IMM2022 Study Guide - Final Guide: Fragment Crystallizable Region, Immunoglobulin G, Endothelium
12 May 2018
School
Department
Course
Professor
Isotype
Function
Production
stimulated by
Structure
Distribution
Role in adaptive
IMM
Serum conc and
serum half life
IgA
- Mucosal IMM
- Secretion of IgA into the lumens of GI
and respiratory tract, neutralisation
of microbes and toxins
- Transport through epithelia
- Most abundantly produced isotype
with grams produced daily and
secreted across gut epithelium
- Has an associated secretory
component
- Binds to poly-Ig receptor found on
basal surface required for transport
across gut epithelium
- And protected from degradation in
the gut
- Given to neonate through breast milk
- Neutralisation
- Transferred through breast milk
- IgA plasma cells home and
accumulate in breast and secrete into
the breast milk (IgM is also present in
milk)
Helper T-cells:
CD40L, cytokines
Cytokines
produced in
mucosal tissues eg
TGF-Beta, BAFF
Dimer –
joined
together by
a J chain
Dimer
protects
proteolytic
breakdown
Transport across
epithelium (main
one)
IgA levels in
serum are low
and tend to be
monomeric (not
dimers)
because all is in
gut
- Viral influenza
- Extracellular
bacteria
- Toxins
- 3,5mg/ml
- 6 days
- Is low
conc. But
is pumped
in large
amounts
into
secretions
IgG
- Neutralisation of microbes and toxins
- Opsonisation of antigens for
phagocytosis by macrophages and
neutrophils
- IgG is an opsin
- elimination: the process by which
certain cells of innate immunity
Monomer
- Viruses
- Extracellular
bacteria (main
one for this)
- Toxins
- 13.5mg/ml
- 23 days
(macrophages and neutrophils engulf
microbes for destruction)
- Activation of the classical pathway of
complement
- Ab-dependent cellular cytotoxicity
mediated by NK cells
- Neonatal immunity: transfer of
maternal An across placenta and gut
- Feedback inhibition of B-cell
activation
Transported across placenta and has
increased half-life in the circulation role
of the Fc neonatal receptor
- The Fc region of IgG can bind to the
neonatal Fc receptor (FcRn) found on
endosomes (found in placenta,
endothelial cell, phagocytes)
- This is the endocytosis process for
transport)
- Protects molecule from degradation
- Increases LE of 3 weeks
Note: in non-pregnant people this is
occurring in our endothelial cells.
1
- Fc receptor dependent phagocyte
responses
- Complement activation
- Neonatal immunity (placental
transfer)
- Neutralisation
- Opsonisation
- Sensitization for killing by NK cells
- Can then switch to IgE only case
where this can happen
Helper T-cells:
CD40L, cytokines
IL-10 (human)
IFN-gg (mouse)
Transport across
placenta (main
one)
Diffusion into
extravascular
sites
Document Summary
Dimer joined together by a j chain. Iga levels in serum are low and tend to be monomeric (not dimers) because all is in gut. Cytokines produced in mucosal tissues eg tgf-beta, baff. Secretion of iga into the lumens of gi and respiratory tract, neutralisation of microbes and toxins. Most abundantly produced isotype with grams produced daily and secreted across gut epithelium. Binds to poly-ig receptor found on basal surface required for transport across gut epithelium. And protected from degradation in the gut. Iga plasma cells home and accumulate in breast and secrete into the breast milk (igm is also present in milk) Elimination: the process by which certain cells of innate immunity. But is pumped in large amounts into secretions. 23 days (macrophages and neutrophils engulf microbes for destruction) Activation of the classical pathway of complement. Ab-dependent cellular cytotoxicity mediated by nk cells. Neonatal immunity: transfer of maternal an across placenta and gut.
