Antigens
From DrugPedia: A Wikipedia for Drug discovery
Antigen (antibody generating) is a substance that prompts the generation of antibodies that can cause an immune response. Antigens can be
- proteins
- polysaccharides
- conjugates of lipids with
* proteins (lipoproteins) and * polysaccharides (glycolipids)
Antigens that enter the body from the environment would include
• inhaled macromolecules (e.g., proteins on cat hairs that can trigger an attack of asthma in susceptible people) • ingested macromolecules (e.g., shellfish proteins that trigger an allergic response in susceptible people) • molecules that are introduced beneath the skin (e.g., on a splinter or in an injected vaccine)
Antigens that are generated within the cells of the body would include
• proteins encoded by the genes of viruses that have infected a cell • aberrant proteins that are encoded by mutant genes; such as mutated genes in cancer cells
Contents |
[edit] Immunogen
Any substance that can elicit an immune response
- All immunogens are antigens
- Not all antigens are immunogens, i.e. haptens
[edit] Immunogenicity of Antigens
[edit] Factors determining immunogenicity
- Foreignness
- Molecular Size
- Chemical Composition
- Degradability
[edit] Factors influencing immunogenicity
- Host genotype
- Dose and route of administration
- Presence of adjuvants
[edit] EPITOPES
- Discrete sites on immunogens recognized by antibodies or T cell receptors
- Macromolecules contain many epitopes with different immunogenicities
- Immunogenicity can vary between individuals and populations.
- Some epitopes are immunodominant
