Lecture 122/123

Question 1

What is the action of lysozymes?

Answer 1

Breaks down bacterial cell walls (peptidoglycan)

Question 2

What is the action of defensins and cathelicidins?

Answer 2

Antimicrobial peptides that disrupt microbial membranes

Question 3

What cytokines can activate the NK-kB transcription factor?

Answer 3

TNF-a, IL-1, IFN-y

Question 4

What are the roles of TNF-a?

Answer 4

Pro-thrombotic, leukocyte adhesion/migration, macrophage activation, hematopoiesis, lymphocyte development

Question 5

Four major plasma enzyme systems:

Answer 5

1. Clotting
2. Fibrinolytic (plasmin)
3. Kinin (bradykinin)
4. Complement

Question 6

What is the role of fibrinolytic agents (i.e. plasmin)?

Answer 6

Tissue repair, remodeling, dissolves fibrin clots, promotes angiogenesis

Question 7

What is the role of kinins (i.e. bradykinin)?

Answer 7

Vasodilation, increased vascular permiability, smooth muscle contraction, pain

Question 8

What is the role of complement?

Answer 8

Opsonization, microbial lysis, chemotaxis, and inflammation

Question 9

What cytokines are responsible for mast cell degranulation (anaphylatoxins)?

Answer 9

C3a/C5a

Question 10

Name an exogenous pyrogen

Answer 10

LPS (from Gram-negative bacteria)

Question 11

IL-1, IL-6, and TNF-a are all

Answer 11

endogenous pyrogens

Question 12

IFN-a is produced by ____

Answer 12

Dendritic cells

Question 13

IFN-B is produced by ____

Answer 13

Fibroblasts

Question 14

IFN-y is produced by ____

Answer 14

T-cells/NK cells

Question 15

____ and ____ activate an RNA-dependent protein kinase that blocks mRNA synthesis and can trigger apoptosis in infected cells

Answer 15

IFN-a and IFN-B

Question 16

____ enhances macrophage activation and MHC expression

Answer 16

IFN-y

Question 17

The classical complement pathway is triggered by ____ and requires ____

Answer 17

Triggered by antibodies (IgM, IgG), and requires Ca2+

Question 18

The alternative complement pathway is triggered by ____ and requires ____

Answer 18

Triggered by pathogen surfaces (LPS) and requires Mg2+ and factor B

Question 19

The lectin complement pathway recognizes ____

Answer 19

Microbial carbohydrates

Question 20

What complement components coat pathogens to enhance phagocytosis?

Answer 20

C3b and C4b

Question 21

What is the role of CD59 in the complement system?

Answer 21

Prevents C9 binding and formation of MAC on host cells

Question 22

Clinical condition:

Deficiency of CD59 causes:

Answer 22

Paroxysmal nocturnal hemoglobinuria (PNH)

Question 23

Clinical condition:

Hereditary angioedema is caused by:

Answer 23

C1 inhibitor deficiency in the complement system

Question 24

What is the result of a C3 deficiency in the complement system?

Answer 24

Severe recurrent infections, especially with encapsulated bacteria (Neisseria infections)

Question 25

C1, C2, and C4 deficiencies of the complement system result in what?

Answer 25

Poor clearance of immune complexes, increasing risk of type III hypersensitivity

Question 26

Which phagocytic cell readily procudes oxygen radicals?

Answer 26

Neutrophils

Question 27

During the fusion stage of phagocytosis, the phagosome fuses with ____

Answer 27

Lysosome

Question 28

Which phagocytosis intracellular receptor forms inflammasomes and can trigger cell death and IL1B/IL-18 release?

Answer 28

NOD-like receptors (NLRs)

Question 29

Which phagocytosis intracellular receptor detects viral dsRNA?

Answer 29

RIG-I-like helicase (RLH)

Question 30

How does Mycobacterium tuberculosis evade phagocytosis?

Answer 30

Blocks phagolysosome fusion

Question 31

M1 macrophages are:

Answer 31

Classically activated, pro-inflammatory, and highly microbicidal

Question 32

M2 macrophages are:

Answer 32

Alternatively activated, associated with tissue repair, and can be exploited by pathogens

Question 33

What NK surface receptor recognizes stress molecules on infected/tumor cells?

Answer 33

Killer activation receptors (KAR)

Question 34

What NK surface receptor recognizes MHC I?

Answer 34

Killer inhibition receptors (KIR)

Question 35

# Clinical conditions: Chediak-Higashi Syndrome is caused by:

Answer 35

Defect in phagosome-lysosome fusion

Question 36

# Clinical condition: Chronic Granulomatous Disease (CGD) is caused by:

Answer 36

Defect in respiratory burst enzymes (reduced or no superoxide)

Question 37

# Clinical condition: IFN-y receptor deficiency leads to:

Answer 37

Impaired macrophage activation

Question 38

# Clinical condition: Leukocyte adhesion deficiency (LAD-1, LAD-2) results in:

Answer 38

Recurrent infections without pus formation, due to an inability of phagocytes to exit the bloodstream

Question 39

Why does C3 deficiency result in predisposition to severe infections?

Answer 39

Reduced opsonization of pathogens

Question 40

TLR3 recognizes:

Answer 40

Double stranded viral RNA