Antigens: types and features

Principles of antigen recognition by T and B cells

Antigen Presenting Cells

ANTIGENS

DEFINITIONS

Antigen

Immunogen

Hapten

Carrier

Epitope or antigenic determinant

ANTIGEN

Molecule that binds antibody or T cell receptor

IMUNOGEN

antigen that induce immune response

IMMUNOGENICITY

Depends on

characteristics of the immunogene

biological system

route of administration

IMUNOGENICITY characteristics of the immunogene

Phylogenetic distance

Molecular size

Chemical composition and heterogeneity

proteins > carbohydrates, lipides, nucleic acids

Physical appearance

particulated > soluble

denatured > native

IMUNOGENICITY characteristics of the biological system

Genetic bacground

– species

– individual

Age

IMUNOGENICITY administration of the antigen

amount

optimal

route

subcutaneous > intravenous > peroral

adjuvant

substancee that stimulates immune

response to the antigen

HAPTEN

small molecule that can not elicit an immune response by itself. It can elicit an immune response only when attached to a large molecule – carrier.

CARRIER

Macromolecule that enables induction of immune response directed to the attached hapten.

ANTIGENIC DETERIMINANTE or EPITOPE

Part of the antigen that binds specific antibody or T-cell receptor

Antigenic determinantes of the proteins

linear

conformational

aminoacidlinear determinant

conformational determinante

Principles of antigen recognition by T- and B-lymphocytes

Antigens recognized by B-lymphocytes are

Proteins (linear and conformational determinants), carbohydrates, nucleic acids etc.

Native and processed

Soluble and membrane

Antigens recognized by T-lymphocytes are

Peptides

Linear determinants

On the cell membrane within groove of self MHC molecule

ANTIGEN-PRESENTING CELLS

Figure 8-14

Ralph Steinman

Dendritc cells

Nobel prize for medicine 2011