Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immuno Exam Block 2 :) > Lecture 20: Immunity to Microbes > Flashcards

Lecture 20: Immunity to Microbes Flashcards

1
Q

What do acute phase proteins CRP and SAP do?

A

Bind C1q on bacteria and activate complement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What role do C3a and C5a have in extracellular infections

A

Bind receptors on mast cells and activate them to release histamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What activates the endothelium and neutrophils in extracellular infection

A

Cytokines released from mast cells along with bacterial derived molecules (endotoxins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are two examples of potent neutrophil chemoattractants

A

C3a and C5a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Role of immature vs mature DCs in extracellular infections

A

Immature DCs engulf bacteria via PRRs, mature DCs migrate to local lymph nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What adhesion molecules are responsible for the adhesive interaction b/w lymphocytes and HEVs

A

L-selectin on lymphocytes

PNAds on HEVs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where do activated Th cells interact with B cells to promote affinity maturation/Ig class switching

A

Germinal centers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Endotoxins vs exotoxins

A

Endotoxin- Component of bacterial cell wall

Exotoxin- Secreted by bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Principal mechanisms of innate immunity to extracellular bacteria are

A

Complement activation
Phagocytosis
Inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Peptidoglycans (Gram+) and LPS (gram-) bacteria activate which pathways

A

Alternative and classical pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What causes the cleavage of C3b and C4b that prevents them from forming active convertases

A

Factor I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the cofactors for Factor I

A

MCP
CR1
Factor H
C4BP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What proteins inhibit assembly of C3 convertase in classical pathway

A

DAF
CR1
C4BP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What proteins inhibit assembly of C3 convertase in alternate pathway

A

DAF
CR1
Factor H

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the classical C3 convertase

A

C2aC4b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the alternative C3 convertase

A

C3bBb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can inhibit the assembly of the MAC

A

MAC-Inhibitory protein CD59

18
Q

Encapsulated bacteria rich in TI polysaccharide Ags are primarily eliminated by

A

Ab-mediated immunity

19
Q

What is the role of Th17 cells when activated by extracellular Ags, and what happens if there is a genetic defect in the Th17 cells

A

Promote local inflammation and recruit neutrophils and monocytes to the area
-Increased susceptibility to bacterial/fungal infections, with formation of multiple skin abscesses

20
Q

What is the role of Th1 cells when activated by extracellular Ag

A

Produce IFN-y which activates macrophages

May also stimulate production of IgG Abs

21
Q

What are the principal injurious consequences of host responses to EC bacteria

A

Inflammation and septic shock

22
Q

What causes the early phase of septic shock

A

Cytokines produced by macrophages

23
Q

Macrophages secrete TNF-a which does what

A

Upregulates Tissue Factor TF and nitric oxide synthase (iNOS)

24
Q

What is the role of IL-18 secreted by macrophages

A

Induces IFN-y which activates more macrophages

25
Q

What cytokine is a global suppressor of macrophage function

A

IL-10

26
Q

What are local effects of IFN-a in viral infections

A

Inhibition of viral gene replication
Up-regulation of MHC class I molecules
Activate NK cells early in infection

27
Q

What is the major mechanism used by bacteria to evade humoral immunity

A

Variation of surface Ags

28
Q

What activates NK cells at later stages of viral infections

A

IFN-y and IL-2 produced by Th1 cells

29
Q

What are Langerhans cells

A

Tissue DCs in the skin which transport Ag to local lymph nodes

30
Q

What molecules locally produced by macrophages and T cells have systemic effects of fever

A

IL-1 and TNF-a

31
Q

Naïve B cells acquire viral Ags through

A

Attachment to surface IgM or IgD

32
Q

Th1 cells recruit and stimulate virus specific CTLs by providing ____ for _____

A

IL-2 for proliferation of CD8+ T cells

33
Q

What are the key attributes of effector Th cells and CTLs in viral infections

A

Virus specific TCRs
Upregulation of adhesion molecule LFA-1
Upregulation of production of cytokines

34
Q

After death, viral secreted proteins are removed/neutralized by

A

Ab in the form of immune complex

Ab may guide Fc receptor-expressing NK cells

35
Q

When pathogenic bacteria are resisting degradation by phagocytic cells, this can be overrun by NK cells producing ____. Which cells release which cytokines to stimulate the NK cells to do this

A

Dendritic cells and macrophages produce IL-12 and IL-15 to activate NK cells to produce IFN-y which in turn promotes killing of phagocytized bacteria by macrophage

36
Q

Endogenous pathway of Ag presentation

A

Proteins from IC pathogens such as viruses are degraded by proteasome and the peptides are shuttled into the ER by TAP proteins and presented in MHC class I molecules

37
Q

Exogenous pathway of Ag presentation

A 
Extracellular pathogens are engulfed by phagosomes, in the phagosome, the peptides are loaded onto MHC class II molecules which activate Th cells to stimulate Ab production
(some peptides from exogenous pathway can be cross presented on MHC class I molecules)
38
Q

Fungi are recognized by what receptors

A

PRRs

39
Q

The detection of _____ by _____ is important for fungal infection

A

B-glucan by dectin 1

40
Q

What cytokines activate Th1, Th2 and Th17 cells

A 
Th1 = IL-12
Th2 = IL-4, IL-5
Th17 = TGF-b, IL-6
41
Q

In general, in fungal infections, Th1 responses do what, while Th2 responses do what

A

Th1 responses are required for clearance, while Th2 responses usually result in susceptibility to infection

42
Q

What is Dectin-1 role in fungal infections

A

Expressed on Macrophages. Binds and internalizes B-glucans and mediates activation of NF-kB and subsequent secretion of proinflammatory cytokines and ROS

Immuno Exam Block 2 :) (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions