Chapter 6 Specific Host Defense Mechanism

Question 1

scientific study of the immune system and immune response

Answer 1

immunology

Question 2

a condition of being immune or resistant to a particular infectious disease

Answer 2

immunity

Question 3

Categories of Host Defense Mechanisms

always involves the production of antibodies

Answer 3

humoral immunity

Question 4

Categories of Host Defense Mechanisms

involves many different cell types, including macrophages, T helper cells, cytotoxic T cells, natural killer cells, killer cells and granulocytes

Answer 4

cell-mediated immunity

Question 5

immunity results from the active production or receipt of antibodies during one’s lifetime

Answer 5

acquired immunity

Question 6

the process of exposing the body to an antigen to generate an adaptive immune response; the response takes days/weeks to develop but may be long lasting/ life time

Answer 6

active acquired immunity

Question 7

the process of providing IgG antibodies to protect against infection; it gives immediate but short-lived protection - several weeks 3 to 5 months at most

Answer 7

passive acquired immunity

Question 8

immunity that is acquired in response to the entry of a live pathogen into the body (in response to an actual infection)

Answer 8

natural active acquired immunity

Question 9

immunity that is acquired in response to vaccines

Answer 9

artificial active acquired immunity

Question 10

the immunity that is acquired by a fetus when it receives maternal antibodies

Answer 10

natural passive acquired immunity

Question 11

immunity that is acquired when a person receives antibodies contained in antisera or gamma globulin

Answer 11

artificial passive acquired immunity

Question 12

the material that can artificially induce immunity to an infectious disease, usually after injection or, in some cases, ingestion of the material

Answer 12

vaccines

Question 13

An ideal Vaccine is on that:

• contains antigenic determinants to stimulate the immune system to _ (antibodies that will protect individuals from infection by the pathogen)
• contains antigenic determinants from ____ that cause disease, such as vaccines are referred to as multivalent or polyvalent
• has few (preferably, no) side effects
• does not cause disease in the person

Answer 13

produced protective antibodies

all the strains of the pathogens

Question 14

How does vaccine works?

Vaccines stimulate the recipient’s immune system to produce _____

The protective antibodies or memory cells produced in response to the vaccine then remain in the recipient’s body to do battle with a particular pathogen, should that pathogen enter the recipient’s body at some time in the future, body becomes ready

Answer 14

protective antibodies

Question 15

Humoral Immunity

_ are foreign organic substances that are large enough to stimulate the production of antibodies; antibody – generating substance

Answer 15

antigens

Question 16

Substances that are capable of stimulating the production of antibodies

Answer 16

antigenic

Question 17

Antibodies are proteins produced by ____ in response to the presence of an antigen.

Usually, an antibody is ____ in that it will recognize and bind to only to the antigenic determinants that stimulated its production.

The term antibodies refer to ____ with particular specificity for an antigen

Answer 17

lymphocytes

specific

immunoglobulins

Question 18

Where do Immune Response Occur?

Antigens in the:
* Blood -
* Tissues -
* Mucosal surfaces -

Answer 18

• spleen
• lymph nodes
• mucosa-associated lymphoid tissues

Question 19

What do antibodies do to fight pathogens?

• ____ via blocking or antibody-dependent cellular toxicity
• ____ compliment dependent cytotoxicity
• ____ opsonization and phagocytosis

Answer 19

• neutralization of infectious agents
• activation of the complement system
• binding of foreign substances to be destroyed

Question 20

Cell-mediated Immunity

T cells rely on antigen-presenting cell that contain membrane-bound MHC (major histocompatibility complex) class I proteins in order to ____

the binding specificity between MHC proteins and foreign antigens in essential for the ____ of naïve T cells into helper or killer T cells

With the assistance of MHC class I proteins, T cells can also recognize ____ cells

Answer 20

recognize intracellular target antigens

maturation and differentiation

cancerous

Question 21

Cell-mediated Immunity

What lymphocytes are involved in cell-mediated immunity?

Answer 21

helper T cells, killer T cells, and macrophages

• when a “helper” T cells finds an antigen-presenting cell in the body, it releases a set of signaling proteins called cytokines
• these cytokines activated “killer” T cells and macrophages to move to the site of interest in order to destroy the antigen-presenting cell/s

Question 22

results when as person’s immune system no longer recognizes certain body tissues as self and attempts to destroy those tissues as if they were non-self or foreign

-this may occurs with certain tissues that are not exposed to the immune system during fatal development

Answer 22

Autoimmune Diseases

Question 23

-if a person’s immune system is functioning properly, that person is said to be ___

Answer 23

immunocompetent person

Question 24

• Ways in which the body protects itself from pathogens
• Can be thought of as an army consisting of three lines of defense

Answer 24

HOST DEFENSE MECHANISMS

Question 25

Non-specific Defences

Answer 25

Innate Immunity

Question 26

Adaptive Immunity

Answer 26

Specific Defences

Question 27

# Non-specific Defences (Innate Immunity) First line of Defense

Answer 27

- Skin - Mucous membranes - Secretions of skin and mucous membranes

Question 28

# Non-specific Defences (Innate Immunity) Second line of Defence

Answer 28

- Phagocytic leukocytes - Antimicrobial proteins - Inflammatory response - Fever

Question 29

# Specific Defences (Adaptive Immunity) Third line of Defence

Answer 29

- Lymphocytes - Antibody - Memory cells

Question 30

# Host Defense Mechanisms In the third line of defense, special proteins called ____ are usually produced in the body in response to the presence of foreign substances called antigens.

