Immuno complement system Flashcards
What is opsonization?
Marking antigen to promote phagocytosis (phagocyte has receptors)
What molecules can opsonize antigens?
immunoglobulins and complement system
What are natural antibodies?
General antibodies produced by a sub-category of B-cells for innate immunity (limited specificity).
they recognize common molecular patterns that arent proteins.
Mostly IgM.
What is pentraxin and some examples?
pentameric proteins including CRP, serum amyloid P, and pentraxin PTX3
What do CRP and SAP do in the body?
bind to a few PAMPs and DAMPs and c1q to initiate classical pathway.
What are collectins?
a family of trimeric or hexameric proteins using a calcium dependent lectin head.
What are mannose binding lectins?
which is a soluble pattern recognition receptor that binds carbohydrates with terminal mannose and fucose, activates the lectin pathway of complement activation
What are ficolins?
Ficolins are plasma proteins that are structurally similar to collectins, possessing a collagen-like domain, but instead of a C-type lectin domain, they have a fibrinogen-type carbohydrate recognition domain.
What are the main inflammatory molecules and from what cells are they produced?
IL-1 IL-6 TNF alpha
by neutrophils and macrophages mainly.
What acute phase protein is usually used for identification of acute inflammation?
CRP, its baseline is really low without infection.
What is the complement system and how is it activated?
The complement system is a group of proteins that circulate the blood in inactive form, until a pattern is sensed with proteins like (C1q, Lectins) which leads to a series of reactions of protein cleavage and activation
What C fragments act as opsonins?
C3b C4b
What C fragments act as anaphylatoxins?
(inflammation) C3a C5a
What happens when there is a complement system deficiency, give an example disease.
increased infection susceptibility and autoimmune risk like systemic lupus erthematosus
How many pathways are there for C activation and what is the most crucial step?
3 pathways, classical, lectin, and alternative.
All of them converge at the C3 convertase step. Alternative uses C3bFb to make the C3 convertase while the rest use C2bC4b.
