Mouse/Rat Flt-3 Ligand/FLT3L Quantikine ELISA Kit Summary

Product Summary

The Quantikine Mouse/Rat Flt-3 Ligand Immunoassay is a 4.5 hour solid phase ELISA designed to measure mouse or rat Flt-3 Ligand levels in cell culture supernates and serum. It contains NS0-expressed recombinant mouse Flt-3 Ligand and antibodies raised against the recombinant protein. Results obtained for naturally occurring mouse or rat Flt-3 Ligand showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values of natural mouse/rat Flt-3 Ligand.

Preparation and Storage

Background: Flt-3 Ligand/FLT3L

Flt-3 Ligand, also known as FL, is an alpha-helical cytokine that promotes the differentiation of multiple hematopoietic cell lineages. Mature human Flt-3 Ligand consists of a 158 amino acid (aa) extracellular domain (ECD) with a cytokine-like domain and a juxtamembrane tether region, a 21 aa transmembrane segment, and a 30 aa cytoplasmic tail. Within the ECD, human Flt-3 Ligand shares 71% and 65% aa sequence identity with mouse and rat Flt-3 Ligand, respectively. Human and mouse Flt-3 Ligand show cross-species activity. Flt-3 Ligand is expressed as a noncovalently-linked dimer by T cells and bone marrow and thymic fibroblasts. Each 36 kDa chain carries approximately 12 kDa of N- and O-linked carbohydrates. Alternate splicing and proteolytic cleavage of the transmembrane form can generate a soluble 30 kDa fragment that includes the cytokine domain. Alternate splicing of human Flt-3 Ligand also generates membrane-associated isoforms that contain either a truncated cytoplasmic tail or an 85 aa substitution following the cytokine domain. Both transmembrane and soluble Flt-3 Ligand signal through the tyrosine kinase receptor Flt-3/Flk-2. Flt-3 Ligand induces the expansion of monocytes and immature dendritic cells as well as early B cell lineage differentiation. It synergizes with IL-3, GM-CSF, and SCF to promote the mobilization and myeloid differentiation of hematopoietic stem cells. It cooperates with IL-2, -6, -7, and -15 to induce NK cell development and with IL-3, -7, and -11 to induce terminal B cell maturation. Animal studies also show Flt-3 Ligand to reduce the severity of experimentally induced allergic inflammation.

Assay Procedure

Refer to the product datasheet for the complete assay procedure.

Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.

1.    Prepare all reagents, standard dilutions, and samples as directed in the product insert.

2.    Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.

3.    Add 50 μL of Assay Diluent to each well.

4.    Add 50 μL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours.

5.    Aspirate each well and wash, repeating the process 4 times for a total of 5 washes.

6.    Add 100 μL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 2 hours.

7.    Aspirate and wash 5 times.

8.    Add 100 μL Substrate Solution to each well.

9.    Add 100 μL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.