HEPATITIS E – HEV-Ab
Contents
1. Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Reagents preparation Allow the reagents and samples to reach room temperature 18 30 C for at least 15 30 minutes Check the Wash buffer concentrate for the presence of salt crystals If crystals have formed in the solution resolubilize by warming at 37 C until crystals dissolve Dilute the stock Wash Buffer 1 to 20 with distilled or deionized water Use only clean vessels to dilute the buffer Numbering Wells Set the strips needed in strip holder and number sufficient number of wells including three Negative control e g B1 C1 D1 two Positive control e g E1 F1 and one Blank A1 neither samples nor HRP Conjugate should be added into the Blank well If the results will be determined by using dual wavelength plate reader the requirement for use of Blank well could be omitted Use only number of strips required for the test Adding Diluent Add 50ul Specimen Diluent into each well Adding Sample Add 50ul of Positive control Negative control and Specimen into their respective wells Note Use a_ separate disposal pipette tip for each specimen Negative Control Positive as to avoid cross contamination Incubating Sample Cover the plate with the plate cover and incubate for 30 minutes at 37 C It is recommended to use thermostat controlled water tank to assure the temperature stability and humidity during the incubation If dry incubator is used do not op2. Therefore handle reagents and specimens with extreme caution as if capable of transmitting infectious diseases Strict adherence to GLP Good Laboratory Practice regulations can ensure the personal safety Never eat drink smoke or apply cosmetics in the assay laboratory Bovine derived sera may have been used in this kit Bovine serum albumin BSA and fetal calf sera FCS are derived from animals from BSE TSE free geographical areas The pipette tips vials strips and sample containers should be collected and autoclaved for 1hour at 121 C or treated with 10 sodium hypochlorite for 30minutes to decontaminate before any further steps for disposal The Stop solution 2M H2SO is a strong acid Corrosive Use it with appropriate care Wipe up spills immediately or wash with water if come into contact with the skin or eyes ProClin 300 used as a preservative can cause sensation of the skin The enzymatic activity of the HRP conjugate might be affected from dust reactive chemical and substances like sodium hypochlorite acids alkalis etc Do not perform the assay in the presence of such substances 20 Materials Safety Data Sheet MSDS available upon request If using fully automated microplate processing system during incubation do not cover the plates with the plate cover The tapping out of the remainders inside the plate after washing can also be omitted ASSAY PROCEDURE Step 1 Step 2 Step 3 Step 4
3. required for assaying within 3 days should be stored frozen 20 C or lower Multiple freeze thaw cycles should be avoided For shipment samples should be packaged and labeled in accordance with the existing local and international regulations for transport of clinical samples and ethological agents SPECIAL INSTRUCTIONS FOR WASHING 1 A good washing procedure is essential to obtain correct and precise analytical data 2 lt is therefore recommended to use a good quality ELISA microplate washer maintained at the best level of washing performances In general no less than 5 automatic washing cycles of 350 400ul well are sufficient to avoid false positive reactions and high background 3 To avoid cross contaminations of the plate with sample or HRP conjugate after incubation do not discard the content of the wells but allow the plate washer to aspirate it automatically 4 Anyway we recommend calibrating the washing system on the kit itself in order to match the declared analytical performances Assure that the microplate washer liquid dispensing channels are not blocked or contaminated and sufficient volume of Wash buffer is dispensed each time into the wells 5 In case of manual washing we suggest to carry out 5 cycles dispensing 350 400ul well and aspirating the liquid for 5 times If poor results high background are observed increase the washing cycles or soaking time per well 6 In any case the liquid aspirated ou
