The microtiter plate provided in this human IL-11 ELISA kit has been pre-coated with a monoclonal antibody specific to IL-11. Standards or samples provided in this human IL-11 ELISA kit are then added to the appropriate microtiter plate wells and incubated. After washing to remove unbound IL-11 and other components of the sample, biotin-conjugated polyclonal antibody specific to IL-11 is added and incubated. If present, IL-11 will bind and become immobilized by the antibody pre-coated on the wells and then become “sandwiched” by the biotin conjugate. In order to quantitatively determine the amount of IL-11 present in the sample, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Avidin is a tetramer containing four identical subunits, each having a high affinity-binding site for biotin. The wells are thoroughly washed to remove all unbound HRP-conjugated Avidin and a TMB (3,3'5,5' tetramethyl-benzidine) substrate solution is added to each well. The enzyme (HRP) and substrate are allowed to react over a short incubation period. Only those wells that contain IL-11, biotin-conjugated antibody, and enzyme-conjugated Avidin will exhibit a change in colour. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the colour change is measured spectrophotometrically at a wavelength of 450 nm ± 2 nm.

In order to measure the concentration of IL-11 in the samples, this human IL-11 ELISA kit includes two calibration diluents (Calibrator Diluent I for serum/plasma testing and Calibrator Diluent II for cell culture supernatant testing). According to the testing system, the standard provided is diluted (2-fold) with the appropriate Calibrator Diluent and assayed at the same time as the samples. This allows the operator to produce a standard curve of Optical Density (O.D) versus IL-11 concentration (pg/mL). The concentration of IL-11 in the samples is then determined by comparing the O.D. of the samples to the standard curve. The minimum detectable quantities of human IL-10 using this human IL-11 ELISA kit as observed by the standard curve generated for both Calibrator Diluent I and Calibrator Diluent II are 4.0 pg/mL and 3.0pg/mL respectively. The two standard deviations above the mean optical density of the 16 replicates of the zero standard were defined as the minimum detectable quantities.

IL-11 exerts biological activity through IL-11 receptor by utilizing the gp130 molecule as the signaling component of its receptor. Interleukin 11 (IL-11) is a highly conserved precursor protein of 19kDa with 199 amino acids. The first 21 amino acids are a typical leader sequence for secreted proteins. When the 178 amino acid protein is released from the cell, the first 21 amino acids are removed. IL-11 is thermally stable and contains no cysteine residues. IL-11 has activity in bone metabolism and activity in protection and restoration of the gastrointestinal mucosa. Human endometrial stromal cells produce biologically active IL-11, which promotes progesterone-induced decidualization. Therefore, the IL-11 has both paracrine and autocrine actions on human endometrial stromal cells and plays an important role in preparing the human endometrium for implantation. Reports indicate that abnormal IL-11 levels in serum or plasma is related to immune thrombocytopenia, rheumatoid arthritis, and urogenital infection. Immunoreactive IL-11 has also been linked to aseptic loosening of total hip replacement implants. IL-11 has been demonstrated to improve platelet recovery after chemotherapy-induced thrombocytopenia, induce acute phase proteins, modulate antigen-antibody responses, participate in the regulation of bone cell proliferation and differentiation and could be use as a therapeutic for osteoporosis.

This human IL-11 ELISA kit is to be used for the in vitro quantitative determination of human Interleukin 11 (IL-11) concentrations in serum, plasma, and cell culture supernatant. This sandwich human IL-11 ELISA kit can detect both natural and recombinant human IL-11. The following factors were assayed for cross-reactivity at 50 ng/mL in Calibrator Diluent I and Calibrator Diluent II. Preparations of the following factors at 50 ng/mL in a mid-range rhIL-11Control were tested for interference. No significant cross-reactivity or interference was identified using this human IL-11 ELISA kit. This human IL-11 ELISA kit immunoassay is calibrated against NIBSC Standard (Reference preparation) Code No. 92/788. This human IL-11 ELISA kit is intended for LABORATORY RESEARCH USE ONLY and is not for use in diagnostic or therapeutic procedures. Forty serum, EDTA plasma, heparin and citrate plasma samples were tested in this human IL-11 ELISA kit assay. All samples measured less than the lowest IL-11 standard, 50 pg/mL.

Compared to other interleukins, IL-11 relatively under-characterized.