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40 Cards in this Set
- Front
- Back
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2 features of a 'good' AG
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Large size
Complex |
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Epitope
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Portion of an AG that is 'recognized' by an AG receptor
Epitopes represent only a portion of the AG itself |
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Dose and route of administration are important due to...?
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Ability of an AG to induce an adaptive immune response
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Affinity
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Describes the strength of the binding forces between AG and AB
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Cross reactivity
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AG receptors may recognize more than one AG
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What causes cross reactivity?
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Presence of similar epitopes on different antigens
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Most frequent source of cross reactivity
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AGs of related organisms
(can also occur between totally unrelated AGs) |
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What happens at very high doses of AGs?
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Immune paralysis
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What is the receptor for B-lymphocytes?
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Membrane form of AB or Ig
AKA B-Cell Receptor (BCR) |
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What is the receptor of T-lymphocytes?
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TCR
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Two classes of TCRs
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TCRαβ
TCRγδ |
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What makes TCRαβ different from TCRγδ?
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Different peptide chains that were encoded on different chromosomes
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Two different regions of peptide chains
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Constant
Variable |
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What is the constant region?
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Similar or identical for all receptors
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What is the variable region?
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Unique to each receptor
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Which region of the peptide chain binds to AGs?
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Variable
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Three gene segments that encode for the variable region of a peptide chain.
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(V)ariable
(D)iversity (J)oining |
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Which species have a single functional gene, but several pseudogenes?
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Rabbits
Chickens |
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What species have both chromosomal rearrangement and gene conversion?
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Sheep
Cattle Pigs |
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Inherited immunodeficiency in Arabian foals
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Foals can't synthesize AG receptors and completely lack T and B lymphocytes
Inability to splice chromosomes together following strand breaks |
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Which receptor does not bind directly to AGs?
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TCRs
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What presents TCRs with AGs?
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MHC
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How do MHC molecules function?
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Transport IC AGs to surface of cell where TCR can 'see' it
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Two types of MHC
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Class I
Class II |
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What cells are Class I MHCs expressed by?
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All nucleated cells
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What cells are Class II MHCs expressed by?
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Dendritic cells
Macrophages B lymphocytes |
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What do Class I MHCs present AGs to?
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CD8 T lymphocytes
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What do Class II MHCs present AGs to?
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CD4 T lymphocytes
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What AGs do Class I MHC present?
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Viral AGs
IC parasites |
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What AGs do Class II MHC present?
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EC parasites
EC phase of IC parasites |
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Where are Class I MHCs synthesized?
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IC
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Where are Class II MHCs synthesized?
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EC and internalized
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What is the most important dendritic cell?
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Myeloid
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Two functions of sentinel cells
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Capture AGs
Activate innate immune mechanisms |
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4 locations of myeloid dendritic cells
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Most tissues
Lymph nodes Spleen Thymus |
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2 functions of myeloid dendritic cells
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Capture and process AGs
Present AG + MHC to T lymphocytes |
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Three ways that immature myeloid dendritic cells capture AGs
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Phagocytosis
Pinocytosis Receptor mediated endocytosis |
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How do myeloid DCs mature (become activated)?
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Coming into contact with:
PAMPs DAMPs Inflammatory cytokines |
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Anergy
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Immature myeloid DC lacks surface molecules to deliver activation signals --> presents an AG to a T lymphocyte --> no immune response --> T lymphocyte deactivates
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Mature myeloid DCs synthesize surface molecules --> deliver activation signals to T cells --> initiate immune response
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Mature myeloid DCs synthesize surface molecules --> deliver activation signals to T cells --> initiate immune response
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