Difference between Antigen and Antibody
| Characteristics | Antigen | Antibody |
| Definition | An 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. |
| Synonyms | Antigens are also known as immunogens. | Antibodies are also known as immunoglobulins. |
| Correlation | Antigen is the foreign substance that triggers an immune response. | Antibody is the glycoprotein produced in response to the antigen. |
| Chemical Composition | Antigens can be either proteins, carbohydrates, lipids or nucleic acids. | Antibodies are glycoproteins. |
| Specific Binding Site | Epitopes are regions of the antigen where interacts with the antibodies | Paratopes are variable regions of an antibody that binds to an epitope. |
| Function | Triggers the formation of antibodies. | Antibodies protect the body from antigens either by immobilizing the antigen or lysing the pathogen. |
| Types | The four types of antigens are exogenous antigens, endogenous antigens, autoantigens, and neoantigens. | The four types of antibodies are IgM, IgG, IgE, IgD, and IgA. |
| Effect | Antigens cause allergic reactions or even illnesses | Protects against the effects of the antigen either by lysis or immobilization of the particle |
| Origins | Antigens have origins outside the body | Antibodies always originate within the body |
| 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 |
| Prevalence | Exists in all types of cells; mostly found in viruses, bacteria, and fungi. | Only present in some types of cells. |
| Complexity | Medium; exists due to random mutations in the cell’s gene. | Very High; Complex chemical that bonds to a very specific Antigen. |
| 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. |
References
- 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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