Structure Function of TCRs and BCRs, and immunological synapse

Question 1

which parts of the BCR are “highly variable”?

Answer 1

the NH-terminus of H and L chains

Question 2

which parts of the TCR are “highly variable”?

Answer 2

the NH-terminus of V(alpha)-B(beta)

Question 3

Which part of the BCR and TCR has limited variability?

Answer 3

the c region, also cytoplasmic region

Question 4

BCR: what kind of antigens

Answer 4

sugars, lipids, nucleic acids, a.a.’s

all conformations of peptides and linear epitopes

Question 5

TCR: what kind of antigens

Answer 5

only a.a.s in primary conformation, linear sequence

Question 6

BCR: signaling molecules

Answer 6

Ig(alpha)/Ig(beta) subunits

Question 7

TCR: signaling molecules

Answer 7

CD3 and zeta subunits

Question 8

Effector functions of BCR

Answer 8

Fc region of Ab

Question 9

Effector functions of TCR

Answer 9

No effector function

Question 10

3 invatiant domains =

Answer 10

CD3 (epsilon gamma and epsilon delta) and the seta chains

Question 11

what is expressed by the term “resting APC”

Answer 11

that only MHC II is expressed but not costimulatory molecules

Question 12

what is expressed by the term “activated APC”

Answer 12

MHC and costimulatory molecules are expressed

Question 13

what costimulatory molecules do activated APCs express?

Answer 13

B7-1 (CD80), B7-2 (CD86)

Question 14

name 7 molecules required for a T cell to be activated

Answer 14

TCR–MHC interaction+CD4/8+MHC interaction+TCR–CD3 interactions+Zeta(s)–CD3 interactions + CD28–CD80 interactions

Question 15

TCR-APC: Signal 1 only

Answer 15

anergy

Question 16

TCR-APC: Signal 2 only

Answer 16

NO EFFECT on cell

Question 17

TCR-APC: Signal 1+2

Answer 17

TCR-MHC (sig 1)+CD28–CD80 (sig 2)

T cell Activation

Question 18

Costimulation can determine three fates for the T cell

Answer 18

1) Apoptosis (cell death)
2) Anergy (cell inactivation)
3) T cell activation

Question 19

Immunological Synapse

Answer 19

TCR engagement upregulates the expression adhesion molecules (integrins) that hold APC-T cell together

this is called the imm. synapse

Question 20

What molecules pariticpate in the immunological synapse?

Answer 20

TCR, CD4/8, CD3, Zetas, CD28, LFA-1

Question 21

Adhesion, Signal transduction =

Answer 21

CD4/8

Question 22

Antigen recognition =

Answer 22

TCR

Question 23

Signal transduction =

Answer 23

CD3, zetas, CD28 (or CTLA-4, inhibitory)

Question 24

Adhesion

Answer 24

LFA-1

Question 25

gamma/delta T cells: what molecules do they NOT express

Answer 25

CD4/8

Question 26

gamme/delta T cells are activated by with/without APC

Answer 26

w/out via PAMPs

Question 27

gamma/delta T cells store their memory cells where?

Answer 27

they have no memory cells

Question 28

how diverse is the gamma/delta T cell?

Answer 28

limited

Question 29

How many B lymphocytes are produced in the bone marrow every day?

Answer 29

10^9

Question 30

Where are plasma cells located?

Answer 30

largely in lymphoid organs

Question 31

what is the specific marker for B cells?

Answer 31

CD19

Question 32

Surface Ig can be

Answer 32

IgM or IgD

Question 33

what are the components of the BCR complex?

Answer 33

BCR+Ig(alpha)/Ig(gamma)

Question 34

Two mechanisms of B cell activation

Answer 34

Thymus Dependent (protein-Ag, facilitated by helper T cells)

Thymus independent (all other molecules, no need for T cells to help)

Question 35

Thymus dependent activation of B cell: signal 1 and Signal 2

Answer 35

1) Ag binding to receptors
2) Helper Th2 cells deliver CD40 ligand and cytokines
- —> B cell proliferation/differentiation into plasma cells

Question 36

How are plasma cells created?

Answer 36

CD40L from T cells stimulate CD40

Question 37

Thymus independent activation of B cells

Answer 37

B cell activated by carbs, nucleic acids, lipids
this causes cross linking of the BCR

Cross linking —>signal

Question 38

what is the PURPOSE of the immunological synapse?

Answer 38

prevents cytokines from affecting bystanders