1S [LEC]: Nature of Antigens and the MHC Flashcards
Antigen capable of stimulating the immune response
Immunogens
Type of antigen that cannot stimulate immune response
Haptens
Haptens are also referred to as ___
Incomplete antigens
Antigen which the antibody will not react
Tolerogens
Any substance that can be recognized by the immune system
Antigen
T/F: All antigens are immunogens
False
T/F: All immunogens are antigens
True
Identify whether thymus dependent/ independent:
Complexed with MHC
Dependent
Identify whether thymus dependent/ independent:
Recognized by T cell
Dependent
Identify whether thymus dependent/ independent:
Produces all Ab classes
Dependent
Identify whether thymus dependent/ independent:
Capable of class switching
Dependent
Identify whether thymus dependent/ independent:
Has high and increased affinity
Dependent
Identify whether thymus dependent/ independent:
Has an immune memory
Dependent
Identify whether thymus dependent/ independent:
Requires B cell
Both
Antibody produced by T cell independent immunogen
IgM
Identify whether thymus dependent/ independent:
Not capable of class switching
Independent
Identify whether thymus dependent/ independent:
Has low and decreased affinity
Independent
Identify whether thymus dependent/ independent:
Has no immune memory
Independent
Minimum size requirement for an antigen to be an immunogen
> 10 000 daltons
A size of ___ is classified as a very good immunogen
> 100 000 daltons
Chemical composition of a good immunogen
Polypeptides
Polysaccharides
Examples of protein antigen that are not that immunogenic
Teflon
Nylon
Some protein antigens can be non-immunogenic due to what reason?
Repetitive sequences/ not too complex
To enhance the immunogenicity of hapten, ___ is used
Carrier proteins/ molecules
Small substances that are non-immunogenic in itself
Haptens
How many binding sites does a hapten have?
1
T/F: A hapten, even in the absence of a carrier molecule, can be recognized by an antibody molecule
True (but will not produce immune response)
Identify whether thymus dependent/ independent:
Involves the hapten binding
Independent
Antigens that induce tolerance
Tolerogen
Antigens that diminish immune response
Tolerogen
Antigen type present in the body; self-antigens
Tolerogen
A small portion of the antigen that is recognized by its receptor
Epitope
The antigenic determinant
Epitope
T/F: It is possible that an antigen has multiple epitopes
True
T/F: An antigen has many epitopes with multiple specificity but has only one binding site
FALSE: An antigen has many epitopes with multiple specificity
Molecular shape or configurations recognized by the B cell
Linear
Conformational
Identify whether it can be recognized by the B cell or T cell:
Antigens that are protein, polysaccharides, and lipids in nature
B cell
Identify whether it can be recognized by the B cell or T cell:
Binds to soluble antigens
B cell
Identify whether it can be recognized by the B cell or T cell:
Recognizes accessible, sequential, or non-sequential epitopes
B cell
Identify whether it can be recognized by the B cell or T cell:
Only recognizes peptide-form antigens
T cell
Identify whether it can be recognized by the B cell or T cell:
Cannot bind with soluble antigens
T cell
Identify whether it can be recognized by the B cell or T cell:
Recognizes internal linear peptides produced by antigen processing only
T cell
T/F: B cells can also recognize peptide-form antigens
True
Identify the category of antigen:
Belong to the host
Autoantigen
Autoantigen is also called as ___
Sequestered antigen
Give an example of an autoantigen
Protein lens of the eyes
Identify the category of antigen:
Does not elicit immune response
Tolerogen
Identify the category of antigen:
From other members of the host’s species
Alloantigen
Identify the category of antigen:
From other species
Heteroantigen
Identify the category of antigen:
Antigens that exist in unrelated plants or animals but are either identical or closely-related in structure so that antibody to one can cross react with antigen of the other
Heterophile antigen
Heterophile antigen is under which category of antigen?
