acute phase proteins and collectins Flashcards
(24 cards)
Can MBL act as an opsonin as well as activating complement?
yes
What are the three pnetraxins? where can they be produced?
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.
What are the collectins?
MBL, SP-A and SP-D.
What can the effects of pentraxins be?
Can act as opsonins, they can activate complement via C1q and can be bound on apoptotic cells (C1q calreticulin and CD91).
effects of TNF-a on bone marrow neutrophils, DCs and body temperature?
Can increase mobilisation of neutrophils and act on hypothatlums as a pyrogen.
Can induce DC maration and migration to the lymph.
What is role of thromins? And what can activate their activity?
thrombin can break down fibrinogen into fibrin to form clots. MASP1 and 2 can activate thrombin, and also directly target fibrinogen.
4 acute phase proteins?
CRP, fibrinogen, a-2-macroglobulin (portease inhibitor) and serum amyloid A.
What on microbes can CRp bind?
phosphorycholine to act as an opsonin.
How can a-2-macroglobulins and serpins help infection?
prevent proteases produced from bacteria haveing negative effects.
what other things in PTX3 involved in apartf rom innate immunity?
tissue remodelling (matrix deposition) e.g. wound healign and fertility.
what collectins are found in the phospholipid surfacatn layer in the lungs? What cells are they produced by?
Sp-A and SP-D produced by type 1 alveolar cells.
Where else apart from lungs are the SP-a and SP-D found?
at mucousal surfaces.
Strucutre of colelcitns?
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.
What is collectin binding dependent on?
Ca2+.
What are four functions of collectins like SP-A and SP-D?
they can agglutinate pathogens. even causing lysis alone. Can opsonise for phagocytosis of apoptotic cells and pathogens,.
What lung disorders are associated with SP-D deficincey?
COPD and ARDs
what fungus can be fatal (common in CGD patients) What treatment is protective?
Aspergillus infection, Sp-D was protective.
How can both SP-A and SP-D prevent the IgE response in allergens?
By competing with IgE by binding to allergens- blocks histamine release.
What collectin can block eosinophilia?
SP-D prevented eosinophilia, induced IL-5 induced eosinopholic apoptosis.
AlSO enhanced their phagocytosis.
How could SP-D affect immune cells to alter the allergy response?
Increased their production of TNF a and IL-12, to skew towards a Th1 response.
How did Sp-A cells affect DCs?
they suppressd DC maturation, increased DC secretion of IL-10, decreased IL-12 and TNF-a.
Can rhSP-D induce apoptosis of cancer cells?
Yes can do this by interuppting cell cycle in a variety of cancers.
How else can SP-D inhibit cancer cells?
by preventing their migration and EMT transition.
What pathways does SP-D use to inhibit cancer cells?
Versatility to affect multiple pathways in cancer cells!
