lecture 35

Question 1

where are the T cells produced

Answer 1

they are produced in the bone marrow

Question 2

where do the naive T cells from the bone marrow travel

Answer 2

travel to the thymus

Question 3

what are the two T cell types

Answer 3

memory and effector T cells

Question 4

describe the memory T cells

Answer 4

Memory T cells can be either CD8 or CD4. these cells reside in the body for a long time years even. Having watched a bodies previous response to an antigen, they can become effector cells for the body next time. As the naïve T cells next time that have TCR for that antigen are much slower responders than the memory cells. This is how the adaptive immune system develops much faster and has memroy for immune responses.

Question 5

describe effector T cells

Answer 5

upon being released from the thymus, they will act as soon as they see the antigen they are made to respond to

Question 6

CD4 cells are the
CD8 are the

Answer 6

CD4 are the helper T cells and CD8 are the cytotoxic cells

Question 7

how do the CD4 cells help to activate the CD8 cells and the B cells

Answer 7

Doing this by secreting growth factors called cytokines which activate the cells.

Question 8

what arm of the adaptive system is the CD4

Answer 8

CD4 is the antibody mediated arm as it activates antibody production

Question 9

what arm of the adaptive system is CD8

Answer 9

CD8 is the cytokine mediated arm as it responds to cytokines from CD4.

Question 10

describe the process of TCR production

Answer 10

When the immature T cell is made in the bone marrow it has its TCR gene in a germline DNA state. Once entering the thymus the T cells are stimulated to rearrange the Gene for TCR. This process is random, and the TCR gene is randomised to make a different TCR for each new T cell. This recombination occurs in the thymus. Once this process has occurred the T cells are then screened to ensure they won’t be autoreactive t cells.

Question 11

TCR is random, this means what

Answer 11

TCR rearranging is random, so it needs to be checked to make sure the TCR made will not react against self tissue

Question 12

what does it mean for a t cell to be naive

Answer 12

its never seen antigen before.

Question 13

what co receptors do each t cell have

Answer 13

CD4 t cells have CD4 co receptors and CD8 have CD8 co receptors

Question 14

CD4 co-receptors help in the binding to what

Answer 14

MHC-2

Question 15

CD8 co-receptors help in the binding to what

Answer 15

MHC-1

Question 16

what is released by the cytotoxic T cells

Answer 16

granzyme and perforin

Question 17

what types of cells can be APC

Answer 17

Dendritic cells, macrophages and monocytes, and B cells

Question 18

what is T cell clonal expansion?

Answer 18

he naive T cell becomes a blast cell that proliferates by clonal expansion and differentiates into memory and effector T cells

Question 19

where does clonal expansion occur

Answer 19

in the lymph nodes