T cell biology Flashcards
Which multipotent cell creates T cells, B cells, NK cells
Common lymphoid progenitor
Where do T cells go to mature
Thymus
What are the transcription factors that activate T cell genes
Notch1, GATA3
Where does the maturation for T cells start in the thymus
Cortex
In the cortex what is cytokine that is required for early T cell development
IL-7
Where are the largest amount of mature T cells in the thymus
Medulla
What are the stages of T cell maturation, where are these locations
Pro-T (thymus), Pre-T (thymus), Double positive (thymus), Single positive/immature T cell (thymus), naive mature T cell (periphery)
What are the two types of polypeptide chains for the T cell receptor
Alpha Beta TCR, Gamma Sigma TCR
Which of the polypeptide chains of the TCR is least common, what is the percentage,where are they located
Gamma Sigma TCR, 1 to 10%, lungs, skin, gut
T/F:Both alpha beta and gamma sigma TCR bind MHC molecules
False: Gamma sigma TCR donot bind MHC complexs but instead bind phospholipds, phospho-antigens, and heat-shock proteins
What are the functions of gamma sigma TCRs
primarily innate immune response, respond rapidly to pathogens, lack memory response
T/F:Once committed to Alpha Beta the TCR cannot further rearrange to use gamma delta
True
What is the function of alpha beta TCR
Adaptive immune response binds (with assistance of co-receptors) to peptide displayed by MHC on antigen presenting cells, Respond within days, show memory response
What are the small linear fractions that actually interact Alpha Beta TCR
MHC1,MHC2, small antigen peptides
What makes up the TCR complex
TCR, (2)CD3, 2 Zeta chains
What is the function of CD3 and Zeta chains
Signal transduction
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
Pro T cell, decision to become Alpha Beta or Gamma Sigma is made, only the Beta chain of the TCR is expressed
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
Pre T cell, RAG1 and RAG2: trigger alpha rearrangement, alpha chain is expressed
At what stage is the CD4+ AND CD8+
Stage 2 (double positive)
T/F: The TCR complex, CD4+ and CD8+ are all present during Stage 2 (double positive)
True
What occurs during Stage 3
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
What is the end result of Stage 3
Productive TCR complex and CD4+or CD8+/mature single positive T cell
What happens to a mature T cell
leaves medulla and circulates through the lymphatic system
What occurs in positive selection
immature double positive T cells encounter epithelial cells that displays self peptides on MHC1 or MHC2
