T cells

Question 1

Name the types of T cells

From where do they derive?

Answer 1

5 helper T cells
1 kill T cell
All derive from thymus

Question 2

Cytokines

Answer 2

~Short-range mediators made by any cell, that affect the behavior of the same or another cell
~ eg: IL-1, TNFα, IL-12

Question 3

Lymphokines

Answer 3

~ Short-range mediators made by lymphocytes, which affect the behavior of the same or another cell (subset of cytokines)
~ eg: IL-2, IFNγ, IL-4, IL-5, IL-10

Question 4

Chemokines

Answer 4

~ Small (6-14 kD) short-range mediators made by any cell that primarily cause inflammation
~ eg: MIP-1 to -4, RANTES, CCL28, CXCL16, Eotaxin, IL-8

Question 5

Th1

Answer 5

~ Secrete lymphokines: interferon gamma (IFNy)
~ pro-inflammatory: chemotactic for monocytes
~ IFNy activates monocytes, become classically-activated M1 or angry macrophages which ingest and kill bacteria/foreign invaders
~ macrophages release own cytokines that intensify inflammation including tumor necrosis factor (TNFa) and IL-1
~ risk of damage to local tissues
~ also secretes IL-2 which helps activate killer T cells (CTL)

Question 6

Th17

Answer 6

~ pro-inflammatory: secretes inflammatory lymphokine IL-17

Question 7

Th2

Answer 7

~ produces IL-4, which attracts and activates macrophages
~ alternatively activated macrophages M2
~ healing: debris removal, scar formation, walling off pathogens
~ IL-4 chemotactic for eosinophils (to kill parasites)

Question 8

Tfh - follicular helper T cells

Answer 8

~ activated helper T cells that migrate to follicles of cortex in lymph node, where B cells are abundant
~ help B cells that have recognized antigen to become activated and differentiate into antibody-secreting plasma cells
~ directly contact B cell and stimulate B cells to switch from secreting IgM, to IgG, IgA, or IgE

Question 9

Treg

Answer 9

~ suppress activation and function of all other T cells
~ CD4+/CD25+
~ produce TGFbeta and IL-10

Question 10

Cytotoxic (killer) T cells (CTL)

Answer 10

~ signals target to commit suicide by activating apoptosis that leads to DNA fragmentation and nuclear collapse
~ activated in lymph node after contact w/ antigen bearing dendritic cell
~ for activation also require help from Th1 in form of IL-2

Question 11

Memory Cells

Answer 11

~ after response to antigen, T cell number declines until 5% left
~ will differentiate into effector T cells when re-exposed to antigen