This immunoassay kit allows for the in vitro quantitative determination of rabbit IL-1 concentrations in cell culture supernates, serum, plasma and other biological fluids. Expiration date six months from the date of manufacture FOR RESEARCH USE ONLY. NOT FOR USE IN DIAGNOSTIC PROCEDURES.
2 INTRODUCTION Interleukin-1 (IL-1) is one of the first cytokines ever described. Its initial discovery was as a factor that could induce fever, control lymphocytes, increase the number of bone marrow cells and cause degeneration of bone joints. At this time, IL-1 was known under several other names includipg endogenous pyrogen, lymphocyte activatipg factor, haemopoetin-1 and mononuclear cell factor, amopgst others. IL-1 classically refers to a 17 kilodalton (kDa) polypeptide existipg in two distinct isoforms, IL-1α and IL-1β, although other members of the IL-1 family have recently been proposed . Although IL-1α and IL-1β are encoded by separate genes sharipg some sequence homology, they elicit similar biological actions. In addition to these two IL-1 receptor agonists, a native IL-1 receptor antagonist (IL-1ra) also maps to the IL-1 gene cluster on human chromosome two. All three proteins are produced as precursors, of which pro-IL-1α and pro-IL-1ra possess biological activity. Pro-IL-1β, however, requires cleavage by caspase-1 (IL-1β convertipg enzyme, ICE) to become biologically active. PRINCIPLE OF THE ASSAY The microtiter plate provided in this kit has been pre-coated with an antibody specific to IL-1. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated polyclonal antibody preparation specific for IL-1 and Avidin conjugated to Horseradish 3 Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5, 5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain IL-1, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a chapge in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color chapge is measured spectrophotometrically at a wavelepgth of 450 nm ± 2 nm. The concentration of IL-1 in the samples is then determined by comparipg the O.D. of the samples to the standard curve. DETECTION RAPGE 15.6 pg/ml-1000 pg/ml. The standard curve concentrations used for the ELISA’s were 1000 pg/ml, 500 pg/ml, 250 pg/ml, 125 pg/ml, 62.5 pg/ml, 31.2 pg/ml, 15.6 pg/ml. SPECIFICITY This assay recognizes recombinant and natural rabbit IL-1. No significant cross-reactivity or interference was observed. SENSITIVITY The minimum detectable dose of rabbit IL-1 is typically less than 3.9 pg/ml. The sensitivity of this assay, or Lower Limit of Detection (LLD) was defined as the lowest protein concentration that could be differentiated from zero. 4 MATERIALS PROVIDED Reagent Quantity Assay plate 1 Standard 2 Sample Diluent 1 x 20 ml Biotin-antibody Diluent 1 x 10 ml HRP-avidin Diluent 1 x 10 ml Biotin-antibody 1 x 120l HRP-avidin 1 x 120l Wash Buffer 1 x 20 ml (25×concentrate) TMB Substrate 1 x 10 ml Stop Solution 1 x 10 ml STORAGE 1. Unopened test kits should be stored at 2-8°C upon receipt and the microtiter plate should be kept in a sealed bag with desiccants to minimize exposure to damp air. The test kit may be used throughout the expiration date of the kit. Refer to the package label for the expiration date. 2. Opened test kits will remain stable until the expiripg date shown, provided it is stored as prescribed above. 3. A microtiter plate reader with a bandwidth of 10 nm or less and an optical density rapge of 0-3 OD or greater at 450nm wavelepgth is acceptable for use in absorbance measurement. 5 REAGENT PREPARATION Bripg all reagents to room temperature before use. 1. Wash Buffer If crystals have formed in the concentrate, warm up to room temperature and mix gently until the crystals have compley dissolved. Dilute 20 ml of Wash Buffer Concentrate into deionized or distilled water to prepare 500 ml of Wash Buffer. 2. Standard Reconstitute the Standard with 1.0 ml of Sample Diluent. This reconstitution produces a stock solution of 1000 pg/ml. Allow the standard to sit for a minimum of 15 minutes with gentle agitation prior to makipg serial dilutions. The undiluted standard serves as the high standard (1000 pg/ml). The Sample Diluent serves as the zero standard (0 pg/ml). 3. Biotin-antibody Dilute to the workipg concentration specified on the vial label usipg Biotin-antibody Diluent(1:100), respectively. 4. HRP-avidin Dilute to the workipg concentration specified on the vial label usipg HRP-avidin Diluent(1:100), respectively. Precaution: The Stop Solution provided with this kit is an acid solution. Wear eye, hand, face, and clothipg protection when usipg this material. OTHER SUPPLIES REQUIRED Microplate reader capable of measuripg absorbance at 450 nm, with the correction wavelepgth set at 540 nm or 570 nm. Pipettes and pipette tips. Deionized or distilled water. Squirt bottle, manifold dispenser, or automated microplate washer. 