Immunology 3 ( T Cell Mediated Immunity)

Question 1

Do T cells produce antibodies?

Answer 1

No

Question 2

Do T cells produce secreted TCRs

Answer 2

No

Question 3

What family are TCRs and Immunoglobulins members of?

Answer 3

The immunoglobulin superfamily

Question 4

True are false: the variable domain on each t-cell differs?

Answer 4

True

Question 5

Describe the make up of a T cell receptor.

Answer 5

Alpha chain and beta chain. Constant alpha and variable alpha and constant beta and variable beta

Question 6

How do helper T cells help B cells?

Answer 6

Help them differentiate into Ig secreting plasma cells

Question 7

How do helper T cells help macrophages?

Answer 7

Activates them so they can carry out phagocytosis and killing

Question 8

What at T cells relationship with APCs?

Answer 8

T cells can not interact directly with antigens can only interact with antigens presented on cells (APC)

Question 9

What is the only type of antigen T cells will recognise?

Answer 9

Proteins

Question 10

What allows the antigen peptide to be presented on APCs?

Answer 10

A surface membrane protein called HLA in humans MHC in mammals

Question 11

What is the mhc1 receptor made of?

Answer 11

Alpha 1,2,3 and a beta micro globulin

Question 12

What type of T cells bind to HLA class 1 cells?

Answer 12

Cd8 cytotoxic T cells

Question 13

What is the HLA class ii receptors made of?

Answer 13

Beta 1,2 and alpha 1,2. ( the 1’s are closest to the antigen)

Question 14

What T cells bind to HLA class 2?

Answer 14

Helper T cells

Question 15

What are the helper proteins for HLA-t cells interactions?

Answer 15

Cd4 (helper) and cd8 (cytotoxic)

Question 16

What is cd8 made of?

Answer 16

Two polypeptide chains that bind to alpha 3 of the HLA class 1

Question 17

What is cd4 made of?

Answer 17

It is a single polypeptide but with 4 immunoglobulin like domains ( part of superfamily) that bind to the side of the beta 2 domain of HLA 2

Question 18

What are protein antigens in the cytoplasm degraded in?

Answer 18

A complex called a proteosome

Question 19

How are peptides transferred the proteosome to the endoplasmic reticulum?

Answer 19

Via peptide transporter proteins.

Question 20

What length are the processed peptides?

Answer 20

8 or 9 aa

Question 21

Where do the processed peptides meet the newly synthesised HLA 1?

Answer 21

In smooth endoplasmic reticulum via peptide transporter gateways. Once complex they move to the surface

Question 22

What happens after enocytosis of exogenous particles?

Answer 22

Internalised into a vacuole. Enzymes entering the vacuole degrade the antigen.newly synthesised HLA 2 is transported to vacuoles and complexed with antigen peptide aa

Question 23

What processing do infected cells do?

Answer 23

HLA class 1 processing

Question 24

What do B cells that have taken in bound antigen do?

Answer 24

HLA type ii processing- helper T cell comes and turns B cell into a plasma cell

Question 25

Can most cells process HLA 1 and 2?

Answer 25

Most cells type 1 | Mostly immune cells type 2

Question 26

What types of cells express high levels of type HLA type 1 and 2?

Answer 26

Dendritic cells

Question 27

What are cytokines?

Answer 27

Secreted proteins that regulate cellular activity

Question 28

How do cytokines work?

Answer 28

By binding to cell surface receptors and triggering intercellular signalling pathways

Question 29

State the 5 types of cytokines

Answer 29

1) interleukins 2) tumour necrosis factor (TNF) 3) interferons 4) colony stimulating factor 5) chemokines

Question 30

What to TH1 cells do?

Answer 30

Drive cell mediated immunity through t-cells and macrophages

Question 31

What IL does Th1 produce and what does it do?

Answer 31

IL-2 activates proliferation of T cells.

Question 32

What interferon do th1 cells mostly produce and what does it do?

Answer 32

INF-gamma main function is to activate macrophages to activate and stimulate phagocytic digestive functions

Question 33

What is the main objective of th2 cells?

Answer 33

Activation of B cells and production of antibodies (not to activate T cells and macrophages)

Question 34

Do th1 and th2 work together?

Answer 34

No, they inhibit each others activity through their cytokines

Question 35

What are th0 cells?

Answer 35

When Th cells leave the thymus they are not committed to being Th1 or Th2.

Question 36

What determines if a th0 call become Th1 or Th2?

Answer 36

The cytokine signals it receives at time of activation with an antigen - polarisation!!!

Question 37

What cytokine produces th1 and th2 cells?

Answer 37

IL-12 produces th1 | il-4 produces th2

Question 38

In lymph nodes where do T cells primarily locate?

Answer 38

The paracortex

Question 39

Where do the B cells usually locate?

Answer 39

In the follicles

Question 40

In the lymph nodes there do t-cells and dendritic cells usually interact?

Answer 40

Paracortex

Question 41

Where do helper T cells and B cells interact?

Answer 41

At the edge of the follicles

Question 42

In the paracortex what activates T and B cells??

Answer 42

Activation of antigen specific T cells by dendritic cells and activation of antigen specific B cells by T cells

Question 43

How long does it take B cells to mature in the germinal centre?

Answer 43

3-5 days

Question 44

What 4 steps are involved in maturation of a instead B cells?

Answer 44

1) division - increases with size of response 2) antigenic selection- increases affinity of response- bad B cells destroyed 3) class switching- increases effector functions 4) formation of plasma cells and memory cells

Question 45

Do all plasma cells go back to site of infection?

Answer 45

No, some go to bone marrow and produce antibodies from there