acute phase proteins and collectins

Question 1

Can MBL act as an opsonin as well as activating complement?

Answer 1

yes

Question 2

What are the three pnetraxins? where can they be produced?

Answer 2

CRP and SAP- acute phase proteins produced by liver in response to IL-6, Il-1B and TNFa.

PTX3 can be produced by liver but also locally by cells like monocytes and DCs.

Question 3

What are the collectins?

Answer 3

MBL, SP-A and SP-D.

Question 4

What can the effects of pentraxins be?

Answer 4

Can act as opsonins, they can activate complement via C1q and can be bound on apoptotic cells (C1q calreticulin and CD91).

Question 5

effects of TNF-a on bone marrow neutrophils, DCs and body temperature?

Answer 5

Can increase mobilisation of neutrophils and act on hypothatlums as a pyrogen.
Can induce DC maration and migration to the lymph.

Question 6

What is role of thromins? And what can activate their activity?

Answer 6

thrombin can break down fibrinogen into fibrin to form clots. MASP1 and 2 can activate thrombin, and also directly target fibrinogen.

Question 7

4 acute phase proteins?

Answer 7

CRP, fibrinogen, a-2-macroglobulin (portease inhibitor) and serum amyloid A.

Question 8

What on microbes can CRp bind?

Answer 8

phosphorycholine to act as an opsonin.

Question 9

How can a-2-macroglobulins and serpins help infection?

Answer 9

prevent proteases produced from bacteria haveing negative effects.

Question 10

what other things in PTX3 involved in apartf rom innate immunity?

Answer 10

tissue remodelling (matrix deposition) e.g. wound healign and fertility.

Question 11

what collectins are found in the phospholipid surfacatn layer in the lungs? What cells are they produced by?

Answer 11

Sp-A and SP-D produced by type 1 alveolar cells.

Question 12

Where else apart from lungs are the SP-a and SP-D found?

Answer 12

at mucousal surfaces.

Question 13

Strucutre of colelcitns?

Answer 13

collagenous domain with C type lectin binding domain (trimeric building blocks).
MBL and SP-A look similar to C1q, Sp-D like a cross- 4 head domains.

Question 14

What is collectin binding dependent on?

Answer 14

Ca2+.

Question 15

What are four functions of collectins like SP-A and SP-D?

Answer 15

they can agglutinate pathogens. even causing lysis alone. Can opsonise for phagocytosis of apoptotic cells and pathogens,.

Question 16

What lung disorders are associated with SP-D deficincey?

Answer 16

COPD and ARDs

Question 17

what fungus can be fatal (common in CGD patients) What treatment is protective?

Answer 17

Aspergillus infection, Sp-D was protective.

Question 18

How can both SP-A and SP-D prevent the IgE response in allergens?

Answer 18

By competing with IgE by binding to allergens- blocks histamine release.

Question 19

What collectin can block eosinophilia?

Answer 19

SP-D prevented eosinophilia, induced IL-5 induced eosinopholic apoptosis.
AlSO enhanced their phagocytosis.

Question 20

How could SP-D affect immune cells to alter the allergy response?

Answer 20

Increased their production of TNF a and IL-12, to skew towards a Th1 response.

Question 21

How did Sp-A cells affect DCs?

Answer 21

they suppressd DC maturation, increased DC secretion of IL-10, decreased IL-12 and TNF-a.

Question 22

Can rhSP-D induce apoptosis of cancer cells?

Answer 22

Yes can do this by interuppting cell cycle in a variety of cancers.

Question 23

How else can SP-D inhibit cancer cells?

Answer 23

by preventing their migration and EMT transition.

Question 24

What pathways does SP-D use to inhibit cancer cells?

Answer 24

Versatility to affect multiple pathways in cancer cells!