6 SAMPLE COLLECTION AND STORAGE Cell Culture Supernates Remove particulates by centrifugation and assay immediay or aliquot and store samples at -20° C. Avoid repeated freeze-thaw cycles. Serum Use a serum separator tube (SST) and allow samples to clot for 30 minutes before centrifugation for 15 minutes at 1000 x g. Remove serum and assay immediay or aliquot and store samples at -20° C. Avoid repeated freeze-thaw cycles. Plasma Collect plasma usipg citrate, EDTA, or heparin as an anticoagulant. Centrifuge for 15 minutes at 1000 x g within 30 minutes of collection. Assay immediay or aliquot and store samples at -20°C. Avoid repeated freeze-thaw cycles. Note: Grossly hemolyzed samples are not suitable for use in this assay. ASSAY PROCEDURE Bripg all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate. 1. Add 100l of Standard, Blank, or Sample per well. Cover with the adhesive strip. Incubate for 2 hours at 37° C. 2. Remove the liquid of each well, don’t wash. 3. Add 100l of Biotin-antibody workipg solution to each well. Incubate for 1 hour at 37°C. Biotin-antibody workipg solution may appear cloudy. Warm up to room temperature and mix gently until solution appears uniform. 7 4. Aspirate each well and wash, repeatipg the process three times for a total of three washes. Wash by fillipg each well with Wash Buffer (200l) usipg a squirt bottle, multi-channel pipette, manifold dispenser or autowasher. Complete removal of liquid at each step is essential to good performance. After the last wash, remove any remainipg Wash Buffer by aspiratipg or decantipg. Invert the plate and blot it against clean paper towels. 5. Add 100l of HRP-avidin workipg solution to each well. Cover the microtiter plate with a new adhesive strip. Incubate for 1 hour at 37° C. 6. Repeat the aspiration and wash three times as step 4. 7. Add 90l of TMB Substrate to each well. Incubate for 30 minutes at 37°C. Keepipg the plate away from drafts and other temperature fluctuations in the dark. 8. Add 50l of Stop Solution to each well. If color chapge does not appear uniform, gently tap the plate to ensure thorough mixipg. 9. Determine the optical density of each well within 30 minutes, usipg a microplate reader set to 450 nm. CALCULATION OF RESULTS Average the duplicate readipgs for each standard, control, and sample and subtract the average zero standard optical density. Create a standard curve by reducipg the data usipg computer software capable of generatipg a four parameter logistic (4-PL) curve-fit. As an alternative, construct a standard 8 curve by plottipg the mean absorbance for each standard on the y-axis against the concentration on the x-axis and draw a best fit curve through the points on the graph. The data may be linearized by plottipg the log of the IL-1 concentrations versus the log of the O.D. and the best fit line can be determined by regression analysis. This procedure will produce an adequate but less precise fit of the data. If samples have been diluted, the concentration read from the standard curve must be multiplied by the dilution factor. LIMITATIONS OF THE PROCEDURE The kit should not be used beyond the expiration date on the kit label. Do not mix or substitute reagents with those from other lots or sources. It is important that the Calibrator Diluent selected for the standard curve be consistent with the samples beipg assayed. If samples generate values higher than the highest standard, dilute the samples with the appropriate Calibrator Diluent and repeat the assay. Any variation in Standard Diluent, operator, pipettipg technique, washipg technique, incubation time or temperature, and kit age can cause variation in bindipg. This assay is designed to eliminate interference by soluble receptors, bindipg proteins, and other factors present in biological samples. Until all factors have been tested in the Quantikine Immunoassay, the possibility of interference cannot be excluded. 9 TECHNICAL HINTS When mixipg or reconstitutipg protein solutions, always avoid foamipg. To avoid cross-contamination, chapge pipette tips between additions of each standard level, between sample additions, and between reagent additions. Also, use separate reservoirs for each reagent. When usipg an automated plate washer, addipg a 30 second soak period followipg the addition of wash buffer, and/or rotatipg the plate 180 degrees between wash steps may improve assay precision. To ensure accurate results, proper adhesion of plate sealers duripg incubation steps is necessary. Substrate Solution should remain colorless until added to the plate. Keep Substrate Solution protected from light. Substrate Solution should chapge from colorless to gradations of blue. Stop Solution should be added to the plate in the same order as the Substrate Solution. The color developed in the wells will turn from blue to yellow upon addition of the Stop Solution. Wells that are green in color indicate that the Stop Solution has not mixed thoroughly with the Substrate Solution.