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. 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 Mycobacterium 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