Development of the Immune system Flashcards
When does hematopoiesis begin and where and at what week where does it change to
Begins week 4 in yolk sac
week 16 bone marrow assumes primary task of hematopoiesis
At the end of the first trimester what immune tissues does the fetus develop
fetus produces neutrophils and other innate cells including macrophages, monocytes, DCs and NK cels
-all demonstrate immaturity/reduced functionality
Circulating components (eg. compliment) is how much lower in fetuses compared to adults
10-80% lower than in adults (+ diminished activity)
@ what week does t cells move to thymus and what type of CD cell do they usually turn into
as early as week 6 (abundant in second trimester)
antigen exposure tends to polrize fetal CD4 cells into tregs and Th2
When do b cells start developing
around 9 weeks
What type of b cell is more abundant in this age group and function
B1 cells- spontaneously secrete low affinity igM with limited antigen specificities
(as we age the proportion of b2 cells outnumber b1 cells)
How many months does it take for immune tissues to start to function normally
3-6 months
what is unique about neonatal t and b cells
exclusively naive as there is no antigen encounters (no memory, proliferates poorly etc)
what maternal antibodies cross to the placenta and at what week + what is the receptor that allows for the transfer
maternal IgG cross into the placents starting at week 13
neonatal fc receptors
How long do maternal antibodies provide protection for
for up to a year but start to decline after 3 m
what is the window of vulnerabiluty for neonates
3-12 month due to low IgG and still not being able to make enough of own
when should vaccines not be given prior to
before 2 m
immune system graduallys matures in strength up to what age
18ish
Compared to males what differences does the female immune system have
increased CD4 and B cells (+ antibody production)
Comparedd to females what diffeernces does the male immune system have
greater number of CD8 and tREG numbers
