Human lipocalin-2/NGAL ELISA Kit

Principle of the Assay

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for Lipocalin-2/NGAL has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any Lipocalin-2/NGAL present is bound by the immobilized antibody. Following incubation unbound samples are removed during a wash step, and then a detection antibody specific for Lipocalin-2/NGAL is added to the wells and binds to the combination of capture antibody-Lipocalin-2/NGAL in sample. Following a wash to remove any unbound combination, and enzyme conjugate is added to the wells. Following incubation and wash steps a substrate is added. A coloured product is formed in proportion to the amount of Lipocalin-2/NGAL present in the sample. The reaction is terminated by addition of acid and absorbance is measured at 450nm. A standard curve is prepared from seven Lipocalin-2/NGAL standard dilutions and Lipocalin-2/NGAL sample concentration determined.

For Use with serum, plasma and cell culture supernatants. For Research Use Only. Not for use in diagnostic procedures.

Target Information

Members of the Lipocalin family have limited sequence identity, but share a highly conserved fold with an eight-stranded anti-parallel β barrel motif that encloses an internal ligand-binding site. They are known for their actions as transporters that carry small hydrophobic molecules such as steroid hormones, vitamins, odorants, and metabolic products. Lipocalin-2, also known as Neutrophil Gelatinase-associated Lipocalin (NGAL) or Siderocalin, was originally identified as a component of neutrophil granules. Since then, its expression has been observed in most tissues, and its synthesis is induced in epithelial cells during inflammation. Lipocalin-2 has been implicated in a variety of cellular processes including the innate immune response, differentiation, tumorigenesis, and cell survival. It is a 25 kDa protein existing in monomeric, homodimeric, and heterodimeric forms, the latter in association with human matrix metalloproteinase 9 (MMP-9). Its association with MMP-9 may modulate protease activity by protecting MMP-9 from degradation. The mouse ortholog (also known as 24p3) shares 62% sequence identity at the amino acid level.

The functions of Lipocalin-2 continue to be elucidated. Studies indicate that it binds bacterial catecholate siderophores bound to ferric ions. This suggests that Lipocalin-2 may act as a bacteriostatic agent by binding bacterial siderophores and limiting bacterial iron supply. This is supported by the observation that mouse Lipocalin-2 is induced in immune cells following Toll-like receptor activation, and Lipocalin-2 mouse knockouts exhibit decreased ability to counter bacterial infection. Lipocalin-2 may also regulate iron uptake into mammalian cells. In the kidney, Lipocalin-2-mediated iron trafficking may be involved in both development and protection from renal injury. Megalin, a member of the LDL receptor family, and 24p3 R have been reported as endocytic receptors for Lipocalin-2. It should be noted that the effects of Lipocalin-2 on cells might be context-dependent. For instance, it has been shown to act as both a survival factor and a pro-apoptotic factor, and its induction by pro-inflammatory cytokines may vary between mouse and human.

Lipocalin-2 has been associated with several pathological processes. For instance, it is upregulated in psoriatic skin in comparison to uninvolved control skin, and Lipocalin-2 suppresses red blood cell production in models of anemia. Lipocalin-2 is elevated in patients with severe acute respiratory syndrome (SARS), and may act as a biomarker for acute renal injury. It has been associated with several tumor types as well, including breast, ovarian, colorectal, and pancreatic cancers. Its function in cancer is unclear, although the invasive and metastatic behavior of tumor cells is suppressed by Lipocalin-2 in models of breast and colon cancer.

GENE ID 3934
SWISS PROT P80188
SYNONYMS p25; 24p3; MSFI; NGAL

Materials Supplied

Kit Components 96 Wells Quantity/Size
Aluminium pouches with a Microwell Plate coated with monoclonal antibody to human Lipocalin-2/NGAL (8﹡12) 1 plate
Human Lipocalin-2/NGAL Standard lyophilized, 2500 pg/ml upon reconstitution 2 vials
Concentrated Biotin-Conjugate anti-human Lipocalin-2/NGAL monoclonal antibody 2 vials
Streptavidin-HRP solution 2 vials
Standard /sample Diluent 2 bottles
Biotin-Conjugate antibody Diluent 1 bottle
Streptavidin-HRP Diluent 1 bottle
Wash Buffer Concentrate 20x (PBS with 1% Tween-20) 1 bottle
Substrate Solution 1 vial
Stop Solution 1 vial
Adhesive Films 4 pieces
Product data sheet 1 copy

Storage

Storage Store at 2 - 8°C

Performance Characteristics

REPEATABILITY The coefficient of variation of both intra-assay and inter-assay were less than 10%.
SENSITIVITY The minimum detectable dose was 40pg/mL.
ASSAY RANGE 78 - 5000pg/mL
SPECIFICITY This assay recognizes both natural and recombinant human Lipocalin-2/NGAL. The factors listed below were prepared at 50ng/ml in Standard /sample Diluent and assayed for cross-reactivity and no significant cross-reactivity or interference was observed.
Factors assayed for cross-reactivity
Recombinant human COX-2, Lipocalin-1, MMP-9
Recombinant mouse Lipocalin-2