Immune Regulation of Pregnancy Flashcards
(26 cards)
what characteristics do T/B cells need before leaving maturation site?
self tolerance and immunocompetence
compare CD4 and CD8 T cells
CD4: T helper cells, redirect innate and adaptive immune system to fight off specific pathogens
CD8: T killer cells, cytotoxic
describe the processes T cells must go through to ensure they are immunocomp and self-tolerant
positive selection: recognition of self MHC within first few days or they will be deleted
negative selection: surviving T cells go through negative selection, if peptide on APC is own = apoptosis, if it is harmful = self-tolerance
what will likely occur is negative selection process fails?
autoimmune disorder
compare classes of Th cells
TH1: promotes formation of cytotoxic T cells, stimulate inflammation
TH2: stimulate inflammation, react to worms and allergies
describe T reg cells
regulate immune response, prevent autoimmune reactions, important in preg
describe classes of MHC
MHC1 on all cells: HLA-A and HLA-B
MHC2 on immune cells eg APCs
compare men and women response to pathogens
women mount a more robust immune response than men with lower viral load needed to initiate, pregnancy hormones change this where high viral load will not cause symptoms/response
describe effects of prog and est on immune system
prog = dampens
est= normal levels stimulates but higher levels dampens
describe progesterone effects on immune system
anti-inflammatory, downregulates innate immune response of macrophages, dendritic cells, changes T cell type from TH1 to TH2, reduces action Tk cells, increases T regs and UNk cells
describe est effect on immune system
est normally counters prog effects on immune system, tries to switch back to TH1, when est rises= dampening affect, reduce APCs
how does prog usually stim TH2
producing Tregs
describe ovulation effect on immune system
inflammatory event (rupture of follicle) caused by recruitment of immune cells
describe uterus in relation to immune system
specialised Nk cells in uterus, Nk cells normally kill anything without MHC therefore have to be regulated to tolerate fetus
describe inflam stages of pregnancy
stage 1: proinflam linked with implantation and placentation (T1)
stage 2: anti inflam (T2)
Stage 3: pro inflam for initiation or labour
timing is important for healthy pregnancy
describe T reg main function in preg
tell cytotoxic T and B cells to pause allowing tolerance of blastocyst = dampened immune response stim by prog, allows sperm antigens to be ignored
describe uNK cells in preg
normally kill cells without self antigens, uterine NK responsive to both est and prog, allow spiral arteries and decidua to form, generally pro inflam= destroy some uterus for spiral arteries, need balance of anti inflam to tolerate baby
describe balance bw pro and anti inflam uNK cells and MHCs
looking for absence of self antigens, if similar MHC class detected it will promote immune tolerance = protection, most cells have MHC1 HLA-A and HLA-B, TBs have HLA-E, G and C, most HLA-E and G similar bw people but C is variable, if mat C detected it should be ignored
what are common pathologies if MHC HLA-C mismatch or immune system issues
recurrent miscarriage, PET, IUGR, or inflammation
describe recurrent miscarriage
failure of 3 or more consec clincially recognised conceptions >20K, causes inc paternal, infection, autoimmune, endocrine dysreg, uterine abnormality, fetal rejection due to mat system activation common
describe TH1, TH2, and Treg connection to miscarriages
TH1: increase involves cytokines inducing rejection
TH2: normally prevent rejection therefore low levels -> misc
TReg: downreg MHC in dendritic cells therefore low levels -> misc as recog fetus as foreihn
describe PET and TH1/2/reg levels
TH1 high and 2 and reg low
describe immune cells in stage 2
high level at mat;placental interface but not super active, will repair wound from implantation and decid remodelling, anti inflam stage = less capable of fighting off infection due to dampening
what is most common cause of preterm birth
mat infection spreading to placenta or infection ascending from vagina
