Innate Immunity Learning Questions Flashcards Preview

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Flashcards in Innate Immunity Learning Questions Deck (18):
1

What are 5 genetic deficiencies of the innate immune system?

1. Congenital neutropenia
2. Chronic granulomatous disease
3. Leukocyte adhesion deficiency (LAD)
4. Complement defects (various)
5. Chediak-Higashi Syndrome

2

What is congenital neutropenia?

(still have some protection due to NK cells)
-Lack of GM-CSF
-Frequent bacterial infections

3

What is chronic granulomatous disease?

-Inability to produce hydrogen peroxide and hypochlorous acid
-Inability to kill phagocytosed bacteria

4

What is leukocyte adhesion deficiency (LAD)?

-Lack of integrin subunit, the common beta chain
-Inability to recruit innate immune cells to site of inflammation
-Increased susceptibility to bacterial, fungal and viral infections

5

What are complement defects (various)?

-Increased susceptibility to bacterial infections
-Reduced ability to remove immunocomplexes

6

What is Chediak-Higashi syndrome?

-Defect in gene LYST (CHS1), a lysosomal trafficking gene that affects lysosomes and melanosomes
-Increased susceptibility to bacterial infections

7

What are defensins and cathelicidins?

-Major families of antimicrobial peptides
-Widely expressed in a variety of epithelial cells & sometimes leukocytes

8

What are defensins and cathelicidins?

-Major families of antimicrobial peptides
-Widely expressed in a variety of epithelial cells & sometimes leukocytes
-Most are short peptides (

9

What are defensins&cathelicidins role in the innate immune system?

Antimicrobial, chemotactic and regulatory activities
-Protect against bacteria, fungi, viruses and parasites
-Ancient arm of innate immune system that evolved to directly neutralize invading microbes
-100s of defensin proteins have been identified from amoeba, plants, birds, mammals, etc.

10

How are defensins and cathelicidins classified?

Based on their secondary structural features
-Cathelicidins (CAtionic HELical, bacteriCIDal proteIN) are alpha-helical peptides
--Human cathelicidin LL37 is highly expressed by PMNs and numerous mucosal and epithelial cell types
-Defensins are beta-strand peptides connected by disulfide bonds

11

What do Defensins and cathelicidins do to the cell membrane? What other function do they have?

-Interact with microbial cell wall membrane components to increase cellular permeability leading to cell death.
-They also act to modulate the inflammatory response

12

What are the two main classes of defensins?

Alpha and beta (based on linking pattern of the cysteines)

13

What is Alpha defensin?

-29-35 AA long
-Highly concentrated in granules of PMNs and Paneth cells of the small intestine
-Production is regulated by pro-inflammatory cytokines
-6 types of human alpha-defensins

14

Two types of alpha defensinL

1. Human neutrophil peptide (HNP) 1-4 are primarily expressed with PMNs, monocytes, and lymphocytes
2. Human defensins (HD) 5-6 are mainly expressed in Paneth cells

15

What is Alpha defensin?

-29-35 AA long
-Highly concentrated in granules of PMNs and Paneth cells of the small intestine
-Production is regulated by pro-inflammatory cytokines

16

Two types of alpha defensin:

1. Human neutrophil peptide (HNP) 1-4 are primarily expressed with PMNs, monocytes, and lymphocytes
2. Human defensins (HD) 5-6 are mainly expressed in Paneth cells

17

What is Beta defensin?

38-42 amino acids long, secreted by mucosal surface epithelia, including cells of the eye, skin, oral mucosa, urogenital and respiratory systems.

18

One type of Beta defensin:

-Human beta defensin (HBD) 1-4 are mainly expressed by various epithelial tissues (HBD4) is more limited to the testes and epididymis) but can also be expressed by monocytes, macrophages, and dendritic cells