Cell Mediated (I) Flashcards
What is cell mediated immunity called
Adaptive transfer of immunity via cells not serum
Which types of antigens does T cell recognise
Cell associated
Antigenic peptides on MHC
What are the 2 ways T cells work
Cytotoxic to kill viruses
Th to modulate macrophages and B cells
Explain the 4 domains of a TCR on T cells
V alpha V beta
C alpha C beta
2 chains
How are alpha and beta in Tcr linked
Disulfide bond
Explain the structure of MHC class I
Alpha 3 domains (A1,2,3)
1 beta2 microglobulin
1 transmembrane domain
What makes up the MHC 1 peptide binding cleft
Alpha 1 and 2
How is MHC II different to MHC I
1 alpha chain (A1,2)
1 beta chain (B1,2)
2 transmembrane domains
What makes up MHC II binding cleft
A 1, B 1
Which cell types are MHC 1 on compared to MHC 2
MHC 1- on all cell types
MHC 2- APC (b cells, dendritic, macrophages)
Which type of antigen do MHC 2 on apc act on
Extracellular (not made by own cell)
How is extracellular antigen taken up and presented by MHC 2 on apc cells
Into vesicles via endocytosis
Fusion with endosome causes acidification
Professes cleave antigen into peptides
Fragmented peptide vesicles fuses with vesicles with MHC II in them
What happens when dendritic cells engulf extracellular pathogens then present them on their MHC 2
Go to the lymphatic system into lymph nodes and causes activation of T cells
Which infections do MHC 1 take care of
Intracellular pathogens
What do MHC 1 with intracellular pathogens/ endogenous antigens bind to
CD8 cytotoxic receptors
How do CD8 kill intracellular pathogens from MHC 1 recognition
Granzymes and perforin
Apoptosis of infected cell
Which MHC interaction causes autoimmune response in diabetes to kill B cells
MHC 1 and CD8
CD8 causes apoptosis of B cells in pancreas
How do CD4 Th cells mediate other cells
Cytokines
What do Th cells leave thymus as and when do they differentiate into 5 types
Th 0
Differentiate when come into contact at lymphatic organs via MHC II
What do TH1 do (type 1 response)
Bind to MHC II on macrophages
Stimulates macrophages and phagocytosis/ inflammation
Which cytokine is released by th 1 to stimulate NK and macrophages and more th1 production
IFN - y
What is Th2 cells for
Kill EC pathogens by attracting eosinophils, mast cell stimulation (b cells activated to produce igE)
What is main cytokine in type 2 response which allows class switching to IgE to activate mast cells / basophils
IL 4
Does IL 4 also stimulate th2 production
Yes
Which Th cells release IL 17 when they recognise MHC II
Th17
What is the action of IL 17 release by Th17
Acts on Stroma cells to secrete chemokines (attract neutrophils for inflammation)
Acts on epithelial cells to release AMPs
What do TFh cells release (follicular)
IL 21
What does IL 21 do by tfh release when MHC II detected
Stimulate differentiation of B cells, class switching and antibody release from plasma cells
Which Th cell is involved in type 1 and 2 response
Tfh
What does T Reg do
Prevents autoimmunity or stimulation of T cells via MHC II
Give example of cytokines released by t reg to stop immunity
TGF, IL 10
