Lecture 4 Flashcards
What classes of antibody are involved in complement activation?
IgG1, IgG3 & IgM
Differences in functionality are due to the __ of the antibody
Fc region
Th1 cells produce…
IFN-𝛾 and TNFα
Th2 cells produce…
IL-4 and IL-13
Immunosuppressive cytokines produced by Tregs
IL-10 and TGFβ
Tregs are positive for
CD4, CD25 and FoxP3
CD4 is composed of __ domains and projects from the surface to interact with MHC II molecules
Four Ig-like domains (D1-D4)
Structure of CD8
A disulfide-linked heterodimer composed of Ig-like α and β subunits connected to a heavily glycosylated rod-like region that extends from the plasma membrane
The cytoplasmic tails of CD4 & CD8 are associated with which tyrosine kinase?
Lck
TCR activation signals are propagated via the __ , which is made up of __ chains
CD3 co-receptor complex
CD3 𝛾, ε, 𝛿 and ζ chains
Lck initiates signal propagation through __ within the CD3 zeta chain
phosphorylation of ITAMs
Role of CD4 and CD8 on T cell surface
- Act as co-receptors for MHC molecules
- Help stabilise the interaction between TCR and peptide-MHC complex
- Define functional T cell subsets
The 3 signals delivered by APCs to naive T cells
Signal 1: Peptide Ag in MHC II molecule presented to αβ-TCR by DC, CD4 on T cell surface recognises MHC II
Signal 2: Provided by additional surface molecules e.g. CD28 on T cell surface recognises B7 molecules (CD80 or CD86) on APC surface following DC activation via PRR pathways, LFA-1 on T cell binds ICAM-1 on APC to facilitate cell-cell communication
Signal 3: Combination of cytokines produced by APCs & other innate immune cells activate receptors on T cells that have been primed. Cytokine milieu dictates T cell differentiation path
What effect do stable MHC-TCR interactions have on CD3 ε and ζ cytoplasmic tails?
These interactions appear to be able to release the tails from the inner leaflet of the plasma membrane, making their ITAMs accessible to phosphorylation by Lck
When DC interacts with a naïve T cell, which kinase is recruited to the interface between the two cells?
ZAP-70