Immuno TCR

How many chains make up a T-cell receptor

Two

T-cell receptors have a very long cytoplasmic tail to facilitate direct signaling

False

Regions of the TCR that contact MHC:peptide

Complementarity Determining Loops (CDRs)

TCRs have high affinity for the MHC:peptide complex

False

Complex of six proteins required for TCR signaling

CD3

CD3 complex includes two copies of which protein

Zeta (and Epsilon)

The T in ITAM stands for

Tyrosine-based

CD3 proteins are covalently linked to TCR by disulfide bonds

False

Number of ITAMs on a single Zeta chain

Three

CD8 co-receptors interact with which MHC class

MHC Class I

CD4 co-receptors interact with which MHC class

MHC Class II

CD4 and CD8 are physically bound to the TCR at all times

False

Model describing how TCR and co-receptors are pulled together by MHC

Induced proximity model

Kinase always traveling with CD4 or CD8

LCK

Phosphorylation of ITAM tyrosines provides sites for further signaling

True

T-cell receptor diversity is generated through

VDJ Recombination

TCR chain equivalent to heavy chain with V D J segments

Beta

TCR chain equivalent to light chain with only V and J segments

Alpha

In the Beta chain CDR3 is formed at junction of

V D and J

DD fusion is a unique diversity mechanism in T-cells

True

Enzymes required to initiate TCR gene rearrangement

RAG1 and RAG2

T-cells do not have a secreted version of their receptor

True

Process NOT happening in T-cells

Somatic hypermutation and Class switching

Once a T-cell finishes processing in the thymus its receptor does not change further

True

Two major types of T-cells discussed

CD4 and CD8

Classic T-cells use which two chains

Alpha and Beta

TCR chains considered heavy-like because they contain D segments

Beta and Delta

Alpha and Delta gene loci are on the same chromosome

True

Location of entire Delta locus

In the middle of the Alpha locus

VJ rearrangement for Alpha deletes DNA for Delta

True

T-cell type enriched in barrier tissues like skin and gut

Gamma/Delta T-cells

Alpha/Beta T-cells easier to isolate from mouse spleen than Gamma/Delta

True

Where progenitor cells go to become T-cells after bone marrow

Thymus

Thymus is located above the

Heart

Part of thymus that is darker with higher cell density

Cortex

Lighter inner region of thymus

Medulla

Supporting cells in thymus contacting developing T-cells

Thymic stromal cells

Process where thymus is replaced by fat cells with age

Thymic Involution

T-cell production stops completely at age 10

False

T-cell development and selection take place in bone marrow

False

Molecules providing P and N nucleotides during TCR assembly

Junctional diversity mechanisms

Chain with 23-bp and 12-bp RSSs similar to B-cell light chains

Alpha