BIO 340 Study Guide Questions with Verified
Correct Answers
what are the 2 classes of TCRs?
1. α:β
2. γ:δ
what are α:β TCRs?
- standard TCR, the majority of circulation T cells
- called TCR2
what are γ:δ TCRs?
- ~1-5% of T-cells in circulation
- called TCR1
- dont required antigen to be present on MHC molecules
- dont express CD4 or CD8
- can recognize nonpeptide ligands
when does receptor editing occur?
when receptor is nonfunctional or autoreactive; changes antigen specificity
what goes through receptor editing?
- B-cell Igs
- TCRs
what is clonal deletion?
,if B cell cannot create a receptor that is no longer self-reactive it undergoes apoptosis
What are iNKT cells?
distinct population of T cells that express an invariant α:β T cell receptor and several cell surface
molecules also found on NK cells
where can you find iNKT cells?
in human blood
what do iNKT cells recognize?
glycolipid antigens presented by the non-polymorphic MHC class I-life molecule CD1d
what are the 2 types of NK cell receptors?
1. activating NK receptors
2. inhibitory NK receptors
what do activating NK receptors do?
respond to ligands that should not be present on target cell -> trigger cytotoxic activity
what are inhibitory NK receptors?
recognize receptors/ligands that should be present -> restrain NK cell killing
what happens to a normal autologous MHC class I expressing cell?
- inhibitory receptors are engaged
- activating receptors are not engaged
, - no activating ligands are present
- no cell death
what happens to a cell with reduced/lost MHC class I + expression of ligands for activating
NK receptors?
- inhibitory signaling decreases
- activating signaling increases
- NK cells release cytotoxic granules
- target cell is killed
what happens to a cell that expresses MHC class I but aloss has ligands for activating NK
receptors?
outcome depends on relative strength of inhibitory vs activation signaling
what happens to cells lacking both MHC class I and activating ligand?
- may express alternative ligands for inhibitory NK receptors
- possibly ignored by NK cells
what is MHC called in humans?
humal leukocyte antigen (HLA)
what are MHC class II genes named?
- HLA-DQ
- HLA-DP
- HLA-DR
Correct Answers
what are the 2 classes of TCRs?
1. α:β
2. γ:δ
what are α:β TCRs?
- standard TCR, the majority of circulation T cells
- called TCR2
what are γ:δ TCRs?
- ~1-5% of T-cells in circulation
- called TCR1
- dont required antigen to be present on MHC molecules
- dont express CD4 or CD8
- can recognize nonpeptide ligands
when does receptor editing occur?
when receptor is nonfunctional or autoreactive; changes antigen specificity
what goes through receptor editing?
- B-cell Igs
- TCRs
what is clonal deletion?
,if B cell cannot create a receptor that is no longer self-reactive it undergoes apoptosis
What are iNKT cells?
distinct population of T cells that express an invariant α:β T cell receptor and several cell surface
molecules also found on NK cells
where can you find iNKT cells?
in human blood
what do iNKT cells recognize?
glycolipid antigens presented by the non-polymorphic MHC class I-life molecule CD1d
what are the 2 types of NK cell receptors?
1. activating NK receptors
2. inhibitory NK receptors
what do activating NK receptors do?
respond to ligands that should not be present on target cell -> trigger cytotoxic activity
what are inhibitory NK receptors?
recognize receptors/ligands that should be present -> restrain NK cell killing
what happens to a normal autologous MHC class I expressing cell?
- inhibitory receptors are engaged
- activating receptors are not engaged
, - no activating ligands are present
- no cell death
what happens to a cell with reduced/lost MHC class I + expression of ligands for activating
NK receptors?
- inhibitory signaling decreases
- activating signaling increases
- NK cells release cytotoxic granules
- target cell is killed
what happens to a cell that expresses MHC class I but aloss has ligands for activating NK
receptors?
outcome depends on relative strength of inhibitory vs activation signaling
what happens to cells lacking both MHC class I and activating ligand?
- may express alternative ligands for inhibitory NK receptors
- possibly ignored by NK cells
what is MHC called in humans?
humal leukocyte antigen (HLA)
what are MHC class II genes named?
- HLA-DQ
- HLA-DP
- HLA-DR
