Human RANKL(total) soluble ELISA kit

Sample

serum, plasma

Species Reactivity

Human

Detection Method

sandwich

Intended Use

The described Enzyme-Linked-Immuno-Sorbent-Assay (ELISA) is intended for the quantitative determination of total sRANKL (human) in serum and plasma. It is for in vitro diagnostic use only.
The assay detects free as well as OPG-bound sRANKL in serum and cell culture supernatants. Free sRANKL can be mathematically estimated when the assay is performed once with an excess of OPG (free and OPG-bound sRANKL are determined), and then without any addition of OPG (only OPG-sRANKL-complexes already present in the sample are determined).

Storage

Store the kit at 4°C upon receipt. For more detailed information, please download the following document on our website.

Performance Characteristics

##Precision and reproducibility##
Intra-Assay Precision (n=20): 0.9%-3.5%
Inter-Assay Precision (n=20): 7.1%-9.3%
##Recovery ##
2 samples were spiked with 3 different total sRANKL standards and measured using this assay.

##Sensitivity##
The sensitivity was set as B0 + 2SD. The zero-standard was measured 20 times.

##Linearity##
Two patient samples were diluted with sample dilution buffer and analyzed. The results are shown below:

n= 2

General Description

RANKL (receptor activator of nuclear factor (NF)-kB ligand; also: osteoprotegerin ligand, OPGL), its cellular receptor, receptor activator of NF-kB (RANK), and the decoy receptor, osteoprotegerin (OPG) have been identified as the key molecular regulation system for bone remodelling. RANKL, a member of the tumor necrosis factor (TNF) family, is the main stimulatory factor for the formation of mature osteoclasts and is essential for their survival. Therefore, an increase in RANKL expression leads to bone resorption and bone loss. RANKL is produced by osteoblastic lineage cells and activated T lymphocytes. It activates its specific receptor RANK which is located on osteoclasts and dendritic cells.
The effects of RANKL are counteracted by OPG which is secreted by various tissues and acts as an endogenous soluble receptor antagonist.
Imbalances of the RANKL/OPG system have been related to the pathogenesis of Paget's disease, benign and malignant bone tumors, postmenopausal osteoporosis, rheumatoid arthritis, bone metastases and hypercalcemia. It was shown in several studies that in animal models restoring of the RANKL/OPG balance (e.g. by administering OPG) reduces the severity of these disorders.
It has been shown, that RANKL is produced as a membrane-bound protein on murine osteoblasts/stromal cells, and cleaved into a soluble form by a metalloprotease. Stimulators of the osteoclastogenesis such as IL-1beta, IL-6, IL-11, IL-17, and TNF-alpha, increase the expression of RANKL and decrease OPG expression in osteoblasts/stromal cells. Cytokines inhibiting the osteoclastogenesis such as IL-13, INF-gamma, and TGF-beta1, suppress the expression of RANKL and stimulated OPG expression.
##Molecular structure:##
sRANKL is a part of the TNF superfamily with high similarity to other members of that protein species. (SwissProt Nr. O14788). Two isoforms are produced by alternate splicing, a type II membrane protein (ISOFORM 1, 317 AA, MW 35.5 kD), and a secreted molecule (ISOFORM 2, 244 AA, MW 27.7kD), lacking the cytoplasmic and transmembrane domain. Although both forms are bioactive, the membrane bound protein seems to be the homeostatic form, while the production of soluble RANKL signals pathological conditions.
##Indications##
1) Postmenopausal and senile osteoporosis
2) Diseases with locally increased bone resorption activity
3) Paget′s disease
4) Periodontal disease
5) Inflammatory diseases
6) Immunological disorders
7) Arthritis
8) Oncology