Lecture 5: Innate Immunity (part 2) Flashcards Preview

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Flashcards in Lecture 5: Innate Immunity (part 2) Deck (29):
1

C3a, C4a, and  C5a have what effects

inflammation

2

C3b main function is 

opsonization and phagocytosis 

3

Although the 3 pathways of complement activation differ in how they are initiated, all of them result in the generation of enzyme complexes that are able to cleave the most abundant complement protein, ___

  • C3

4

The 3 complement pathwyas differ in how C3b is produced but follow a common sequence of reactions after the cleave of 

C5

5

What is the function of Properdin in complement 

  • Properdin stabilizes C3 convertases (C3bBb) on microbial surfaces

6

The classical pathway is initiated by binding of the complement protein ____ to the CH2 domains of IgG ro the CH3 domains of IgM molecules that have bound antigen

C1

7

C4 is homologous to ____

C3

8

Soluble C3a fragment stimulates ____ by acting as a chemoattractant for ____

inflammation, neutrophils

9

Soluble C5a is a very potent _____ that also induces changes in 

chemoattractant, permeability of blood vessels 

10

The classical activation pathway requires 

  • IgM or IgG and C1

11

What is C3 convertase and C5 convertase in the lectin and classical activation pathways

  • C4bC2a (C3 convertase)
  • C4b2aC3b (C5 convertase) 

12

What is the C3 and C5 convertase in alternative pathways 

  • C3bBb (C3 convertase)
  • C3bBbC3b (C5 convertase) 

13

C1q binds to ___ portion of antibody

Fc

14

In the alternative pathway C3b is capable of binding factor B that can be cleaved into Ba and Bb by the constitutively active serum protease 

factor D 

15

Mannose-binding lectin has a hexametric structure similar to the ___ component of the classical pathway

C1q (which makes sense because they begin similar and have the same C3 convertase components)

 

16

After mannose-binding lectin (MBL) binds to microbes, two zymogens called _____ and _____ (mannose-associated serine protease) are activated they have similar functions to ____ and _____ and initiate downstream proteolytic steps identical to the classical pathway

  • MASP1 and MASP2
  • C1r anC1s

17

Pulmonary surfactant proteins SP-A and SP-D are members of the ____ family. fxn?

  • collectins 
  • act as opsonins, facilitating phagocytosis by alveolar macrophages

18

What are Ficolins

humoral molecules (PRRs) of the innate immune systems which recognize N-acetylglucosamine and lipoteichoic acid on pathogens, apoptotic, and necrotic cells (activate the lectin pathway)

19

Complement is not activated on the surface of mammalian cells because they express regulatory proteins that inhibit, disassemble, or cleave the convertases. Examples?

  • Decay-Accelerating Factor (DAF)
    • blocks C2:C4b interaction
    • enhance dissociation of C4bC2a interaction
  • Complement receptor 1 (CR1)
    • enhanc dissociation of C4bC2a
    • cleave C4b and C3b
  • Factor I (FI)
    • clave C4b and C3b

20

What is the strongest anaphylatoxin of the complement cascade

C5a (it has the strongest effects and it is the only one that effects Chemotaxis, release of Oradicals and lysosomal enzymes

21

____, ____, and ___ mediate protective systemic effects of inflammation, including induction of fever, acute-phase protein synthesis by the liver, and increased production of leukocytes by the bone marrow

  • TNF
  • IL-1
  • IL-6

22

Acute phase proteins are several plasma proteins that recognize microbial structures and participate in innate  immunity belong ot the ____ family. Examples: 

  • pentraxin 
  • Ex: C-reactive protein (CRP) and Serum amyloid P (SAP)

23

CRP and SAP recognize ____ and ____ respectively, which are found on bacteria and apoptotic cells 

  • CRP recognizes phosphorylcholine
  • SAP recognizes Phosphatidylethanolamine

24

The increased levels of CRP and SAP are a result of increased synthesis by the liver induced by the cytokines ___ and ____

IL-6 and IL-1

 

25

CRP and SAP can activate the complement by binding ____ and initiating the ___ pathway

C1q and initiating the classical pathway

26

IFN-alpha and IFN-beta bind to receptors on neighboring uninfected cells and activate _______ signaling pathways

JAK-STAT

27

Inactive JAK (Janus kinases) are non-covalently attached to the cytoplasmic domains of Type ___ and Type ____ cytokine receptors 

 

Type I and Type II

 

28

IFN-alpha and IFN-beta bind to receptors on neighboring unifected cells and activate ____ signaling pathways

JAK-STAT

29

Type I interfeurons bind to receptors on unifected cells and activate JAK-STAT signaling pathways meanwhile they also bind to receptor on infected cells and 

induce expression of genes whose products enhance the cell's susceptibility to CTL-mediated killing