ELISA Kit for the Quantitative Analysis of Human FSL1

 

 

The human FSL1 ELISA (enzyme-linked immunosorbent assay) kit is used for detection of human FSL1 in cell culture supernatants,human serum and plasma.THE ELISA KIT IS FOR RESEARCH USE ONLY. Please read this instruction manual carefully and check out the material provided before use, and you can contact with our company if any questions. You can enter our website or call us for other aim.

Introduction

Follistatinlike 1 (FSL1 or FSTL1) is a secreted 45~55 kDa extracellular glycoprotein，was initially discovered when previous investigators found that FSTL1 could be induced by transforming growth factor-b1. The human FSL1 cDNA encodes 308 amino acids (aa), including a 20 aa signal sequence. FSTL1 rich in cysteine (SPARC) that contain one follistatin-like domain and a pair of EF-hands. Mature human FSL1 shares 94%, 95%, 98% and 99% aa identity with mouse, rat, bovine and equine FSL1, respectively.

FSTL1 has been shown to reduce the growth of cancer cells, act as an Akt protein kinase-regulated cardioprotective factor in the heart, and serve as a target protein for autoantibodies in human rheumatoid arthritis. However, the receptor for FSTL1 in the body was not identified. Additionally, FSTL1 was found to be expressed in the nervous system and the neuronal function of FSTL1 was  served as a direct activator of Na+ ,K+ -ATPase (NKA).

Principles of the Test

The kit is a solid sandwich enzyme-linked immunosorbent assay for detection of human FSL1. An anti-human FSL1 monoclonal antibody has been absorbed onto the wells of the microtiter strips provided. Samples including specimens or standards were pipetted into wells. The human FSL1 in specimens or standards would be captured by the coated antibody and the free others were removed by washing. The human FSL1 biotin-conjugated antibody were added and binds to human FSL1 captured by the first antibody, which formed a sandwich. Streptavidin-HRP would be added and binds to the biotin conjugated antibody, then free Streptavidin-HRP would be removed during a wash step. After this, substrate solution would be added and catalyzed by the HRP, and a coloured product is formed. The intensity of the colored product is used to calculate in proportion to the amount of human FSL1 in the original specimen.  

Materials provided with the kit:

Specimen Collection

1.Collecting specimen as following:

A.The particulate of the cell culture supernatants should be removed before use.

B.Serum was obtained from clot at room temperature.

C.Please collect plasma with EDTA.

D.Assay immediately or store samples at －20℃. Avoid free-thaw cycles.

2. Antiseptic and anticoagulant should not appear in Serum samples.

3. Any particulate should be removed from samples before use.

4. Do not use grossly hemolyzed or lipemic samples.

Note: Strongly recommend that the serum and plasma samples should be diluent as doubling dilution before use.

Precautions for use:

1.Please storage the Kit at 2～8℃。

2. Washing buffer concentrate may have crystal in low temperature, and you can melt its in water-bath before use.

3. Please discard the remains after use of the dissolved standard.

4. Avoid contact of substrate solution with oxidizing agents and metal.

5. Usage of disposable pipette tips avoid microbial contamination or cross-contamination of reagents or specimens.

6. Do not mix or substitute reagents with those from other lots or other sources.

7. To ensure the adequate mixture of added reagents, please tap gently the plate after the wells were filled with liquid.

8. Incubation temperature should be 25～28℃.

9. Wash step was crucial for whole assay process.

10. Duplicate wells of the same sample were recommended in assay process

11. Avoid the foam while pour the liquid into wells.

12.For serum or plasma samples ,the biotin-conjugated antibody should be incubate for at least 90 minutes.

Reagent Preparation

1.The reagents should be warmed up to room temperature before use. The remanent reagents must reseal and put into refrigeratory again as soon as possible.

2.Dilute 1ml of wash buffer Concentrate into 19ml deionized or distilled water to work.

3. If you have a 5x standard diluent, please dilute it with double steaming water or deionized water.

4. Add deionized or distilled water to the bottle according to the volume of the label and wait 15 minutes for complete dissolution. Incubation temperature should be 25～28℃. And in turn add the half concentration diluent by standard diluent .

Wash step:

Automated microplate washer or operating by pipette: Each well should be pour into300ul wash buffer and soak 15 or 30 seconds,then be aspirated, five times process were repeated. After the last wash, remove remaining wash buffer by aspirating. Invert the plate and blot it against clean paper towels.

Materials Required But Not Provided

1. pipettes and pipette tips

2. Microwell strip reader capable of reading at 450 nm (540 nm as optional reference wave length)

3. automated microplate washer

4.Glass-distilled or deionized water

Assay procedure

1.The needed strips were putted into the frame, the remains were returned into foil pouch and resealed.

2.Blank well were recommended, which only color reagent and stop solution be added. It is suggested that each testing with gradient density of standard for standard curve.

3.Add 100ul of standard or sample.Cover with the Plate Covers provided.Incubate for 2 hours at room temperature If assay the serum sample,you should add 50μl assay buffer with 50μl sample into the wells,if the protein concentration is higher than the range of the Kit, add the same quantitys assay buffer with the sample, the deficiency should be complemented with sample diluent to 100μl per well.

4.Five times wash process were repeated.

5.Add 100ul of detection antibody. Cover with the Plate Covers provided.Incubate for 1 hour at room temperature.

6.Five times wash process were repeated.

7.Add 100ul of Streptavidin-HRP. Cover with the Plate Covers provided. Lucifugal incubation for 20 minutes at room temperature.

8.Five times wash process were repeated.

9.Add 100ul of TMB，Lucifugal incubation for 20 minutes at room temperature.

10.Add 50ul of stop solution to each well, determine the optical density of each well within 10 minutes.

Typical Data and Standard Curve

Human FSL1 Standard Curve

 

Sensitivity, Specificity, Repeatability

Sensitivity: repeated assays were evaluated and the minimum detectable dose was0. 31ng/ml.

Specificity : No significant cross-reactivity or interference with human Agrin,Follistatin (315),FSTL4,FSTL5,and have 11.7% cross-reactivity with mouse Follistatinlike 1 .

Repeatability: The coefficient of variation between wells or plates is less than 10 percent.