Antigen
Antigen
Antigen
Lectures outlines
1.Definitions.
2.Classification of antigens.
4.Antigenic epitopes.
5.Adjuvants.
1. Definitions
The word originated from the fact that they can stimulate
antibody generation.
Self vs non-self proteins
• Antigen: any substance capable of provoking an immune
response; molecules not normally present in the body;
non-self
human body
2. Classification of antigens: They can be classified
according to their origin:
I. Exogenous antigens
of an individual as non-self.
IV. Tumor antigens
1) Viral Antigen:
their carcinogens.
b- Alpha fetoprotein:
Massive cytokine
production
Comparison between classical antigen response
and superantigen response
APC
b) LPS (lipopolysaccharide).
nucleic acids).
cosmetics.
3. Factors Influencing Immunogenicity
– Secondary Structure
– Tertiary Structure Conformational determinants
– Quaternary Structure
iv. Physical Form
– Particulate > Soluble
v. Degradability
– Ag processing by Ag Presenting Cells (APC)
vi. Dose.
vii. Route.
– Subcutaneous > Intravenous > Intragastric
viii. Adjuvant
– Substances that enhance an immune response to an Ag
Factors Influencing Immunogenicity
F
e
Types of Epitopes
a. Linear epitopes
continuous and found in polysaccharides as well as protein.
b. Discontinuous epitopes
• Freund’s adjuvant.
Complete Freund’s adjuvant(CFA)
• Liposome.
• Inorganic compound.
• Cytokine.
• Biodegradable nanoparticles.
Mechanisms of adjuvants action
site of injection.
manner.