Term
Alpha/Beta T Cell Receptors
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Definition
1. All T cells express a TCR
2. 95% express an alpha/beta TCR ( about 5% express a gamma/delta TCR)
3. All TCRs are expressed in association with CD3
4. CD3 transduces signal
5. Alpha/beta TCR recognizes peptide antigen bound to MHC Class I or Class II proteins |
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Term
Major Histocompatibility Complex (MHC) |
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Definition
-The major histocompatibility complex comprises a stretch of tightly linked genes that encode proteins associated with intercellular recognition and antigen presentation to T lymphocytes.
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Term
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Definition
Class I
Alpha Chain
3 External domains
1 Transmembrane
1 Cytoplasmic tail
Encoded in MHC
Beta-2 Microglobulin
1 External domain
No Transmembrane
No Cytoplasmic tail
Not encoded in MHC
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Term
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Definition
Class II
Alpha Chain
2 External domains
1 Transmembrane
1 Cytoplasmic tail
Encoded in MHC
Beta Chain
2 External domains
1 Transmembrane
1 Cytoplasmic tail
Encoded in MHC
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Term
Tissue Distribution and Function of MHC Class I |
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Definition
Class I
Tissue Distribution
All nucleated cells
RBCs in some species (NOT human)
Function
Presentation of antigens to CD8+ T cells
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Term
Tissue Distribution and Function of MHC Class II |
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Definition
Class II
Tissue Distribution
Antigen presenting cells
Macrophages
Dendritic cells
B cells
Thymic Epithelium
Function
Presentation of antigens to CD4+ T cells
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Term
TCR Recognition of MHC-bound peptides
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Definition
-MHC Class I Binds to CD8
-MHC Class II Binds to CD4 |
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Term
Major Histocompatibility Complex Genes |
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Definition
MHC genes are highly polymorphic
Within the human population, there are numerous alleles that can occupy the different HLA Class I and Class II loci.
Advantage: Greater chance of being able to present critical antigens to T cells.
Disadvantage: Odds of HLA match between unrelated individuals is approximately one in a million.
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Term
MHC genes are expressed.......... |
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Definition
MHC genes are expressed co-dominantly
Individual cells express MHC proteins encoded by BOTH maternally- and paternally-derived chromosome
Thus, most nucleated cells express all Class I MHC proteins encoded in the individual’s genome
Antigen presenting cells express all Class I AND Class II MHC proteins encoded in the individual’s genome.
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Term
Antigen Processing Cytosolic Pathogens |
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Definition
- Degraded in = Cytosol
- Peptides bind to = MHC Class I
- Presented to = Effector CD8 T cells
- Effects on Presenting cell = Cell Death |
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Term
Antigen Processing Cross Presentation of Exogenous Antigens |
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Definition
Degraded in = Cytosol
Peptides Bind to = MHC Class I
Presented to = Naive CD8 T Cells
Effects on Presenting Cell=
The presenting cell (Usually a dendritic cell) Activates the CD8 T Cell |
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Term
Antigen Processing Intravesicular Pathogens |
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Definition
Distributed in = Endocytic Vessicles (Low pH)
Peptides Bind to = MHC Class II
Presented to = Effector CD4 T Cells
Effects on Presenting Cell= Activates to Kill Intravesicular pathogens and parasites |
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Term
Antigen Processing Extracellular Pathogens and Toxins |
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Definition
Degraded in = Endocytic Vesicles (Low pH)
Peptides Bind to = MHC Class II
Presented to = Effector CD4 T Cells
Effects on Presenting Cell = Activate B cells to Produce IG to eliminate extracellular pathogen of toxin |
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Term
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Definition
Alpha chain has V, J, and C Regions
Beta chain has V, J, D, and C Regions |
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