Host Defense: Antimicrobial Peptides Flashcards Preview

Physiology Exam 3 > Host Defense: Antimicrobial Peptides > Flashcards

Flashcards in Host Defense: Antimicrobial Peptides Deck (25):
1

The Lederberg Experiment found?

Many mutations are random, not directed → penicillin-bacteria were there before they met penicillin

2

2 types of antimicrobial peptides

1. PMN
2. Neutrophils

3

2 types of AMPs

1. Cathelicidins
2. Defensins

4

Effector host defense peptides

Very diverse, very species-specific

Kill microbes and have host-defense activities

5

2 porcine cathelicidins

1. PR-39 (proline rich)
2. PG 1-5 (protegrin)

6

2 bovine cathelicidins

1. Bac-5
2. Bac-7

(Bac = bactenecins)

7

Human cathelicidin

LL-37I

8

Porcine beta defensin

pBD-1 (porcine beta defensin)

9

3 bovine beta defensins

1. TAP (tracheal antimicrobial peptide)
2. LAP (lingual antimicrobial peptide)
3. EBD (enteric beta densin)

10

Human alpha defensin

Human neutrophil peptide 3

11

Monkey zeta (or theta) defensin

Rhesus TD-1

12

3 mini-defensins

1. Retrocyclin (human)
2. Rhesus TD-1 (monkey)
3. Protegrin-1 (pig)

13

Defensins form?

Pores

14

Defensins are categoried on?

Common patterns of cysteine residues

15

Human alpha-defensins found in?

1. Neutrophils
2. Intestinal crypt cells (Paneth)
3. Urogenital tract

16

Beta-defensins have what type of antimicrobial spectrum?

Broad antimicrobial spectrum

17

Theta-defensin

Present in Old-World monkeys; pseudogene in humans, chimps and gorillas

18

Host-defense peptides are?

Naturally occurring antibiotics → functional in innate immunity

19

Host-defense peptide functions

1. Protect from invasion by broad range of microorganisms: bacteria, fungi, viruses and metazoan parasites
2. Interact with other host-defense systems that complement their roles as antibiotics

20

Host-defense peptide mechanisms of action

1. Pore-forming
2. LPS-binding
3. Interference with microbe's intracellular metabolism

21

Host-defense peptide structure and binding

Amphipathic structure, bind tightly to anionic bacterial sufaces

22

Why is it difficult for microbes to develop resistance to host-defense peptides?

Very difficult to change microbes' cell-surface biochemistry

23

Future directions in host-defense peptide research

1. Understand their physiologic significance
2. Understand AMP regulation mechanisms
3. Develop constructs and vectors for AMP drug delivery
4. Understand structure/function relationships of AMPs
5. Understand how peptides interact with rest of immune system
6. Develop clinical uses

24

Beta-defensins are chemotactic

1. Dendritic cells
2. T cells

25

Beta-defensins activate?

1. Mast cells
2. Monocyte expression of IL-1 and TNF-alpha