Lecture 7 - Naive T Cell Development Flashcards
What is the progression of how an animal protects itself from foreign pathogens
1 - anatomic barrier
2 - complement/antimicrobial proteins
3 - innate immune cells
4 - adaptive immunity
Define each letter in the acronym ART
A - Avoid (anatomic barriers and behavior modification; wound licking)
R - Resist (reduce or eliminate pathogens; fever and innate)
T - Tolerate (enhance tissue’s capacity to resist damage)
What is the job of CD8 T cells
Cytotoxic
MHC I activation
Kill infected, transformed, or tumorous self cells
What is the job of CD4 T cells
helper
MHC II activation
activates or suppresses other immune cells
What is the job of memory or plasma B cells
secrete antibodies
Define: naive lymphocytes
circulating lymphocytes that have not encountered antigens, no functional activity, will differentiate to effector or memory
Where do T cells mature? Where do B cells mature?
thymus; bone marrow
What color do lymphocytes stain on histiology
dark blue
T/F: the variable region of TCR is antigen specific
True
T/F: ALL animals except ruminants and pigs have TCRs with gamma:delta chains
false - most animals have alpha:beta TCR
T cells express _____ while B cells express _____
TCR; BCR
What do the epithelial cells provide for growing cells
growth factors + nutrients
express MHC and Ags to thymocytes
eliminates self Ag-reactive cells
Where do t cells develop in the thymus
cortex
T/F: TCR undergo DNA recombination to create very diverse TCR
True
Summarize the sequential development of cells in the thymus
DN1 - DN2 - DN3 (pre-TCR) - DN4 (proliferation) - DP (CD4, CD8 - TCR) - SP
Postive selection in the cortex
thymocytes that bind moderately/strongly to self MHC survive (become CD4/8 single positive cells)
negative selection in medulla
T cells that bind moderately to self MHC on APCs survive
T cell precursors arrive in the thymus and differentiate for up to one week. Before emigration to the thymus, T - cell precursors reside in the
Bone marrow
T/F: when T cells enter the medulla of the thymus they are mature
False
After 1-2 weeks of maturation in the medulla, thymocytes must exit the thymus to become mature circulating T cells. To do so they up-regulate a certain receptor which allows them to
recognize high concentrations of S1P in the blood
How do T and B cells enter the lymph nodes
via high endothelial venules
the spleen ____ blood-borne pathogens
drains
T/F: lymph nodes are only connected to the lymphatic system
False - connected to the vascular and lymphatic system
Define: Homing
migration of lymphocytes to specific tissue, organ, or site of inflammation
what chemokine does stromal cells secrete for T cell homing
SLC (21)
what chemokine do dendritic cells secrete for T cell homing
MIP (19)
Summarize T cell homing
1 - stromal cells secrete SLC
2 - dendritic cells uptake SLC and migrate to lymph node
3 - dendritic cells secrete MIP which attracts T cells
How does lymphocyte circulation in the pig differ from other animals
moves through only the efferent vein to the bloodstream
Give the component that drives T cell homing stage:
Rolling
L-selectin
Give the component that drives T cell homing stage:
Activation
Chemokine (SLC)
Give the component that drives T cell homing stage:
Adhesion
integrins
Give the component that drives T cell homing stage:
diapedesis
chemokines
What cells express Leukocyte function antigen 1 (LFA-1)
T-cells, neutrophils, and macrophages
what job does LFA-1 have
enable migration of naive and activated T cells and used in attachment to target cells
T/F: selectin addressins are only responsible for tissue-specific homing
True
