Neonatal Immunology

Question 1

Explain FcRn

Answer 1

Receptors in baby that bind to IgG in mother and help bring it into babies blood supply. This gives baby immune protection at birth.

Question 2

Why are AB not destroyed in baby gut from breast milk?

Answer 2

Baby has low proteolytic activity in their guts at birth.

There are Fc receptors in the gut that transport IgG from intestine into circulation.

Question 3

Explain baby’s window of susceptibility

Answer 3

From 2-6 months, there is a time period where Mom’s IgG has dropped and baby’s production hasn’t established itself. It is the time of most vulnerability to infection.

*vaccinations usually aren’t given in this window.

Question 4

Explain the changes in aging bone marrow, and its correlation to immunology.

Answer 4

All adaptive cell production lowered except for NK cell.

Produced B and T cells don’t function as well

IL-7 is decreased which usually signals antiapopototic measures to T-cells.

Question 5

Explain adaptive immunity changes with age

Answer 5

CD4 to CD8 ratios change. More 8 than 4.

There are less naive cells and more old memory cells making adaptation to new infections difficult.

Increase in serum and salivary IgA

Decrease in allergic hypersensitivity because there are lower IgE levels

Question 6

State changes to specific cells in the immune system with aging:
Neutrophils
Macrophages
Dendritic Cells
NK Cells

Answer 6

Neutrophils: Less cytotoxicity, lower phagocytosis, short lived

Macrophages: Less TLR expressed, lower phagocytosis

Dendritic Cells: Lower numbers in skin, impaired chemotaxis

NK Cells: Increased numbers, impaired cytotoxicity, less cytokines