4. For Research Use Only MpressBio HEPATITIS E HEV Ab Catalog WE7396 Not for Diagnostic Use ELISA KIT FOR TOTAL ANTIBODIES TO HEPATITIS E VIRUS Two step Incubation Double Antigen Sandwich Principle INSTRUCTIONS FOR USE This HEV Ab ELISA kit is an enzyme linked immunosorbent assay for in vitro qualitative detection of total antibodies IgG IgM etc to hepatitis E virus in animal serum or plasma For research use only SUMMARY Hepatitis E virus HEV is a non enveloped single stranded RNA virus identified in 1990 Infection with HEV induces acute or sub clinical liver diseases similar to hepatitis A HEV infections endemic and frequently epidemic in developing countries is seen also in developed countries in a sporadic form with or without a history of traveling to endemic area The overall case fatality is 0 5 3 and much higher 15 25 among pregnant women A hypothesis that HEV infection is a zoonosis was presented in 1995 Then a swine HEV and later an avian HEV were identified and sequenced separately in 1997 and 2001 Since then HEV infection include anti HEV viremia and feces excretion of HEV was seen in a wide variety of animals i e swine rodents wild monkeys deer cow goats dogs and chicken in both the developing and developed countries A direct testimony was reported that the consumption of uncooked dear meat contaminated with HEV led to acute hepatitis E in human and HEV genome s
5. Meng XJ Purcell RH Halbur PG et al A novel virus in swine is closely related to the human hepatitis E virus Proc Natl Acad Sci USA 1997 94 9860 9865 4 Tei S Kitajima N Takahashi K et al Zoonotic transmission of hepatitis E virus from deer to human beings Lancet 2003 362 9381 371 5 Zheng YJ Zhang J Xia NS A debate about that hepatitis E is a zoonosis Chinese J Zoonosis in press 6 Wang YC Zhang HY Xia NS et al Prevalence Isolation and Partial Sequence Analysis of Hepatitis E Virus From Domestic Animals in China J Med Virol 2002 67 516 521 7 Zhang JZ Ng MH Xia NS et al Conformational Antigenic Determinants Generated by Interactions Between a Bacterially Expressed Recombinant Peptide of the Hepatitis E Virus Structural Protein J Med Virol 2001 64 125 132 8 Stanley WK Zhang JZ Zhuang H et al A bacterially expressed p a recombinant peptide of virus capsid protein J Virol 2003 in press 9 Zhang J Ge SX Huang GY et al Evaluation of antibody based and nucleic acid based assays for diagnosis of hepatitis E virus infection in a rhesus monkey model J Med Virol 2003 in press 10 He ZQ Ge SX Qiu Y et al Establishment and primary application of double antigen sandwich ELISA for detection of hepatitis E virus antibody Chinese J Zoonosis 2002 18 6 18 21 Express Biotech International P O BOX 458 Thurmont MD 21788 USA Tel 301 228 2444 Fax 301 560 6570 Toll Free 888 562 8914 www xpressb
6. ater 2 Disposable gloves and timer 3 Appropriate waste containers for potentially contaminated materials 4 Disposable V shaped troughs 5 Dispensing system and or pipette single or multichannel disposable pipette tips 6 Absorbent tissue or clean towel N Dry incubator or water bath 37 0 5 C 8 Microshaker for dissolving and mixing conjugate with samples Microwell plate reader single wavelength 450nm or dual wavelength 450nm and 630nm 10 Microwell aspiration wash system o SPECIMEN COLLECTION TRANSPORTATION AND STORAGE 1 Sample Collection Either fresh serum or plasma samples can be used for this assay Blood collected by venipuncture should be allowed to clot naturally and completely the serum plasma must be separated from the clot as early as possible as to avoid hemolysis of the RBC Care should be taken to ensure that the serum samples are clear and not contaminated by microorganisms Any visible particulate matters in the sample should be removed by centrifugation at 3000 RPM for at least 20 minutes at room temperature or by filtration on 0 22u filters Plasma samples collected into EDTA sodium citrate or heparin may be tested but highly lipaemic icteric or hemolized samples should not be used as they could give erroneous results in the assay Do not heat inactivate samples This can cause sample deterioration 2 Transportation and Storage Store samples at 2 8 C Samples not
