Immunology and Pregnancy Flashcards
Why is the immune system relevant?
The fetus is an allograft - is not 100% made of mums DNA and should be rejected like a foreign graft
What are the arms of the immune system?
Innate (recognise danger) and adaptive (recognised non-self)
3 sections - what do they recognise, negative selection, antibody?
What do B cells do?
They recognise soluble antigen and produce antibodies that have antigen specific receptors (BcR).
During development antigen specific receptors that bind to self antigens are killed in negative selection
The antibody is a soluble version of the BCR and bind to pathogens and targets them for killing
What is a T cell receptor and what does it bind?
This is analogous to antigen binding region of an antibody/BcR but can’t bind to soluble antigen directly. Antigen peptides must be presented on MHC.
What is negative selection and positive selection in T cells development?|
Negative selection - any that bind to self antigens are killed (some become Tregs to give autoimmunity)
Positive selection - T cells that won’t bind to self MHC are killed
What do class 1MHC present and to what cell?
intracellular antigens to cytotoxic T lymphocytes (CTL)
What do class 2 MHC present and to what cell?
extracellular antigens to helper T cells
What is MHC class 1 found on?
All nucleated cells
How does class 2 MHC show antigen to T cells?
The alpha and beta chains of the MHC form a tetramer with invariant chain and then they go into the endosome where they are cut by proteases before being shown to CD4 helper T cells
What are the T helper cells?
Th1 TH2 Th17 and Tregs and what they differentiate into depends on singals from the innate immune system
What do TH1 cells do?
These recruit macrophages, are inflammatory but can cause tissue damage/autoimmunity
What can Th2 cells do?
Kill parasites and cause allergies
What do tregs do?
Supress other immune responses and supresses autoimmunity
What are CTL’s?
Induces apoptosis through perforin/granzymes
How do T cells respond to allografts?
They kill them
Why do NK cells kill and not kill cells?
Primed to kill any cell unless told not to by KIR binding on MHC on surface of the cell and preventing killing
what is the placental membrane and what does this mean?
This is the name of the type of placental membrane not like describing
A syncytium which means no cell junctions for maternal immune cells to migrate between and no lymphactics
Does fetal tissue express any MHC 2 or MHC1 and why?
express no MHC2 and some MHC1 (mainly HLA-C) which causes them to escape the CTL response