100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Summary Advanced Immunology Janeway test 1) Innate immunity, complement & phagocytosis $5.88
Add to cart

Summary

Summary Advanced Immunology Janeway test 1) Innate immunity, complement & phagocytosis

 116 views  0 purchase
  • Course
  • Institution
  • Book

This is a small summary for the course advanced immunology from the master biomedical sciences at the UvA. It includes all the information you need for one of the 9 Janeway tests during this course. Look out for the bundle, because that's a lot cheaper!

Preview 2 out of 6  pages

  • Unknown
  • November 6, 2019
  • 6
  • 2019/2020
  • Summary
avatar-seller
Innate immunity, complement & phagocytosis – Ilse
Jongerius
2-5
Lectin pathway: Initiated by
mannose binding lectin (MBL)
and ficolins that recognise
carbohydrate structures on
microbial surfaces. MBL-
associated serine proteases
(MASPs) associate with MBL
and ficolins and trigger the rest
of the pathway.

Classical pathway: Initiated by
C1 (consists of recognition
protein C1q and proteases C1r
and C1s). C1q recognises
microbial surface or
antibodies.

Alternative pathway:
Spontaneous hydrolysis and
activation of C3 (bind directly
to microbial surfaces).

Any pathway  C3 convertase is activated  cleaves C3  C3b (main effector) & C3a (small peptide
 binds receptors  induce inflammation).

C3b binds covalently to surface  acts as opsonin  phagocytes can destroy microbe.

C3b can also bind to C3 convertase  C5 convertase is formed  cleaves C5 into C5a and C5b.

 C5b helps form the membrane attack complex (MAC).
 C3b: Thioester bond can react with hydroxyl or amino group on microbial surface.  no
bond  hydrolyse thioester  inhibition alternative pathway
 Key activated complement components are rapidly inactivated unless they bind to a
pathogen (otherwise potentially dangerous).
 Regulatory proteins protect host cells by preventing activation on their surfaces.
o Unless they undergo apoptosis (helps limiting risk autoimmune response).

2-6
Microorganisms have PAMPs (pathogen associated molecular patterns).

 Gram positive: Lipoteichoic acids.
 Gram negative: Lipopolysaccharide.

Mannose binding lectin (MBL) is a receptor that circulates in blood and other fluids and triggers the
lectin pathway and is synthesised in the liver. Amino terminus: collagen-like domain, carboxy
terminus: lectin domain (protein called collectins). In the blood it consists of 2-6 trimers (main form

, trimers and tetramers). 1 MBL has low affinity (for mannose, fucose, GlcNAc) but multimers have a
high total binding strength (avidity) for repetitive carbohydrate structures.

 Production increased during infection (acute-phase response).

Ficolins (more abundant dan MBL): Have a fibrinogen-like domain and a collagen-like domain.
Fibrinogen-like domain gives the specificity for oligosaccharides with acetylated sugars (not
mannose). We have 3 forms L & H (synthesised by liver) and M (lung and blood).

MBL in plasma forms complexes with MBL-associated serine proteases MASP-1, MASP-2 & MASP-3.
MBL binds with a pathogen surface  conformational change MASP-1  it cleaves and activates
MASP-2  it cleaves C4 and C2.

 Ficolins also form complex with MASP-1 and MASP-2 etc.

When C4 is cleaved (also thioester bond)  releases C4a  C4b has reactive thioester  binds to
microbial surface  binds C2. C2 is cleaved by MASP-2 producing C2a  binds to C4b to form C4b2a
(=C3 convertase in lectin pathway). This cleaves many C3 into C3a and C3b.

 Defect in MBL or MASP-2: Respiratory infections by common bacteria in early childhood.
 SP-A and SP-D (surfactant proteins): Collectin proteins, coat surface of pathogens for
phagocytosis. No complement (no association with MASPs).




2-7
Classical pathway uses C1 as pathogen sensor. C1q is the pathogen sensor and C1r and C1s are serine
proteases. C1q is a hexamer of trimers. Amino terminal: globular domain, Carboxy terminal:
collagen-like domain. C1r and C1s are closely related to MASP-2.

C1q recognises a pathogen  conformational change in C1r, C1s complex  activation of
autocatalytic enzymatic activity in C1r  cleaves C1s to active serine protease. C1s cleaves C4 to
produce C4b (leading to C4b2a again).

C1q can bind to the surface of pathogens in different ways:

 Binding directly to surface components (proteins cell wall, lipoteichoic acid gram positive).
 Binding to C-reactive protein (acute phase protein, binds to phosphocholine residues on the
bacterial surface)

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller nadinevankleef. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $5.88. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

53068 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$5.88
  • (0)
Add to cart
Added