7. ature 18 30 C before use 4 Shake reagent gently before and return to 2 8 C immediately after use 5 Use only sufficient volume of sample as indicated in the 6 Do not touch procedure steps Failure to do so may cause in low sensitivity of the assay the bottom exterior of the wells fingerprints or scratches may interfere with microwell reading 7 When reading the results ensure that the plate bottom is dry and there are no air bubbles inside the wells 8 Never allow the microplate wells to dry after the washing step Immediately proceed to the next step Avoid the formation of air bubbles when adding the reagents 9 Avoid assay steps long time interruptions Assure same 10 11 12 13 14 15 16 17 18 19 working conditions for all wells Calibrate the pipette frequently to assure the accuracy of samples reagents dispensing Always use different disposal pipette tips for each specimen and reagents as to avoid cross contaminations Never pipette solutions by mouth The use of automatic pipettes is recommended Assure that the incubation temperature is 37 C inside the incubator When adding samples avoid touching the wells bottom with the pipette tip When reading the results with a plate reader it is recommended to determine the absorbance at 450nm or at 450nm with reference at 630nm All specimens from animal origin should be considered as potentially infectious
8. blue colored product The amount of color intensity can be measured and is proportional to the amount of antibody captured in the wells and to the sample respectively Wells containing samples negative for HEV remain colorless COMPONENTS 96 Tests MICROWELL PLATE 1 plate Blank microwell strips fixed on a white strip holder The plate is sealed in aluminum pouch with desiccant 8x12 12x8 well strips wells per plate Each well contains recombinant HEV antigens The microwell strips can be broken to be used separately Place unused wells or strips in the plastic sealable storage bag together with the desiccant and return to 2 8 C NEGATIVE CONTROL 1 vial Blue colored liquid filled in a vial with green screw cap 0 5ml per vial Protein stabilized buffer tested non reactive for HEV Ab Preservatives 0 1 ProClin 300 Ready to use as supplied Once open stable for one month at 2 8 C POSITIVE CONTROL 1 vial Red colored liquid filled in a vial with red screw cap 0 5ml per vial HEV Ab diluted in protein stabilized buffer Preservatives 0 1 ProClin 300 Ready to use as supplied Once open stable for one month at 2 8 C SPECIMEN DILUENT 1 vial Green colored liquid filled in a white vial with blue screw cap 6ml per vial Protein stabilized buffer casein and sucrose solution Ready to use as supplied Once open stable for one month at 2 8 C HRP CONJUGATE REAGENT 1 vial Red colored liquid filled in a white via
9. ces for mistakes kits beyond the expiry date bad washing procedures contaminated reagents incorrect assay procedure steps insufficient aspiration during washing failure to add samples or reagents equipment timing volumes sample nature and quality 7 The prevalence of the marker will affect the assay s predictive values 8 This is a qualitative assay and the results cannot be use to measure antibodies concentrations INDICATIONS OF INSTABILITY OR DETERIORATION OF THE REAGENTS 1 Values of the Positive or Negative controls which are out of the indicated Quality control range are indicator of possible deterioration of the reagents and or operator or equipment errors In such case the results should be considered as invalid and the samples must be retested In case of constant erroneous results classified as due to deterioration or instability of the reagents 2 If after mixing of the Chromogen A and B solutions into the wells the the color of the mixture turns blue within few minutes do not continue carrying out the testing and replace the reagents with fresh ones REFERENCES 1 Reyes GR Purdy MA Kim JP et al Isolation of a cDNA from the virus responsible for enterically transmitted non A non B hepatitis Science 1990 247 1335 1339 2 Clayson E Innis B Myint K et al Detection of hepatitis E virus infections among domestic swine in the Kathmandu Valley of Nepal Am J Trop Med Hyg 1995 53 228 232 3
10. en the door frequently Washing At the end of the incubation remove and discard the plate cover Wash each well 5 times with diluted Wash buffer Each time allow the microwells to soak for 30 60 seconds After the final washing cycle turn down the plate onto blotting paper or clean towel and tap the plate to remove any remainders Adding HRP Conjugate Add 100ul Conjugate to each well except the Blank Incubating Cover the plate with the plate cover and incubate the plate for 30 minutes at 37 C Washing At the end of the incubation remove and discard the plate cover Wash each well 5 times with diluted Wash Buffer as in Step6 Coloring Dispense 50 ul of Chromogen A and 50ul Chromogen B solution into each well HRP including the Blank and mix by tapping the plate gently Incubate the plate at 37 C for 15 minutes avoiding light The enzymatic reaction between the Chromogen A B solutions produces blue color in Positive control and HEV Ab positive sample wells Step 11 Stopping Reaction Using a multichannel pipette or manually add 50ul Stop Solution into each well and mix gently by tapping the plate Intensive yellow color develops in Positive control and HEV Ab positive sample wells Step 12 Measuring the Absorbance Calibrate the plate reader with the Blank well and read the absorbance at 450nm If a dual filter instrument is used set the reference wavelength at 630nm Calculate the Cut off value and evaluate the result