Heteroantigen
Identify the category of antigen:
Forssman antigen
Heterophile antigen
Identify the category of antigen:
Serum sickness
Heterophile antigen
T/F: Agglutinogens are soluble antigens
False (they are insoluble/ particulate)
T/F: Precipitinogens are soluble antigens
True
Antigen that causes a phase change
Precipitinogen
Substance administered with an immunogen that increases and hastens the immune response
Adjuvants
Substance that leads to a more effective immune response
Adjuvants
An adjuvant consisting of mineral oil, emulsifier, and Mycobacteria
[heat-killed Mycobacterium tuberculosis in non-metabolizable oils (paraffin oil and mannide monooleate)]
Freund’s adjuvant
Most approved adjuvant in the US, combined with vaccine used in humans
Alum/ Aluminum salts
Identify the adjuvant:
Used in Influenza vaccines
MF59
Identify the adjuvant:
Contains submicron oil-in-water emulsion
MF59
Identify the adjuvant:
Used in Hepatitis B vaccine
Monophosphoryl lipid (MPL)
Identify the adjuvant:
Contains bacteria-derived immunostimulant
Monophosphoryl lipid (MPL)
Identify the adjuvant:
Used in Hepatitis A and Influenza vaccines
Virosomes
Identify the adjuvant:
Contains spherical vesicles containing viral membrane proteins in the lipid membrane
Virosomes
Discovered as genetic locus that determines acceptance or rejection of tissue grafts exchanged between persons
Major Histocompatibility Complex (MHC)
MHC is discovered by which scientist?
Jean Dausset
Scientist who gave emphasis to MHC restriction
Baruj Benacerraf
Scientist who pioneered the genetic basis of MHC
George Davis Snell
Inheritance pattern of HLA
Co-dominance
Membrane proteins present on APCs that display processed antigens to be recognized by T cells
Major Histocompatibility Complex (MHC)
Major Histocompatibility Complex (MHC) was first studied in what animal?
Mice
Cell surface markers that allow immune cells to distinguish “self” from “non-self”
Human Leukocyte Antigen (HLA)
Main component of HLA
Glycoprotein
MHC is located in which chromosome?
Chromosome 6, short arm
T/F: All nucleated cells possess MHC molecules
True
T/F: All nucleated cells will have the same number of MHC molecules
False
MHC class abundant in APCs
MHC Class II
Three main regions present in Class II MHC
DP, DQ, DR
MHC class not involved in antigen recognition
MHC Class III
MHC class associated with complement
MHC Class III
MHC class involved in immune response
MHC Class I and II
Combination of inherited HLA alleles
Haplotype
Identical HLA only happens in what case/s?
Identical twins
Inbred animals
HLA responsible for the prevention of fetus to be rejected
HLA G (Class I)
HLA genes responsible for the regulation of antigen processing
HLA DM, DN, DO (Class II)
T/F: Only peptides can bind to MHC
True
Immune cell that is MHC-restricted
T cell
T/F: Only proteinaceous antigens are recognized by T cell
True
T/F: Since peptides are made up of amino acids, amino acids can be recognized by T cells
False (only peptides are recognized!)
Identify the class of MHC molecules:
All nucleated cells
Class I
Components of the peptide-binding cleft of the Class I MHC
a1, a2
Components of the peptide-binding cleft of the Class II MHC
a1, B1
Component of the Class I MHC that is not attached to the membrane
B2 Microglobulin (B2M)
Where in the MHC molecule is the peptide-binding cleft seen?
Amino terminal end
The a chain of the MHC Class I molecule is connected by what bond?
Disulfide bonds
The chain embedded in the membrane of the MHC Class I molecule
a-chain (a1, a2, a3)
Identify the class of MHC molecules:
Closed at both ends
Class I
Identify the class of MHC molecules:
8-11 amino acids
Class I
Identify the class of MHC molecules:
Presents endogenous antigen to CD8+ T cells
Class I
Identify the class of MHC molecules:
All nucleated cells
Class I
Identify the class of MHC molecules:
B cells, monocytes, macrophages, dendritic cells, thymic epithelial cells
Class II
Identify the class of MHC molecules:
13-18 amino acids
Class II
Identify the class of MHC molecules:
Presents exogenous antigen to CD4+ T cells
Class II
Component of the MHC Class I molecule where the CD8 binds
a3
Component of the MHC Class II molecule where the CD4 binds
B2
The polymorphic part of the MHC Class I molecule
a1 and a2
The polymorphic part of the MHC Class II molecule
a1 and B1
Function of the CD4 and CD8 in MHC
Coreceptors
Class I MHC molecule/s most important for transplantation
HLA A, B
Most abundant class II MHC molecule
HLA-DR
Least abundant MHC class II molecule
HLA-DP
Enzyme that reduces or trims amino acid sequences so it can fit with the peptide-binding cleft of Class I MHC
Endoplasmic reticulum aminopeptidase 1 (ERAP)
Class I MHC antigens that are not present in the cell surface
HLA E, F
Class II MHC antigen that is important in the loading of peptides into the cleft
HLA-DM
MHC Class II antigen that is important in antigen binding
HLA-DO
MHC class that include complement proteins, TNF, and other proteins
Class III
T/F: The MHC molecule will recognize the type of molecule loaded to its cleft
False (cannot recognize whether self or non-self)
A glycoprotein dimer made up of 2 non-covalently linked to polypeptide
Class I MHC
B2-microglobulin is encoded by a gene in which chromosome?
