Flashcards in Lecture 15 Thrush Deck (19):
Difference between effector cells and naive cells
Naive: require CD:28- B7 for activation because it doesnt react wih TCR cells as well; CD45RA; low cell adhesion molecules (CD2 and LFA-1)
Effector cells: don't require CD28:B7 for activation; high cell adhesion and use CD45RO
CD4 T cells and subsets
Th (helper) cells produce cytokines to regulate the immune response (Th1 and Th2)
Tdth (delayed type hypersensitive) cells produce cytokines to stimulate an inflammatory response (Th1)
Tregs - regulatory/suppressive T cells; autoimmunity
Th17 - role in inflammation and autoimmunity
Th9 - promotes survival of Tregs
Th22 - helps control commensal bacteria, anti-inflammatory
CD8 t cells subsets
Tc (cytotoxic) cells produce cytokines that kill target cells
Ts (suppressor) cells produce cytokines to turn off the immune response (?)
CTLs: cell-mediated cytotoxic activities of the immune system and their role in host defense
important in eliminating altered self cells ( virally infected, tumor, and foreign graft)
best at destroying intracellular microbes
are CD8+ T cells that recognize their antigen in association with the MHC class I molecules.
How do CTL-P become activated to become CTL?
TCR : Ag/MHC class I interaction (with CD8)
CD28 : B7
IL2R interaction with IL-2 (from Th1 cell)
Which effector molecules do the CTLs produce
perforin: pore forming
granzymes: apoptosis and produces DNAses
Fas (on target cell) and FasL (on CTL): apoptosis
Binding of Fas and TNF alpha causes?
direct killing of tumor cells
NK: cell-mediated cytotoxic activities of the immune system and their role in host defense
No specific antigen recognition
Active before CTLS
Produces cytokines that can increase macrophages activity
produces perforin and granu.
How do NK recognize target?
recgnize altered self cells
What are the 2 NK receptors
What can serve as an inhibitory signal for NK?
MHC class 1
What can bind to KAR?
cellular stress proteins, including MICA and MICB (are expressed by infected cells to help in actvating NK)
NKT: cell-mediated cytotoxic activities of the immune system and their role in host defense
hybrid between T cells and NK cells
no memory cell
produces IFNg and IL-4
recognize lipids when presented with CD1 molecules
What type of TCRS do NKT cells have?
invariant; very limited diversity
ADCC cell-mediated cytotoxic activities of the immune system and their role in host defense
where does the ADCC antibody and antigen bind?
which cells express FcR
Nk cells, neutrophils, macrophages, eosinophils,
how do ADCC cause cell death?
by releasing granules
can release TNF which can relases perforins and gran.