11. equences can be detected in pork livers available in the supermarkets in Japan With the discovery of conformational epitopes in HEV HEV serology was further explored and understood The phenomenon of long lasting and protective antibodies to HEV was observed which greatly enhance the understanding to the diagnosis epidemiology zoonosis related studies and vaccine development PRINCIPLE OF THE ASSAY This HEV Ab ELISA kit uses polystyrene microwell strips pre coated with recombinant HEV antigens HEV Ag corresponding to structural proteins ORF 2 of the native virus Serum or plasma sample is added into the microwells In case of presence of HEV Ab in the sample the pre coated antigens will be bound to the antibody and during the first incubation step the specific immunocomplex formed is captured on the solid phase After washing to remove unbound sample second recombinant HEV antigen conjugated to Horseradish Peroxidase HRP is added into the wells During the second incubation step this antigen will bind to the second variable domain of the HEV antibodies if they have been captured by HEV antigen during the first incubation step The unbound HRP conjugate is removed during washing and Chromogen solutions containing Tetramethylbenzidine TMB and urea peroxide are added into the wells In presence of the antigen antibody antigen HRP sandwich complex the colorless Chromogens are hydrolyzed by the bound HRP Conjugate to a
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13. l with red screw cap 12ml per vial Horseradish peroxidase conjugated recombinant HEV antigens Ready to use as supplied Once open stable for one month at 2 8 C STOCK WASH BUFFER 1 bottle Colorless liquid filled in a clear bottle with white screw cap 50ml per bottle pH 7 4 20 x PBS Containing Tween 20 as a detergent DILUTE BEFORE USE The concentration must be diluted 1 to 20 with distilled deionized water before use Once diluted stable for one week at room temperature or for two weeks when stored at 2 8 C CHROMOGEN SOLUTION A 1 vial Colorless liquid filled in a white vial with green screw cap 7ml per vial Urea peroxide solution Ready to use as supplied Once open stable for one month at 2 8 C CHROMOGEN SOLUTION B 1 vial Colorless liquid filled in a black vial with black screw cap 7ml per vial TMB solution Tetramethylbenzidine dissolved in citric acid Ready to use as supplied Once open stable for one month at 2 8 C STOP SOLUTION 1 vial Colorless liquid filled in a white vial with white screw cap 7ml per vial Diluted sulfuric acid solution 2 0 M H2804 Ready to use as supplied PLASTIC SEALABLE BAG 1 unit For enclosing the strips not in use CARDBOARD PLATE COVER 2 sheets To cover the plates during incubation and prevent evaporation or contamination of the wells PACKAGE INSERTS 1 copy ADDITIONAL MATERIALS AND INSTRUMENTS REQUIRED BUT NOT PROVIDED 1 Freshly distilled or deionized w
14. ld be considered positive for antibodies to HEV VALIDITY Please do not use this kit beyond the expiry date indicated on the kit box and reagent labels LIMITATIONS 1 Non repeatable positive result may occur due to the general biological of the ELISA assays This assay is designed to achieve very high performance characteristics of sensitivity and specificity and the sandwich model minimizes the unspecific reactions due to interference with unknown matters in sample A negative result with anantibody detection test does not preclude the possibility of infection 2 Common sources for mistakes kits beyond the expiry date bad washing procedures contaminated reagents incorrect assay procedure steps insufficient aspiration during washing failure to add samples or reagents equipment timing volumes sample nature and quality 3 The prevalence of the marker will affect the assay s predictive values 4 This is a qualitative assay and the results cannot be use to measure antibodies concentrations 5 Non repeatable positive result may occur due to the general biological of the ELISA assays This assay is designed to achieve very high performance characteristics of sensitivity and specificity and the sandwich model minimizes the unspecific reactions due to interference with unknown matters in sample A negative result with an antibody detection test does not preclude the possibility of infection 6 Common sour
