lesson 8 tcells

Question 1

How does the T- recognize antigens on HLA complex (main HLA complex)

Answer 1

With the use of TCR, variable region, antigen specificity

Question 2

types of TCR’s present on T-cells

Answer 2

TcR2alpha beta on d4 and cd8 and TcR1gemmadelta expressed very little

Question 3

Can a t cell have more than one type of TCR?

Answer 3

No, A specific t cell will have a specific TCR and only 1 type with alpha betta chains or gamma delta chains

Question 4

What can the structure of the TCR be compared to

Answer 4

can be compared to a Fab fragment on antibodies, contains two chains each with a variable region and constant region

Question 5

Two different types of t cell receptors and their chain nomenclature

Answer 5

TCR-2 with alpha and beta chains TCR1 with delta and gamma chains

Question 6

Name TCR chain regions

Answer 6

Variable region and constant region

Question 7

TCR genetics, how is variability achieved

Answer 7

in a similar way to antibodies, through somatic recombination during t cell differentiation, different for alpha and for beta

Question 8

Sequences for alpha chain and b chain, which ones recombine ?

Answer 8

alpha has V , j and c sequences where v and j recombine randomly recombine while beta has VDJ and C sequences where VDJ are the ones that recombine

Question 9

How many T-cells graduate from thymus university

Answer 9

about 2%, hard as shit

Question 10

Positive t cell selection, where and how

Answer 10

Through recognition of antigen and self expressed HLA (variable antigens)

Question 11

Negative t cell selection when and how

Answer 11

happens when t cells can recognize self antigen leading to the recognition of peptides that lead to cell death

Question 12

Name all interactions between a t cell and an antigen presenting cell

Answer 12

HLA with TCR and cd4 or 8 bound to HLA, B7 with CD28, Adhesion molecules LAF-1 with ICAM,

Question 13

what are the signals necessary for T cell activation through APC

Answer 13

Antigen recognition, cd4,cd8 recognition of HLA, B7 and cd28 , cd3 intracellular signals

Question 14

What happens if no second signal occurs, what is the second signal

Answer 14

anergy-antigen recognition with no activation

Question 15

CTLA4 receptor

Answer 15

Expressed on t cells AFTER activation, involved in cessation of t cell activity and a return to homeostasis

Question 16

two ways antigen presentation can fail in activating a t cell

Answer 16

either no B7 cd28 interaction or no antigen recognition by TCR

Question 17

What happens after cd4 T-cell activation

Answer 17

Dendritic cell activation in lymph nodes leading to activation of t cells and differentiation of memory t cells

Question 18

What happens after cd8 t cell activation

Answer 18

chemical signaling and release of cytotoxic granules to kill infected or tumor cells

Question 19

Name immunosuppressive drugs and what they suppress

Answer 19

Abatacept and abatacept which are ctla4 antibodies, Cyclosporine and tacrolimus inhibiting signaling from Cd3 and thus IL-2 synthesis p.w, corticoids inhibiting IL-2 synthesis. Chimeric and humanized MoAbs Basilximab and daclizumab as anti CD-25 blocking IL-2 receptor . Rapamycin on M-tor (blocks cell cycle) and finally, Azathioprine and mycophenolate (MFF) inhibiting mitosis.