why only elisa

8/13/2019 Why Only ELISA

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ELISA is defined as

an immunologicaltest that uses

enzyme linked antiglobulin& substrate

bound to an inert surface.

Assay-A quantitative or qualitative test of a substance (especially an ore or a drug) to determine its components; frequently

used to test for the presence or concentration of infectious agents or antibodies etc.


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ELISAThe most important Serological Test

ELISA is a Serological Testwhich is used for either detection of

Ag or Ab.

A reaction is said to be Serological; when Ag-Ab reactions are

carried out in-vitro.

This is aSerological Test.

See the in-vitro

Ag-Ab reaction

being carried out.

This is ELISA plate.

See the 96 walls on

the plate with

12X8 arrang ement


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In these kind of reactions , an absorbing materialspecific

for one of the components i. e. Ag or Ab which are used.

ELISA is a sensitive laboratory method used to detect the

presence of antigens (Ag) or antibodies (Ab) with

a wide variety of biological samples.

ELISA is many times referred as Solid-Phase Immuosorbent

Assay (SPIA) by some professionals due to the fact thatAg or Ab are coated to solid phase.

Why ELISA is so important??????


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Ag or Ab is first coated to TT wall. To this respective Ab or Ag

Is added. To it then enzyme labeled molecule is added. When

substrate is added ; if reaction is positive then colour reaction

is quickly seen.

This is the generalized principle applied in all kinds of ELISA

Tests.


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This is also called as SANDWICH ELISA.The samples that are added are sandwiched in the layers of Ag & Ig

so it is called so.


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ELISA FOR DETECTION OF Ag IN FECES

Ab

EnzymeAg

Secondary AbColour on adding substrate

1.Microassay plate coated with Ab.

2.Ag collected in sample gets coated over Ab.

3.Adding Enzyme labelled Ab ; forming complex.

4.Adding substrate.

5.This forms coloured substrate i.e. test is positive. Substratesplits & colouration is seen.

6.If test is negative, no coloured substrate is formed.


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ELISA FOR DETECTION OF Ab IN SERUM

Colour on adding substrate

Ag

Ab

Ig-Ab with Enzyme

1.Microassay plate coated with Ag

2.Ab in collected sample gets coated over Ag previously

present on micro assay.

3.Adding enzyme labelled Ag (here it may be IgG)4.Adding substrate.

5.This forms coloured substrate indicating positive test.


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Interpreting the result.

Positive Negative(Green colour is seen) (No colour is seen)

l f


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Closer view of ELISA PLATE

NEGATIVE POSITIVEINTERMEDIATE


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APPLICATIONS OF ELISA 11 ELISA is used in detection of FPT.

FPT is Failure of Passive Transport.

FPT is failure of intestinal absorptionof IgGfrom colostrumwhich is required for protection of young one against enteric diseases.

Especially Dipstick ELISAis used here.

2 ELISA is a test used to detect and identify antiviral Ab of wide variety.Here Indirect ELISAis used. This is the simplest techniqueavailable

in commercialmarket.


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3 ELISA is also used in detection of food allergies.No doubt this of limited usefulness.

4 ELISA is also used for detection ofAutoimmune Thyroiditis.

ELISA is used here to detect Ab against thyroid microsomalor colloid Ag.

5 ELISA is used to detect FeLV viremia.

Here , whole blood sample is used.

An alternative technique is the use of salivafor test.

Even tearsare also used.

Of or relating to microsomes

Feline Leukemia Virus

APPLICATIONS OF ELISA 2

A tiny granule in the cytoplasm that is where

protein synthesis takes place under the direction of mRNA


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Why only ELISA???

1. ELISA makes us enable to test widest variety of biological

samplesto test at higher level of accuracy.

2. ELISA is safestas there is no radioactive material involved as in case of

radioactive assays which were used prior to ELISA at larger scale.

3. Recent developmentsin field of Applied Serology makes us to carry out

tests at commercial levelas well.

why only elisa

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