INTERLEUKIN 1 BETA HUMAN ELISA

BRAND:                  DEMEDITEC DIAGNOSTICS GMBH

PRODUCT CODE: DE4437

AVAILABILITY:

DESCRIPTION

• CE certified for IVD use

• 96 well ELISA microplate

• Incubation time: 2 h 15 min

• Range: 24 - 1,166 pg/ml

• Sensitivity: 0.35 pg/ml

• Sample size: 200 µl

• Sample type: serum, plasma

• Substrate: TMB 450nm

1. INTENDED USE

Immunoenzymetric assay for the in vitro quantitative measurement of human Interleukin 1beta (IL-1beta) in serum and plasma.

2. CLINICAL BACKGROUND

A. Biological activities

Human interleukin-1 (IL-1) is a key mediator of the host response to various infectious, inflammatory and immunologic challenges. Two distinct polypeptides, IL-1α and IL-1ß, mediate IL-1 biological activities and bind to the same cell surface receptor. Both are initially synthesized as 31-kDA intracellular precursors that are subsequently found as mature proteins of 17 kDA in monocyte supernates. Membrane-bound IL-1 has also been described and may account for a part of IL-1 mediated local effects. The primary sources of IL-1 are blood monocytes and tissue macrophages. Other specialized cells such as T- and B-lymphocytes, various epithelial, endothelial and some mesenchymal cells can also produce IL-1. IL-1ß is the major form secreted by monocytes and macrophages which are believed to be the main source of circulating (plasma) IL-1. Inhibitions of IL-1 activity have been described in plasma and other biological fluids. IL-1 affects several unrelated tissues and is a main mediator of the "acute phase" inflammatory responses characterised by alterations in metabolic, endocrinologic and immunologic functions. This cytokine has an essential role in T-cell activation, providing one of the necessary signals for IL-2 (T-cell growth factor) production. It is the main mediator of inflammatory processes by acting on the nervous system (fever, sleep, anorexia), on bone marrow-derived cells (chemotaxis and/or activation of neutrophils, monocytes and lymphocytes) and on various tissues (fibroblast proliferation, resorption of cartilage and bone matrices, glial cell proliferation, stimulation of endothelial cell procoagulant activity, etc.). Most of these activities are directly attributable to IL-1ß, but others are mediated in collaboration with other cytokines such as IL-6, interferons, and tumor necrosis factor. IL-1 stimulates the production or acts synergistically with these cytokines and the final biological activity is thus the result of a network of interactions between these various mediators.

B. Clinical application

The biological properties of IL-1ß and its key role in inflammatory processes suggest its involvement in the pathogenesis of many diseases. Indeed, high amounts of IL-1 are found in the joint effusions of some patients with rheumatoid and non-rheumatoid inflammatory joint diseases, in infectious pleural or peritoneal fluids, and in the drainage fluid of patients undergoing chronic diabetes, periodontal diseases, etc. Although little or no IL-1ß is normally detected in human plasma or serum obtained from healthy, rested human subjects, elevated levels have been reported in the circulation of febrile or septic patients, in patients with Crohn's disease, during graft rejection, in healthy volunteers after extended exercise and in women following ovulation. Studies based on in vitro production of IL-1 by isolated blood leukocytes have demonstrated reduced IL-1 production in malnourished patients and cancer patients with large tumor burdens. Hence, this immunoassay for IL-1ß is an important tool to study macrophage activation and to investigate the role of IL-1ß in various (physiological or pathological) immune and inflammatory processes.

3. PRINCIPLES OF THE METHOD

The IL-1beta ELISA is a solid phase Enzyme Amplified Sensitivity Immunoassay performed on microtiterplate. The assay uses monoclonal antibodies (MAbs) directed against distinct epitopes of IL-1β. Calibrators and samples react with the capture monoclonal antibody (MAb 1) coated on microtiter well and with a monoclonal antibody (MAb 2) labelled with horseradish peroxidase (HRP). After an incubation period allowing the formation of a sandwich: coated MAb 1 – human IL-1β – MAb 2 – HRP, the microtiterplate is washed to remove unbound enzyme labelled antibody. Bound enzyme-labelled antibody is measured through a chromogenic reaction. Chromogenic solution (TMB) is added and incubated. The reaction is stopped with the addition of Stop Solution and the microtiterplate is then read at the appropriate wavelength. The amount of substrate turnover is determined colourimetrically by measuring the absorbance, which is proportional to the IL-1β concentration.

A calibration curve is plotted and IL-1β concentration in samples is determined by interpolation from the calibration curve. The use of the ELISA reader (linearity up to 3 OD units) and a sophisticated data reduction method (polychromatic data reduction) result in a high sensitivity in the low range and in an extended calibration range.