Chromosome 15
Component of the Class I MHC that stabilizes the folding of a chain
B2M
What antigen type in terms of chemical composition is involved in T cells?
Proteinaceous
Immune cells that have the highest levels of class II MHC molecule
Dendritic cells
Where are MHC molecules produced in the cell?
Rough ER
In MHC class I pathway, this molecule will bind to the a chain to stabilize its folding before b2m binding
Calnexin
In MHC class I pathway, this also binds with the a chain, together with calnexin
ERp57
In MHC class I pathway, these chaperones will help load peptides to the cleft
Tapasin
Calreticulin
The 88-kd membrane-bound molecule in the ER keeping the a chains partially folded while it is waiting to bind with the B2-microglobulin
Calnexin
Also bind to a chain that is still unpaired with B2-microglobulin
ERp57
Molecules that will tag damaged and irregular proteins
Ubiquitin
In MHC class I pathway, the protein will be broken down in which organelle?
Proteasome
In MHC class I pathway, these transporter proteins will guide the peptide to be loaded to the MHC class I molecule
TAP 1, TAP 2
Degraded products of proteasomes from damaged proteins are referred to as ___
Defective ribosomal products (DRIPs)
In MHC class I pathway, the MHC molecule with peptide is transported to the ___
Golgi body
Organelle that has a “stacked cylinder” appearance with complex enzymes the degrades proteins into peptide
Proteasome
Potent activators of T cell
Dendritic cells
In MHC Class II pathway, this is where the internalized bacteria/ pathogen will be stored
Phagosome
In MHC Class II pathway, for the phagosome to be degraded, this should be fused with ___
Lysosome
In MHC Class II pathway, the enzymes in the ___ will break down the protein to be peptides
Lysosome
In MHC Class II pathway, this is the structure found in the binding cleft that serves as a chaperone and stabilizes the structure
Invariant chain
In MHC Class II pathway, this structure prevents binding of other peptides
Invariant chain
In MHC Class II pathway, this structure is a part of the invariant chain left after degradation
Class II-associated invariant-chain peptide (CLIP)
In MHC Class II pathway, this MHC molecule assists in CLIP removal so peptide can bind to the cleft
HLA-DM
In MHC Class II pathway, the loading to the cleft happens in which organelle?
Vesicle
In MHC Class II pathway, this structure serves as a chaperone to direct aB heterodimer to an endosomal acidic protein
Invariant chain
MHC class involved in lymphocyte microtoxicity method
Class I
MHC class involved in mixed lymphocyte reaction
Class II
Give the HLA type:
Graves’ disease
HLA-B8
Give the HLA type:
DM type 1
HLA-B8, HLA-DR3, HLA-DR4
Give the HLA type:
Multiple sclerosis
HLA-DR2, HLA-DR3
Give the HLA type:
Hashimoto Disease
HLA-DR2
Give the HLA type:
Myasthenia gravis
HLA-DR2, HLA-DR3
Give the HLA type:
Sjorgen syndrome
HLA-DR3
Give the HLA type:
Rheumatoid arthritis
HLA-DR4
Give the HLA type:
Pemphigus vulgaris
HLA-DR4
Give the HLA type:
Chronic lymphatic leukemia
HLA-DR5
Give the HLA type:
Kaposi’s sarcoma
HLA-DR5
Give the HLA type:
Ankylosing spondilitis
HLA-B27
Give the HLA type:
Reiter’s syndrome
HLA-B27
Give the HLA type:
Systemic lupus erythematosus (SLE)
HLA-DR2, HLA-DR3
