Differences between antigen and antibody

 

Differences between antigen and antibody

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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	Prevalence	Exists 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	Kinds	There are three basic kinds of antigens (Exogenous, Endogenous, and Autoantigens)	There are five basic kinds of antibodies (IgG, IgM, IgA, IgE, and IgD).
12	Examples	Exogenous 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.