T cell biology

Question 1

Which multipotent cell creates T cells, B cells, NK cells

Answer 1

Common lymphoid progenitor

Question 2

Where do T cells go to mature

Answer 2

Thymus

Question 3

What are the transcription factors that activate T cell genes

Answer 3

Notch1, GATA3

Question 4

Where does the maturation for T cells start in the thymus

Answer 4

Cortex

Question 5

In the cortex what is cytokine that is required for early T cell development

Answer 5

IL-7

Question 6

Where are the largest amount of mature T cells in the thymus

Answer 6

Medulla

Question 7

What are the stages of T cell maturation, where are these locations

Answer 7

Pro-T (thymus), Pre-T (thymus), Double positive (thymus), Single positive/immature T cell (thymus), naive mature T cell (periphery)

Question 8

What are the two types of polypeptide chains for the T cell receptor

Answer 8

Alpha Beta TCR, Gamma Sigma TCR

Question 9

Which of the polypeptide chains of the TCR is least common, what is the percentage,where are they located

Answer 9

Gamma Sigma TCR, 1 to 10%, lungs, skin, gut

Question 10

T/F:Both alpha beta and gamma sigma TCR bind MHC molecules

Answer 10

False: Gamma sigma TCR donot bind MHC complexs but instead bind phospholipds, phospho-antigens, and heat-shock proteins

Question 11

What are the functions of gamma sigma TCRs

Answer 11

primarily innate immune response, respond rapidly to pathogens, lack memory response

Question 12

T/F:Once committed to Alpha Beta the TCR cannot further rearrange to use gamma delta

Answer 12

True

Question 13

What is the function of alpha beta TCR

Answer 13

Adaptive immune response binds (with assistance of co-receptors) to peptide displayed by MHC on antigen presenting cells, Respond within days, show memory response

Question 14

What are the small linear fractions that actually interact Alpha Beta TCR

Answer 14

MHC1,MHC2, small antigen peptides

Question 15

What makes up the TCR complex

Answer 15

TCR, (2)CD3, 2 Zeta chains

Question 16

What is the function of CD3 and Zeta chains

Answer 16

Signal transduction

Question 17

in Stage 1 (double negative) what is the stage of maturation, is there differentiation into one of the two types of TCR, what part ofthe TCR is present

Answer 17

Pro T cell, decision to become Alpha Beta or Gamma Sigma is made, only the Beta chain of the TCR is expressed

Question 18

In Stage 2 (double positive) what is the stage of maturation, what are the transcription factors active and what do they do, what is other part of the TCR is expressed

Answer 18

Pre T cell, RAG1 and RAG2: trigger alpha rearrangement, alpha chain is expressed

Question 19

At what stage is the CD4+ AND CD8+

Answer 19

Stage 2 (double positive)

Question 20

T/F: The TCR complex, CD4+ and CD8+ are all present during Stage 2 (double positive)

Answer 20

True

Question 21

What occurs during Stage 3

Answer 21

double positive T cells loses one of the CD chains, gains the function of their respective chain, migrate to the medulla while undergoing positive and negative selecton

Question 22

What is the end result of Stage 3

Answer 22

Productive TCR complex and CD4+or CD8+/mature single positive T cell

Question 23

What happens to a mature T cell

Answer 23

leaves medulla and circulates through the lymphatic system

Question 24

What occurs in positive selection

Answer 24

immature double positive T cells encounter epithelial cells that displays self peptides on MHC1 or MHC2

Question 25

T/F: In positive selection low avidity for self peptide MHC complexes promotes T cell survival, T cells that do not recognize self MHC die by apoptosis

Answer 25

True

Question 26

What happens during the transition of positive selection

Answer 26

Double positive T cells that recognize MHC1 will lose CD4 chain and become CD8+ T cells, Double positive T cells that recognize MHC 2 will lose CD8 chain and become CD4+ T cells

Question 27

What is the result of positive selection

Answer 27

Self-MHC restricted Single positive T cells

Question 28

What occurs in negative selection

Answer 28

double positive or single positive cells encounter APCs that display self peptides bound to MHC Class 1 or 2

Question 29

What will trigger apoptosis in negative selection

Answer 29

Strong recognition (high avidity) of self peptide slef MHC complex

Question 30

What is the result of negative selection

Answer 30

Self tolerant T cells

Question 31

What is the most common stage of T cell in the thymus

Answer 31

Double positive

Question 32

What is the majority of T cells

Answer 32

CD4 “helper”

Question 33

What is the function for CD4 T cells

Answer 33

Help B-lymphocytes develop into plasma cells, Help activate CD8+ T cells, Help macrophages effect delayed hypersensitivity reactions

Question 34

CD4 T cell type: TH1

Answer 34

activate cytotoxic T lymphocytes and macrophages, initiate delayed hypersensitivity reaction

Question 35

CD4 T cell type: TH2

Answer 35

activate B lymphocytes to become plasma cells=IgE production, Eosinophil activation

Question 36

CD4 T cell type: TH17

Answer 36

Pro-inflammatory

Question 37

CD4 T cell type: Treg

Answer 37

Suppress activity of T lymphocytes and B lymphocytes=self tolerance

Question 38

T/F: The differences made between CD4 subtypes is by the surface marks

Answer 38

False: Differentiation made is based on signature cytokines secreted

Question 39

What is the function of CD8 T cells

Answer 39

elimination of target cells

Question 40

What does perforin do

Answer 40

Pokes holes in the cell membrane

Question 41

What are the toxic cytokines that are released from CD8+

Answer 41

INF- gamma and INF-alpha