Quiz 2 Flashcards
What are the goals of the complement system?
anaphlaltoxins
MAC
opsonization
What is complement fixation?
attachment of protein fragments to the surface of pathogens marking them for phagocytosis and avoiding host cells
What is the membrane attack complex (MAC)?
5 subunit complex that forms pores in pathogens
What is an anaphylatoxin?
complement protein fragments that induce inflammation
What is the first complement pathway to activate and why?
alternative pathway; its proteins circulate the blood
What 2 complement pathways require inflammation to activate?
lectin and classical
What is the C3 convertase for the alternative pathway?
C3Bb
What is the C3 convertase of the lectin pathway?
C4b2b
What is the C3 convertase of the classical pathway?
C4b2a
What do all 5 of the MAC subunit do?
C5b, C6, C7 bind together exposing C7’s hydrophobic site so it can insert into the pathogen
C8 binds to the rest of complex as a docking site for C9
What are the 2 MAC regulation proteins?
plasma proteins
cell-surface proteins
How do PLASMA MAC regulation proteins prevent host cell damage?
prevent soluble C6 and C7 from binding to host cells
How do CELL-SURFACE MAC regulation protein prevent host cell damage?
prevents C9 recruitment
What are 3 examples of plasma MAC regulation protein?
- S protein
- clusterin
- factor J
What are 2 examples of cell-surface MAC regulation protein?
- CD59 (protectin)
- HRF
What are 2 examples of anaphaltoxins in the alternative complement pathway?
C3a and C5a
What 3 places do alternative anaphalatoxins bind and why?
- endothelial cells (increase blood flow)
- granulocytes (induce degranulation)
- phagocytes (attract phagocytes)
What do protease inhibitors do and an example?
inhibit bacterial proteases
alpha 1-macroglobulin: traps microbes like a venus fly trap
What do defensins do?
poke holes in pathogen membrane
What kinds of cells express alpha-defensins?
neutrophils and paneth cells
What kinds of cells express beta-defensins?
epithelial cells
What cell is involved in the most common immunodeficiencies?
B cells
What is the difference between primary and secondary immunodeficiencies?
primary - inherited
secondary - aquired
Primary immunodeficiencies are ______ which tend to be rare
monogenic
What are the 5 categories of immunodeficiencies?
- physical/microbial
- complement
- pattern recognition receptors
- phagocytic
- NK cells
What are 2 examples of microbial immunodeficiencies?
- cystic fibrosis
- crohns
What are 3 examples of complement immunodeficiencies?
- Factor H/I
- MAC deficiency
- C1, 2, 3, 4 deficiency
What is an example of a PRR immunodeficiencies?
recurrent HSE (herpes)
What are 3 examples of phagocytic immunodeficiencies?
- leukocyte adhesion deficency
- Chediak-Higashi syndrome
- chronic granulomatous disease
What are 2 examples of NK cell immunodeficiencies?
- classical NK cell deficiency
- Functional NK cell deficiency
How is cystic fibrosus an immunodeficiency?
mucous formed is too thick causing biofilms ; CFTR protein is faulty
How is crohns disease an immunodeficiency?
paneth epitheial cells lack expression of a-definsins causing increased microflora
How is Factor H and I deficiency an immunodeficiency?
Factor H and I cleave C3b to make iCb3 which stops complement
without complement is over activated and C3 is depleted from serum
How is improper formation of MAC an immunodeficiency?
if any of the 5 subunits are messed up MAC wont form
How is Hereditary Angioneurotic Edema (HANE) an immunodeficiency?
improper activation of classical C3 convertase causing non-specific cleavage of C2 and C4 causing inflammation that doesn’t respond to medication and protein depletion in plasma
What is pyogenic bacteria?
induces acute neutrophilic inflammation and pus
How is recurrent HSE an immunodeficiency?
PRR signaling is impaired causing a NK cells to not do their job and viral replication to be uncontrolled (INF not working)
How is leukocyte adhesion deficiency (LAD) an immunodeficiency?
cell is not able to bind to microbe
tight binding for neutrophils impaired because b2-integrin doesn’t work
How is Chediak-Higagi syndrome an immunodeficiency and what does it cause on the cellular level of other immune cells?
phagosome cannot bind to to lysosome to create phagolysosome
causing giant granules and deficient NK cells
How is Chronic Degranulomatous syndrome an immunodeficiency?
NADPH oxidase doesn’t work and cell degradation doesn’t happen
causing neutrophil build up
How is classical NK cell deficiency an immunodeficiency?
absence of very low number of NK cells
How is functional NK cell deficiency an immunodeficiency?
defective NK cells where Fc receptor cannot interact with microbe
_______ binds to all C3 convertases to create C5 convertases which is cleaved into C5a and C5b to create MAC
C3b
Is C5a or C5b the beginning of the MAC?
C5b
What is the job of Properdin (Factor P)?
protects alternative C3 convertase on pathogen’s surface
What is the job of Factor H and I?
cleaves bound C3b making it inactive (stopping complement)
What are the two PLASMA C3b regulating proteins?
- Properdin (Factor P)
- Factor H and I
What are the two MEMBRANE C3b regulating proteins?
- Decay-accelerating factor (DAF)
- Membrane cofactor protein (MCP)
What is the job of Decay-accelerating factor (DAF) and Membrane cofactor protein (MCP)?
protects host cells (disassembling of alternative C3 convertase)
