12 Differences between antigen and antibody (Antigen vs Antibody)

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Last Updated on July 8, 2020 by Sagar Aryal

Differences between antigen and antibody

Antibodies are produced by the immune system in response to antigens (material perceived as foreign). The antibody response to a particular antigen is highly specific and often involves a physical association between the two molecules. This association is governed by biochemical and molecular forces. The reaction between antigens (Ags) and antibodies (Abs) involves complementary binding sites on the Ab and on the Ag molecules. Some of the differences between antigen and antibody are as follows:

Differences between antigen and antibody

Some of the differences are:

S.N.

Characteristics

Antigen

Antibody

1

Molecule Type

Usually, proteins may also be polysaccharides, lipids or nucleic acids.

Proteins

2

Definition

These are substances that provoke an immune response.

These are Glycoproteins that are secreted by immune cells (plasma cells) in response to a foreign substance (antigen).

3

Effect

Cause disease or allergic reactions.

Protect the system by lysis of antigenic material.

4

Origin

Within the body or externally.

Within the body.

5

Parts

Highly variable with different structural conformations and is usually composed of different epitopes.Composed of three main parts:

-Two light chains

-Two heavy chains

-Four polypeptides

6

PrevalenceExists in all types of cells; mostly found in viruses, bacteria, and fungi.Only present in some types of cells.

7

Synonyms

Immunogens

Immunoglobulins

8

Specific binding site

Epitope

Paratope

9

Complexity

Medium; exists due to random mutations in the cell’s gene.

Very High; Complex chemical that bonds to a very specific Antigen.

10

Source

Usually from a foreign substance (viruses, and bacterial and fungal toxins).

Naturally produced by the body (B lymphocytes or B cells).

11

KindsThere are three basic kinds of antigens (Exogenous, Endogenous, and Autoantigens)

There are five basic kinds of antibodies (IgG, IgM, IgA, IgE, and IgD).

12

ExamplesExogenous antigens: bacteria, viruses, fungi, etc.

Endogenous antigens: Blood group antigens, HLA (Histocompatibility Leukocyte antigens), etc.

Autoantigens: Nucleoproteins, Nucleic acids, etc.

Breast milk, tears, saliva, sweat, and mucus.

Differences between antigen and antibody

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