15. s Note read the absorbance within 15 minutes after stopping the reaction INTERPRETATION OF RESULTS AND QUALITY CONTROL Each microplate should be considered separately when calculating and interpreting results of the assay regardless of the number of plates concurrently processed The results are calculated by relating each sample s optical density OD value to the Cut off value C O of the plate If the Cut off reading is based on single filter plate reader the results should be calculated by subtracting the Blank well OD value from the print report values of samples and controls In case the reading is based on Dual filter plate reader do not subtract the Blank well OD from the print report values of samples and controls 1 Calculation of Cut off value C O NC 0 12 NC the mean absorbance value for three negative controls Example 1 Calculation of NC Well No B1 C1 D1 Negative controls OD value 0 02 0 012 0 016 NC 0 016 2 Calculation of Cut off C O 0 016 0 12 0 136 If one of the Negative control values does not meet the Quality control range specifications it should be discarded and the mean value is calculated again using the remaining two values If more than one negative control OD value does not meet the Quality control range specifications the test is invalid and must be repeated 2 Quality control range The test results are valid if the Quality Control criteria are verified It I
16. s recommended that each laboratory must establish appropriate quality control system with quality control material similar to or identical with the patient sample being analyzed 1 The OD value of the Blank well which contains only Chromogens and Stop solution is less than 0 080 at 450 nm 2 The OD value of the Positive control must be equal to or greater than 0 800 at 450 630nm or at 450nm after blanking 3 The OD value of the Negative control must be less than 0 100 at 450 630nm or at 450nm after blanking 3 Interpretations of the results S the individual absorbance OD of each specimen Negative Results S C O lt 1 samples giving absorbance less than the Cut off value are negative for this assay which indicates that no antibodies to hepatitis E virus have been detected with this HEV Ab ELISA kit Positive Results S C O 21 samples giving an absorbance greater than or equal to the Cut off value are considered initially reactive which indicates that antibodies to hepatitis E virus have probably been detected using this HEV Ab ELISA kit Retesting in duplicates of any reactive sample is recommended Repeatedly reactive samples could be considered positive for antibodies to HEV Borderline S C O 0 9 1 1 Samples with absorbance to Cut off ratio between 0 9 and 1 1 are considered borderline and retesting of these samples in duplicates is recommended to confirm the results Repeatedly positive samples cou
17. t the strips should be treated with a sodium hypochlorite solution at a final concentration of 2 5 for 24 hours before liquids are wasted in an appropriate way The concentrated Washing solution should be diluted 1 to 20 before use For one plate mix 50 ml of the concentrate with 950ml of water for a final volume of 1000mI diluted Wash Buffer If less than a whole plate is used prepare the proportional volume of solution STORAGE AND STABILITY The components of the kit will remain stable through the expiration date indicated on the label and package when stored between 2 8 C do not freeze To assure maximum performance of this HEV Ab ELISA kit protect the reagents from contamination with microorganism or chemicals during storage PRECAUTIONS AND SAFETY This kit is intended FOR RESEARCH USE ONLY The ELISA assay is a time and temperature sensitive method To avoid incorrect result strictly follow the test procedure steps and do not modify them 1 Do not exchange reagents from different lots or use reagents from other commercially available kits The components of the kit are precisely matched as to achieve optimal performance during testing 2 Make sure that all reagents are within the validity indicated on the kit box and are of the same lot Never use reagents beyond the expiry date stated on reagents labels or on the kit box 3 CAUTION CRITICAL STEP Allow the reagents and samples to stabilize at room temper
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