IMMUNOCHEMICAL TECHNIQUES
IMMUNOCHEMICAL TECHNIQUES:
Immunochemistry is an advanced area of immunology. It deals with the chemical components and chemistry (chemical reactions) of immunological phenomena that is of antibody and antigen. Immunochemical methods are processes utilizing the highly specific affinity of an antibody for its antigen. It detects the distribution of a given protein or antigen in tissues or cells. The methods used for the immunochemical analysis are called Immunochemical techniques.
Characteristics/Advantages of Immunochemical Techniques:
Simple, rapid and robust
Highly sensitive
Easily automated applicable to regular clinical diagnostic laboratories
Does not require extensive and easily destructible sample preparation
Do not require expensive instrumentation
Mostly based on simple photo, fluoro and luminometric detection
Measurements may be either qualitative or quantitative.
METHODS OF ANALYSIS:
All immunochemical methods are based on a highly specific and sensitive reaction between an antigen and an antibody. Antibodies are immunoglobins, belonging to a family of glycoproteins – IgG, IgA, IgD, IgM and IgE. Structurally, antibodies are often visualized as Y-shaped molecules, each containing 4 polypeptides – 2 identical polypeptide units called heavy chains and another 2 called light chains. It has a domain called Fab, the site where it binds to an antigen. The region of an antigen binding to an antibody is called an epitope.
The measure of the strength of the binding is called affinity, and it is usuallyexpressed in terms of the concentration of an antibody-antigen complex measured at equilibrium. It is measured by quantitative precipitin curve (basis for many immunochemical techniques) proposed by Heidelberger and Kendall in 1935.
Quantitative precipitin curve:
It describes the relationship between the antigen concentration and the amount of precipitate for a constant quantity of an antibody.
Immunochemistry is an advanced area of immunology. It deals with the chemical components and chemistry (chemical reactions) of immunological phenomena that is of antibody and antigen. Immunochemical methods are processes utilizing the highly specific affinity of an antibody for its antigen. It detects the distribution of a given protein or antigen in tissues or cells. The methods used for the immunochemical analysis are called Immunochemical techniques.
Characteristics/Advantages of Immunochemical Techniques:
Simple, rapid and robust
Highly sensitive
Easily automated applicable to regular clinical diagnostic laboratories
Does not require extensive and easily destructible sample preparation
Do not require expensive instrumentation
Mostly based on simple photo, fluoro and luminometric detection
Measurements may be either qualitative or quantitative.
METHODS OF ANALYSIS:
All immunochemical methods are based on a highly specific and sensitive reaction between an antigen and an antibody. Antibodies are immunoglobins, belonging to a family of glycoproteins – IgG, IgA, IgD, IgM and IgE. Structurally, antibodies are often visualized as Y-shaped molecules, each containing 4 polypeptides – 2 identical polypeptide units called heavy chains and another 2 called light chains. It has a domain called Fab, the site where it binds to an antigen. The region of an antigen binding to an antibody is called an epitope.
The measure of the strength of the binding is called affinity, and it is usuallyexpressed in terms of the concentration of an antibody-antigen complex measured at equilibrium. It is measured by quantitative precipitin curve (basis for many immunochemical techniques) proposed by Heidelberger and Kendall in 1935.
Quantitative precipitin curve:
It describes the relationship between the antigen concentration and the amount of precipitate for a constant quantity of an antibody.