Antigen Flashcards
Ag-Ab reaction is __
ALWAYS SPECIFIC
Any molecular structure capable of antibody production
ANTIGEN
No ___ should react with a ___
HEALTHY IMMUNE SYSTEM
NORMAL ANTIGEN
Capacity of immune system to react with foreign/non-self
MAJOR HISTOCOMPATIBILITY COMPLEX (MHC)
Parts of Antigen:
CARRIER PROTEIN
EPITOPE/DETERMINANT
Part of Ag responsible for molecular weight
CARRIER PROTEIN
Part of Ag responsible for specificity
EPITOPE/DETERMINANT
Part of Ag that interacts with Fab portion of Ab
EPITOPE/DETERMINANT
Properties of Antigen:
IA
IMMUNOGENICITY
ANTIGENICITY/SPECIFICITY
Ability of substance to induce specific immune response —> ___
IMMUNOGENICITY
FORMATION OF IMMUNE LYMPHOCYTES/ANTIBODIES
Antibody producing capability of antigen
IMMUNOGENICITY
Factors that Affect Immunogenicity:
FSC
FOREIGNNESS
SIZE
CHEMICAL COMPLEXITY
Level/extent of immune response
FOREIGNNESS
More ___, more immunogenic
FOREIGN
Must be recognized as ___ to elicit immune response
FOREIGN
Antigen Types:
AAHH
AUTOANTIGEN
ALLOANTIGEN
HETEROANTIGEN
HETEROPHILE ANTIGEN
Self
Derived from host
Do not elicit immune response bc “self”
AUTOANTIGEN
When autoantigens elicit immune response
AUTOIMMUNE DISORDER
Derived from other individuals
Elicit immune response
ALLOANTIGEN
Produced from alloantigenic stimulation
Commonly detected in ___ & ___
ALLOANTIBODIES
ANTIBODY SCREENING
IDENTIFICATION
Alloantigens of donors are tested
CROSSMATCHING
Derived from other species
Elicit immune response
HETEROANTIGENS
Heteroantigens that exist in unrelated plants/animals
Either ___ / ___ in structure
HETEROPHILE ANTIGENS
IDENTICAL
CLOSELY RELATED
Graft Types:
AIAH
AUTOGRAFT
ISOGRAFT/SYNGRAFT
ALLOGRAFT
HETEROGRAFT/XENOGRAFT
From individual’s own body
Ex: ___
AUTOGRAFT
SEVERE BURNS
From identical individuals
Ex: ___
ISOGRAFT/SYNGRAFT
TWINS
From non-identical individuals of same species
Ex: ___
ALLOGRAFT
KIDNEY, BLOOD TRANSFUSION
From other species
HETEROGRAFT/XENOGRAFT
SIZE
____ molecule, more immunogenic
LARGER
Number of epitope ___ with size of molecule
INCREASING PROPORTIONALLY
Albumin Molecular size
30,000-60,000 DALTONS
Hemocyanin Molecular size
100,000-MILLION DALTONS
Stable, found in vaccine
ALBUMIN
Highly complex
HEMOCYANIN
___ complex, ___ molecular size
MORE
GREATER
Molecular size to be Immunogenic
> 10,000 DALTONS
<10,000 daltons
Do not elicit immune response
HAPTEN
Overall chemical structure of antigen
CHEMICAL COMPLEXITY
Best & strongest
Peptide linkages = highly stable —> ___ —> higher chance immune cells will recognize
PROTEIN
LONGER CIRCULATION LIFE
Examples of Polysaccharides
ENDOTOXIN, PNEUMOCOCCAL CAPSULE
Surface antigens
Ex: ___
GLYCOPROTEINS
ABO, Rh ANTIGENS
Example of Polypeptide
INSULIN
Least immunogenic bc ___ –> shorter circulation life
NUCLEIC ACIDS, LIPIDS, AMINO ACIDS
EASILY DISSOCIATE/DISINTEGRATE
Ability of antigen to react specifically with the Ab/cell that caused it to be produced
ANTIGENICITY/SPECIFICITY
Incomplete antigen
Not immunogenic by itself, needs ___
HAPTEN
CARRIER PROTEIN
Most common carrier protein of Hapten in circulation
ALBUMIN
Any substance that can induce an immune response
IMMUNOGEN
Not all ___ are ___, but all ___ are ___
ANTIGENS
IMMUNOGENIC
IMMUNOGENS
ANTIGENIC
Special class of immunogen
Causes hypersensitivity reactions
ALLERGEN
Exaggerated immune response damaging/harmful to individual
HYPERSENSITIVITY
Most fatal
High exposure rate –> ___
TYPE 1 / IMMEDIATE HYPERSENSITIVITY REACTION
DEATH
Examples of Hypersensitivity reactions
ASTHMA ATTACK, SYSTEMIC ANAPHYLAXIS
Substances added to immunogen to enhance immune response
ADJUVANTS
Actions of Adjuvants:
PIS
PROLONGS RETENTION TIME OF IMMUNOGEN
INCREASES EFFECTIVE SIZE OF IMMUNOGEN
STIMULATES INFLUX OF MACROPHAGES AND/OR LYMPHOCYTES
Most immunocompetent WBCs
LYMPHOCYTES
Examples of Adjuvants:
LPS (LIPOPOLYSACCHARIDES)
CFA (COMPLETE FREUNDS ADJUVANTS)
ALUMINUM ADJUVANTS
Water in oil emulsion of Mycobacterium butericum / Bordatella pertussis
CFA (COMPLETE FREUNDS ADJUVANTS)
Most commonly used in clinical setting
ALUMINUM ADJUVANTS
Similarity of Affinity & Avidity
BOTH PERTAIN TO STRENGTH OF INTERACTION
Strength of interaction between epitope and antigen combining site of antibody
AFFINITY
Strength of interaction between complex antigens and antibodies
AVIDITY
Difference between Affinity & Avidity
AFFINITY - SIMPLE
AVIDITY - COMMPLEX, SUM TOTAL OF INTERACTIONS, MULTIPLE