Week 6 Flashcards
(34 cards)
2 types of TCR
alpha, beta - 95%
gamma, delta - 5%
Killer T cell is also called
Cytotoxic
In the cortex of thymus there is ____ selection
Positive
In the medulla of thymus there is ____ selection
Negative
Where do T cells develope?
Bone marrow
Cells expressing gamma-delta-TCR arise firstly in
Embryonic development
Is there a selection process in gamma-delta-TCR?
No
What is needed for selection of apha-beta-T cell?
Recognition of self MHC
NOT recognizing self Ag
Positive selection aim
Recognize self MHC+peptide
If weak binding- Apoptosis
AIRE controls?
Expression of self peptides by thymic medullary epithelial cells
Negative selection aim
DIfferentiate self and foreign Ag
How many survive positive selection?
45%
How many survive negative selection?
5%
When do T cell activate?
When they encounter their specific Ag
Dendritic cells migrate via ____ to regional lymph nodes
Afferent lymphatics
Costimularion of T cells happens when
B7 (APC)
CD28 (T cell)
What phosphorylates CD3 ITAM motif?
B7-CD28 interaction
CD4+Kinase
Describe IL2
Autocrine T cell GF
Induces T cell proliferation
IL2-R mutation can cause
SCID (Severe Combined Immuno-Deficiency
Describe the negative costimulation
B7
CTLA4
Down regulates immune response
B7 is also called
CD80
Major site of action of CTLA4
Lymphoid organs
alpha-beta-T memory cells types
T cm (central memory) T em (effector memory)
CD4 can be ___ or ___
Helper
Regulatory
