Host Defense: Integration & Physiology Flashcards Preview

Physiology Exam 3 > Host Defense: Integration & Physiology > Flashcards

Flashcards in Host Defense: Integration & Physiology Deck (29):
1

What are antimicrobial peptides?

Gene-encoded, small (10-45 AAs) cationic peptides

2

Antimicrobial peptides are active against?

1. Bacteria
2. Fungi
3. Viruses

3

3 antimicrobial peptides

1. Defensins
2. Cathelicidins
3. Hepcidins

4

How are defensins and IBD connected?

IL-1beta

5

4 defensins in the intestine

1. HNP-1
2. HD-5
3. Crp-3
4. Crp-4

6

IL-1 system

Keeps WMD under tight control

7

IL-1

1. Endogenous pyrogen
2. Lymphocyte activating factor
3. Catabolin

8

Loss of control of IL-1beta secreation leads to?

Systemic inflammation:
1. Familial cold auto-inflammatory syndrome (FCAs)
2. Muckle-Wells syndrom

→ reccurent episodes of rash, fever and joint pain

9

Catabolin

Cartilage catabolic factor

10

How is IL-1beta initially synthesized?

Inactive proIL-1beta after LPS stimulation

11

Posttranslational processing and release of IL-1beta

Second stimulas (ex: 1 mM ATP) required for efficient processing and release

12

Agents that promote IL-1beta maturation and release in vitro

1. ATP (1mM) via activation of P2X7 receptor (cation channel)
2. Clostridium difficile toxin-A
3. Staphylococcal alpha-toxin

13

Effect of human defensins on release of proIL-1beta from LPS-activated human PBMC

Inhibit

14

Effect of defensins on ATP-mediated IL-1beta release from LPS-activated human PBMC

Block

15

Defensins are ______ regulators of IL-1beta

Negative regulators

16

What is IBD?

1. Chronic disorder causing inflammation of digestive tract
2. Includes Crohn's disease and ulcerative colitis
3. Can occur at any age → 1 mil Americans have IBD

17

IBD clinical signs

1. Persistent diarrhea
2. Abdominal pain
3. Fever
4. Rectal bleeding (sometimes)

18

Environmental factors leading to IBD

1. Diet
2. Stress
3. Pathogens
4. Smoking

19

Genetic factors leading to IBD

Familial and multigenic → cytokine gene (IL-23) polymporphisms, NOD2 mutation

20

Immunological factors leading to IBD

1. Defective immune system (abnormal recognition of ubiquitous antigens)
2. Altered cytokine production (increased procution of other soluble mediators)

21

NOD stands for?

Nucleotide-biding and oligomerization domain

22

What is NOD2?

Intracellular receptor for MDP

23

DMP

Muramyl dipeptide

Conserved bacterial cell wall component

24

NOD2 role

Initiating immune responses against cytoinvasive pathogens

25

NOD@ mutations are associated with?

Reduced mucosal defensin expression in CD

26

DSS

Dextrane sulfate sodium → can induce colitis

27

Defensin deficiency can cause?

Over-production of IL-1beta → uncontrolled intestinal inflammation → IBD

28

How do defensins affect activity of IL-1beta-converting enzyme (ICE) capase-1

Do not inhibit

29

How do defensins affect release of TNF-alpha from LPS-activated monocytes?

Do not inhibit