Difference between Antigen and Antibody

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  1. Difference between Antigen and Antibody
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Difference between Antigen and Antibody

DefinitionAn antigen is any substance that triggers an immune response in the body.An antibody is a blood protein that is produced against a specific antigen.
SynonymsAntigens are also known as immunogens.Antibodies are also known as immunoglobulins.
CorrelationAntigen is the foreign substance that triggers an immune response.Antibody is the glycoprotein produced in response to the antigen.
Chemical CompositionAntigens can be either proteins, carbohydrates, lipids or nucleic acids.Antibodies are glycoproteins.
Specific Binding SiteEpitopes are regions of the antigen where interacts with the antibodiesParatopes are variable regions of an antibody that binds to an epitope.
FunctionTriggers the formation of antibodies.Antibodies protect the body from antigens either by immobilizing the antigen or lysing the pathogen.
TypesThe four types of antigens are exogenous antigens, endogenous antigens, autoantigens, and neoantigens.The four types of antibodies are IgM, IgG, IgE, IgD, and IgA.
EffectAntigens cause allergic reactions or even illnessesProtects against the effects of the antigen either by lysis or immobilization of the particle
OriginsAntigens have origins outside the bodyAntibodies always originate within the body
PartsHighly 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
PrevalenceExists in all types of cells; mostly found in viruses, bacteria, and fungi.Only present in some types of cells.
ComplexityMedium; exists due to random mutations in the cell’s gene.Very High; Complex chemical that bonds to a very specific Antigen.
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.


  • https://microbiologyinfo.com/differences-between-antigen-and-antibody/
  • https://pediaa.com/difference-between-antigen-and-antibody/
  • https://microbenotes.com/differences-between-antigen-and-antibody/
  • https://www.differencebetween.com/difference-between-antigen-and-vs-antibody/
  • https://byjus.com/biology/difference-between-antigen-and-antibody/
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