Inflammation I

Question 1

What is a common chemical defense mechanism between all epithelial surfaces in the body?

Answer 1

Presence of B-defensins

Question 2

What is inflammation?

Answer 2

A physiologic process by which vascularized tissues respond to injury

Has both soluble mediators and cellular components

Question 3

What are the hallmark signs of inflammation?

Answer 3

Redness, Swelling, Heat and Pain

Question 4

What is acute inflammation?

Answer 4

Rapid, shor lived (minutes to days) relatively uniform response

Characterized by the accumulation of fluid, plasma proteins, and neutrophils

Question 5

What is chronic inflammation?

Answer 5

Longer duration and includes all of acute response

Followed by the influx of lymphocytes, macrophages and possibly ending in fibroblast growth

May results in granuloma development

Question 6

What is the physiological response to tissue damage (cause of inflammation)?

Answer 6

Increased blood flow

Vascular permeability

Leukocyte migration into tissues and accumulation at the inflammatory foci

Activation of the leukocytes to destroy the foreign invader

Question 7

What are pathogen-associated molecular patterns?

Answer 7

Molecules associated with groups of pathogens, that are recognized by cells of the innate immune system

Recognized by toll-like receptors (TLRs) and other PRRs

Question 8

What is the plasma protease system?

Answer 8

Complement, kinins and clotting/fibrinolytic proteins

Initiated by bacteria through recognition of degraded bacterial cell wall products or toxins

Question 9

What do the endothelial cells do in response to inflammatory stimuli?

Answer 9

Contract, widening the gaps between the cells and permitting the passage of blood components

Question 10

What are defensins?

Answer 10

Pore forming proteins that are a part of the immediate response

Lyse pathogens

Question 11

What are kinins?

Answer 11

Serum proteases whose ultimate product is bradykinin, an agent known to induce smooth muscle contraction, vasoconstriction, and increased permeability of small blood vessels

Question 12

What are prostaglandins?

Answer 12

Oxidative derivative of fatty acid arachidonate that mediates fever, pain and vascular permeability

Question 13

What are leukotrienes?

Answer 13

inflammatory mediates derived from arachidonic acid that mediate vasoconstriction, increases vascular permeability

Endothelial adhesiveness and neutrophil chemotaxis

Question 14

What is histamine?

Answer 14

Vasoactive amine stored in mast cells and basophils

Promotes acute inflammation through increased vascular permeability

Question 15

What are neuropeptides?

Answer 15

Inflammatory mediators released by neurons in response to local tissue damage

Question 16

What are cytokines?

Answer 16

Molecules secreted by cells (leukocytes) that act locally in micro-environment by binding receptors on target cells

Question 17

What is IL-1?

Answer 17

Major inflammatory cytokine released by monocytes and activated macrophages

Increased blood flow, fever, enhanced expression of adhesion molecules, stimulation of cytokine production from other leukocytes

Question 18

What are TNF-alpha and TNF-beta?

Answer 18

Derived from macrophages

Similar actions to IL-1

Also induces apoptosis

Question 19

What is IL-4?

Answer 19

Activities related to allergic inflammation - basophil development and eosinophil chemotaxis

Participates in granuloma formation

Question 20

What is IL-6?

Answer 20

Released by T cells and endothelial cells

Promotes monocyte differentiation

Increases platelets in circulation and fibrinogen production by liver

Question 21

What is gamma interfueron?

Answer 21

Made by T cells and NK cells

Upregulates MHC proteins

Activates macrophages, making them more efficient killers

Question 22

What is IL-12?

Answer 22

Mad by macrophages and B cells

Stimulates proliferation of NK cells, T-helper and T-cytolytic cells

Question 23

What are opsonins?

Answer 23

Molecules that bind to bacterial surface molecules, making them more susceptible to phagocytosis

(e.g. C-reactive protein, mannose-binding lectin)

Question 24

What are some pyrogens and how do they exert their effect?

Answer 24

IL-1, IL-6, TNF-a, prostaglandins

Exert their effect via the temperature regulating function of the hypothalamus

Question 25

What are the three different complement pathways and their activating molecules?

Answer 25

Alternative - C3b

Lectin - Mannose-binding lectin

Classical - Antibody (IgM, IgG, IgA)

*All bind to microbial surface

Question 26

What common pathway do all three complement pathways converge on?

Answer 26

Activation of C3 and C5 convertases

Question 27

What are the functions of C3a and C5a fragments?

Answer 27

C3a and C5a are anaphylatoxins, C5a is a chemotaxin

Act on blood vessels to increase vascular permeability, allows fluid leakage and extravasation of proteins and monocytes and neutrophils

Question 28

What are the three phases of complement activation?

Answer 28

Recognition phase detects presence of infection

Enzymatic phase rapidly and extensively amplifies activation and promotes cellular inflammation and opsonization

MAC phase leads to damage of microbial membranes

Question 29

What are the components of the membrane attack complex?

Answer 29

C5b-C9

Question 30

What is the function of C3b?

Answer 30

Binds to CR1 on macrophages and promotes phagocytosis

Question 31

How does the complement promote the clearance of immune complexes from blood?

Answer 31

C3b binds CR1 on erythrocytes

C3b is deposited onto circulating immune complexes

RBCs bind CB3-immmune complex and carry them to the spleen

In the spleen/liver, macrophages strip off immune complexes and degrade them

Question 32

How do deficiencies in the complement system predispose an individual to infection?

Answer 32

Ineffective opsonization and defects in MAC

Defects in opsonization are more severe than defects in membrane attack complex