Immunogen Antigen (Ag)

Immunogen

• Immunogen

• Antigen (Ag)

• Hapten

• Epitope or Antigenic Determinant

• Antibody (Ab)

Foreignness

• Foreignness

• Size

Foreigness

• Foreigness

• Size

• Chemical Composition

• Physical Form

• Particulate > Soluble
• Denatured > Native

Foreigness

• Foreigness

• Size

• Chemical Composition

• Physical Form

• Degradability

• Ag processing by Ag Presenting Cells (APC)

Genetics

• Genetics

• Species
• Individual
• Responders vs Non-responders

• Age

Dose

• Dose

• Route

• Subcutaneous > Intravenous > Intragastric

• Adjuvant

• Substances that enhance an immune response to an Ag

Proteins

• Proteins

• Polysaccharides

• Nucleic Acids

• Lipids

• Some glycolipids and phosopholipids can be immunogenic for T cells and illicit a cell mediated immune response

Polysaccharides

• Polysaccharides

Proteins

• Proteins

Definition

• Definition

Composition

• Composition

• Proteins, polysaccharides, nucleic acids, haptens
• Sequence (linear) determinants
• Conformational determinants

• Size

• 4-8 residues

Composition

• Composition

• Size

• Number

• Limited (immunodominant epitopes)
• Located on the external surfaces of the Ag

Composition

• Composition

• Proteins (some lipids)
• Sequence determinants
• Processed
• MHC presentation (lipid presentation by MHC-like CD1)

• Size

• 8 -15 residues

• Number

• Limited to those that can bind to MHC

Definition

• Definition

• Examples

• Staphylococcal enterotoxins
• Staphylococcal toxic shock toxin
• Staphylococcal exfoliating toxin
• Streptococcal pyrogenic exotoxins

Adaptive Immune System – Discrete Determinants

• Adaptive Immune System – Discrete Determinants

• Reacts with a specific pathogen

• Innate Immune System – Broad Molecular Patterns

• Reacts with a variety of pathogens

PAMPs – Pathogen Associated Molecular Patterns

• PAMPs – Pathogen Associated Molecular Patterns

• PRRs – Pattern Recognition Receptors