Inflammation and Immune Response

Question 1

What are some features of innate immunity?

Answer 1

Is the first line of defence, inborn, distinguishes self from non-self, however, unable to distinguish between pathogens

Question 2

What are some of the components of innate immunity?

Answer 2

Epithelial cells
Neutrophils and macrophages
NK cells
Complement proteins
Cytokines

Question 3

What are the components of adaptive immunity?

Answer 3

B and T lymphocytes

Question 4

What is the humoral response?

Answer 4

(part of adaptive immunity) Results in the production of antibodies directed against an antigen. Involve B lymphocytes

Question 5

What is the cell-mediated response?

Answer 5

(part of adaptive immunity) Leads to the destruction of infected body cells, include cytotoxic and helper T cells

Question 6

What are the central immune structures?

Answer 6

Bone marrow and thymus. Where immune cells are produced and mature

Question 7

What are the peripheral immune structures?

Answer 7

Lymph nodes, spleen. Where immune cells interact with antigens

Question 8

What kind of cells are CD4+?

Answer 8

Helper T cells

Question 9

What kind of cells are CD8+?

Answer 9

Cytotoxic T cells

Question 10

What does CD stand for?

Answer 10

Clusters of differentiation

Question 11

What is the difference between NK cells and cytotoxic T cells?

Answer 11

NK cells do not need to recognise a specific antigen before being activated, they are programmed to automatically kill foreign cells.
Cytotoxic T cells have to be activated by a specific antigen in order to become cytotoxic

Question 12

What does MHC I do?

Answer 12

Allows the body to differentiate between normal and infected cells. Expressed on almost all cells

Question 13

What does MHC II do?

Answer 13

Allows appropriate interactions among immune cells. Expressed only on a few cell types including macrophages, B cells, helper T cells

Question 14

What are cytokines?

Answer 14

Are proteins that form a communication link between immune cells and other tissues and organs of the body

Question 15

What cells do cytokines primarily act on?

Answer 15

Activated helper T cells and macrophages

Question 16

Why are cytokines secreted for only a brief time?

Answer 16

This ensures that excessive immune responses do not occur

Question 17

What can excessive production of cytokines lead to?

Answer 17

Serious adverse effects such as septic shock and some kinds of cancer

Question 18

What is a complement?

Answer 18

A group of proteins that circulate in the blood and, when activated, bind and destroy any foreign cell

Question 19

What does the complement system do?

Answer 19

Mediates innate and adaptive immunity and therefore enables the body to produces an inflammatory response, lyse foreign cells, and increase phagocytosis

Question 20

How is complement controlled?

Answer 20

Uncontrolled activation is prevented by inhibitor proteins, which prevent the membrane attack complex from forming, and the instability of the activated proteins

Question 21

What is the result of inadequate immune response?

Answer 21

Immunodeficiency

Question 22

What is the result of excessive immune response?

Answer 22

Allergic reactions and/or autoimmune diseases

Question 23

How are normal responses self-limited?

Answer 23

Antigen elimination, the products of response (eg cytokines and antibodies) having a short life span and being secreted for brief periods after antigen recognition

Question 24

What is tolerance?

Answer 24

An aspect of self-regulation, is the ability of the immune system to be non-reactive to self-antigens (ie protects an individual from harmful autoimmune responses)

Question 25

What are the characteristics of acute inflammation?

Answer 25

Short duration, characterised by the exudation of fluid and plasma components, and emigration of neutrophils into extravascular tissues

Question 26

What are the characteristics of chronic inflammation?

Answer 26

Longer duration, associated with the presence of lymphocytes and macrophages, proliferation of blood vessels, fibrosis and tissue necrosis

Question 27

What are the stages of acute inflammation?

Answer 27

Immediate vascular changes, influx of inflammatory cells, widespread effects of inflammatory mediators

Question 28

Explain the immediate vascular changes (acute inflammation)

Answer 28

Initiated by brief vasoconstriction of small blood vessels, followed by vasodilation of the arterioles and venules that supply the area
Results in the area becoming congested causing redness (erythema) and warmth

Question 29

Explain the influx of inflammatory cells in acute inflammation

Answer 29

eg neutrophils from the microcirculation and their activation to eliminate the injurious agent
Done by the means of phagocytosis and the release of enzymes by neutrophils and macrophages

Question 30

Explain acute inflammation in terms of inflammatory mediators

Answer 30

Produces a fever and other systemic signs and symptoms
Plasma-derived mediators for increasing vascular permeability
Cell-derived mediators for increasing vascular permeability, vasodilation, pain, fever, etc

Question 31

What are the two type of chronic inflammation?

Answer 31

Non-specific chronic inflammation and granulomatous inflammation

Question 32

Explain non-specific chronic inflammation

Answer 32

Involves accumulation of macrophages and lymphocytes at the site of injury
Macrophages infiltrate the inflamed site and accumulate, therefore, leading to fibroblast proliferation with subsequent scar formation which replaces the normal connective tissue of the involved structures

Question 33

Explain granulomatous inflammation

Answer 33

Involves formation of granulomas (1-2mm lesions) in which there is a massing of macrophages surround by lymphocytes
These modified macrophages aka epitheloid cells
They can clump in a mass, forming a multinucleated giant cell that attempts to surround the foreign agent
Dense membrane of connective tissue encapsulates and isolates the lesion

Question 34

What is granulomatous inflammation associated with?

Answer 34

Asbestos, silica, and microorganisms causing TB, syphilis etc, all of which are poorly digested and not easily controlled by other inflammatory mechanisms