T cell activation

Question 1

what happens between the T cell and dendritic cell?

Answer 1

there is cognate interaction as binding occurs

Question 2

On the T cell receptor what does the cytoplasmic tail interact with?

Answer 2

signalling molecules upon recognition

Question 3

what happens when the T cell recognises the antigen / MHC upon recognition ?

Answer 3

T cell and antigen-presenting cell form interaction . The TCR transmits signals and T cell becomes activated.

Question 4

what’s the 3 things that happens once the T cell becomes activated ?

Answer 4

proliferation
effector function
polarisation

Question 5

explain proliferation

Answer 5

As there is huge diversity means that antigen-specific T cells are rare so therefore there activated T cells are ‘useful’ so need to proliferate to generate effective immune response as more are produced. The self reactive lymphocytes are removed and the mature T lymphocyte remains.

Question 6

describe effector functions

Answer 6

Once the T lymphocyte matures it can differentiate into either a

– CD4+ T cells – ‘helper’ function
– CD8+ T cells – ‘killer’ function

Question 7

how do the CD8 T cells carry out their effector functions ?

Answer 7

by killing the infected target cell

Question 8

how does the CD4 T cell carry out their effector function ?

Answer 8

by ‘helping’ the B cells to make antibodies

Question 9

describe polarisation ?

Answer 9

cells can ‘polarize’ into T1 and T2 effector cell types in response to distinct cytokines.

Question 10

what does the Th1 cell secreate ?

Answer 10

IFNγ and TNF and activates this macrophage functions

Question 11

what does Th2 secrete ?

Answer 11

IL-4 , IL-5 and IL-10 and ‘helps’ antibody production from B plasma cell. involved with allergic responses

Question 12

what are the CD86 and CD80 ?

Answer 12

co stimulatory molecules that are produced from the APC.

Question 13

what dictates what cytokines are released ?

Answer 13

the co stimulatory molecules produced from the APC

Question 14

what activates the APC to release the co stimulatory molecules ?

Answer 14

the PAMP’s binding to the PRR’s

Question 15

what happens when Th1 are produced ?

Answer 15

the Th2 production is shut down and vice versa

Question 16

what hapens if this cross communication doesn’t occur ?

Answer 16

you can get allergies or septic shock

Question 17

describe Th1 cells ?

Answer 17

The Th1 cell normally binds to macrophages by IFN-y and this kills intracellular bacteria

Question 18

describe Th2 cells ?

Answer 18

The Th2 cells release cytokines IL 4 , IL 5 which activate bone marrow to produce antibodies. The IL 13 released affects the goblet cells and mucus is released. From these cells eosinophils , mast cells and basophils are produced. Normally associated with Helminth parasites.

Question 19

describe Th17 cells ?

Answer 19

These cells release IL 17 which affects stromal cells to release G-CSF and cytokines. IL 22 is released and this causes antimicrobial peptides. This results in neutrophils being released to break down extracellular bacteria and fungi.

Question 20

describe Tfh cells ?

Answer 20

These are follicles of the T cells that have no MHC. They produce IL 21 , they also activate the B cell and cause IgM ( antibody) to be released. These then cause the production of other antibodies that can target all types of microbes.

Question 21

describe Treg ?

Answer 21

These cells are regulatory, and they calm down the immune response by inhibiting the dendritic cells. Therefore, there is no APC cells activating the cd4+.

Question 22

what is the differentiation of CD4 T cells controlled by ?

Answer 22

their interaction with the antigen presenting cell and the local cytokines.

Question 23

what can result if there is an overactivity of Treg cells ?

Answer 23

lead to no immunity and death

Question 24

describe activation of T cell ?

Answer 24

this is the binding of the MHC , TCR and peptide

Question 25

describe survival of T cell ?

Answer 25

this is when the co stimulatory molecules arrive.

Question 26

describe differentiation of T cells ?

Answer 26

this is when the cytokines interact and effector function

Question 27

why are memory cells important in the use of vaccines ?

Answer 27

they reduce the primary response so that the immune response occurs faster and more efficiently.