ELISA

Enzyme linked immune sorbent assay . (Diagnostic tool)

1. DAVANGERE UNIVERSITY DEPARTMENT OF MICROBIOLOGY SEMINAR ON THE TOPIC: ELISA.

2. CONTENTS INTRODUCTION PRINCIPLE TYPES OF ELISA APPLICATIONS ADVANTAGES DISADVANTAGES SUMMARY CONCLUSION REFERENCE

3. INTRODUCTION Enzyme linked immunosorbent assay is a solid phase assay which involves binding of either antibodies or antigen to the polystyrene surface of the wells of microtitre plate. The term ELISA was first invented by Eva engvall and Peter Perlman in 1971. ELISA is named because the technique involves the use of an immunosorbent material specific for the components of the reaction antigen or antibody.

4. BASIC PRINCIPLE OF ELISA The principal based on the formation of antigen and antibody complex, which is detected by chromogenic detection using conjugated secondary antibody, the conjugated enzyme acts on a specific substrate called chromogenic substrate and generate coloured reaction product.

5. DIFFERENT ANTIGENS

6. TYPES OF ELISA 1.DIRECT ELISA 2.INDIRECT ELISA 3.SANDWICH ELISA 4.COMPETATIVE ELISA

7. 1.DIRECT ELISA

8. 2.INDIRECT ELISA

9. 3.SANDWICH ELISA

10. 4.COMPETATIVE ELISA

11. APPLICATIONS OF ELISA Qualitative and quantitative analysis of ag and ab. Detection of HIV antibodies in blood samples , drugs and antibiotics. Diagnostic tool in medicine and plant pathology. It has also found in food industry in detecting potential food allergens. Used in detection of M ycobacterium antibodies in tuberculosis.

12. ADVANTAGES OF ELISA Reagents are relatively cheap and have a long shelf life. ELISA is highly specific and sensetive. No radiation azards accure during labelling or disposal of waste. Easy to perform and quick procedures. Equipment can be in expensive and widely available. ELISA can be used to a variety of infections.

13. DISADVANTAGES OF ELISA Measurements of enzyme activity can be more complex than measurement of activity of some type of radioisotopes. Enzyme activity may be affected by plasma constituents. ELISA kits are commercially available but not cheap. Very specific to a perticular antigen ,won't recognise any other antigen.

14. SUMMARY ELISA formation of Ag -Ab complex is identified by linking the antibodies to an Enzyme addition of chromogenic substrate will result in colour development which can be read by ELISA plate reader. ELISA is usually done by 96 well microtitre plate suitable for automation.

15. CONCLUSION ELISA is a novel technique useful in detection of (qualitative and quantitative) an antigen or antibody present in sample, Chromogenic . detection method used in ELISA is convenient and sensetive for any assay and it's hazard life.

16. REFERENCE David male and Jonathan brostoff , Immunology, 8th Edn, published by Dianne zark , International Pvt Ltd,Pp-455 I Kannan, Immunology (2007) published by MJP publisher, Chennai Pp-541 Kenneth Murphy and Casey weaver, Immunology 9th Edn, Published by Garland science Taylor and Francis group, New York, Pp-855 Sudha Gangal and Shubhangi sontakke, Immunology, published by universities press Pvt Ltd, India Pp-517