obtained using standard procedures. At least 5 ml of whole blood is recommended. Let the blood clot in the serum test tube for 60-65 minutes at room temperature (20-25°C). Centrifuge the blood sample and transfer the cell-free serum to a clean test tube. The serum must be handled correctly to prevent complement activation in vitro. Serum should be frozen in a sealed tube at -70°C or lower for long-term storage or transport on dry ice. The sample should not be frozen and thawed more than once. Do not use jaundice, lipemia and hemolytic serum. You cannot use heat-inactivated serum. Plasma cannot be used.
Sample Volume
100 µl/well
Species Reactivity
Cross Reactivity
Rat - Weak
Protocol Length
2 hours
Product should be stored at 4 °C. Under recommended storage conditions, product is stable for at least six months.
Research Use
For research use only. Not for use in or on humans or animals or for diagnostics. It is the responsibility of the user to comply with all local/state and Federal rules in the use of this product. Hycult Biotech is not responsible for any patent infringements that might result with the use of or derivation of this product.

All products and services are for Research Use Only. Do Not use in humans.


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