Answer 30

antibodies

Question 31

General and serve to protect the body against many harmful substances ## Footnote innate or inherited resistance (natural resistance) makes some people and animals more resistant to some diseases

Answer 31

Nonspecific Host Defense Mechanisms

Question 32

serves as a nonspecific host defense mechanism by flushing organisms from the pores and the surface of the skin ## Footnote * also contains the enzyme, lysozyme, which degrades peptidoglycan in the bacterial cells (especially Gram-positive bacteria)

Answer 32

Perspiration

Question 33

is a protein that binds iron, a mineral that are **required by all pathogens**

Answer 33

Lactoferrin

Question 34

is an enzyme that produces superoxide radicals, highly reactive forms of oxygen, which are **toxic to bacteria**

Answer 34

Lactoperoxidase

Question 35

Factors protect the digestive system from bacterial colonization

Answer 35

-Digestive Enzymes -Acidity of the stomach (approximately pH 1.5) -Alkalinity of the intestines

Question 36

is an interaction where resident microbes of the indigenous microflora **prevent the colonization of new arrivals** to a particular anatomical site.

Answer 36

Microbial Antagonism

Question 37

Factors that attributes to the inhibitory capability of indigenous microflora:

Answer 37

-Competition for colonization sites -Competition for nutrients -Production of substances that kill other bacteria

Question 38

Cell involves in the Second Line of Defence

Answer 38

* Neutrophils * T helper cells * Cytotoxic (killer) T cells * Macrophages * Dendritic cells * B cells * Suppressor T cells

Question 39

* -General purpose phagocytes * -These cells primarily attack bacteria. They are dispensable rather like pawns on a chessboard. * -They rush to the site of incoming bacteria to fight them, but are easily killed.

Answer 39

Neutrophils ## Footnote * only last a few days in the body (before they self-destruct), but our bone marrow produced more everyday. Some bacteria avoid neutrophils by hiding inside cells

Question 40

* These cells are like the bosses. * Each T helper cell only looks out for one type * Many T helper cells are needed to watch for many different diseases or invaders

Answer 40

T helper cells ## Footnote * They give instructions to other cells by producing signals.

Question 41

* These are killer cells * They punch holes in the walls of the pathogen cell so that the contents ooze out.

Answer 41

Cytotoxic (killer) T cells

Question 42

* means ‘big eater’ * These cells “eat” (ingest) or clean up the mess of dead cells

Answer 42

Macrophages

Question 43

-These cells are like the spies. -They notice if there is an invader and then present evidence of the invader to T cells in the ____

Answer 43

Dendritic cells lymph nodes

Question 44

* These **produce antibodies**, which lock onto the antigen of invading bacteria and immobilize them until the macrophage consumes them * some of them become memory cells after being activated by the presence of antigen * These cells are able to live for a long time and can respond quickly following a second exposure to the same antigen

Answer 44

B cells

Question 45

* When the infection is gone, the immune system needs to be calmed down (or the killer cells may keep killing) -These cells **slow down or turn off the immune system** to prevent damage to good cells

Answer 45

Suppressor T cells

Question 46

* The **lymphatic system** is a system of thin tubes that runs throughout the body. These tubes are called **lymph vessels**. They contain lymph. * Lymph is **fluid** in which ____ cells are found.

Answer 46

white blood (immune)

Question 47

* Lymph nodes are small, round masses of tissue that are found in certain areas (such as the neck, groin and armpits). They ____ bacteria and other foreign materials out of lymph and expose them to B and T cells and macrophages that can engulf them. * These cells multiply in response to accumulation of such materials, which is why lymph nodes ____ during infections.

Answer 47

filter swell

Question 48

# . -A glycoprotein synthesized in the liver, has a high affinity for iron -It functions to store and delivered iron to the host cells

Answer 48

Transferrin

Question 49

Substances that stimulate the production of fever is called ____ which may originate either outside or inside the body.

Answer 49

pyrogens or pyrogenic substance

Question 50

is an example of pyrogen that is produced within the body (endogenous pyrogen)

Answer 50

Interleukin I (IL – 1)

Question 51

Fever augment is Host defense:

Answer 51

* -By stimulating WBC to deploy and destroy invaders * -By reducing the plasma iron * -By inducing the production of IL – 1 (causes the proliferation, maturation, and activation of lymphocytes in the immunologic response)

Question 52

Benefits Fever

Answer 52

-Inhibits the multiplication of temperature-sensitive microorganisms -Impedes the nutrition of bacteria by reducing the availability of iron -Increases metabolism and stimulates immune reaction and naturally protective physiological process

Question 53

Small, antiviral proteins produced by virus infected cells. -Three known types alpha (α), beta (β), and gamma(γ) ____, are induce by different stimuli and produced by different cells.

Answer 53

interferon/s

Question 54

localized physical condition in which part of the body becomes reddened, swollen, hot, and often painful, especially as a reaction to injury or infection

Answer 54

Inflammation

Question 55

Major Events

Answer 55

- Vasodilation - increased permeability of the capillaries (allowing the escape of plasma and plasm proteins) - Egress of leukocytes from the capillaries and their accumulation at the site

Question 56

Purpose of inflammation

Answer 56

-localized an infection -prevent the spread of the microbial infection -neutralized any toxins -aid in the repair of damaged tissue

Question 57

Phagocytosis begin when phagocytes move to the site where they are needed. This directed migration is called chemotaxis results of chemical attractants called ____ .

Answer 57

hemotactic agent

Question 58

How does it work? 1/ -When a pathogen (disease-causing organism) invades the body, the **neutrophils** ____ and try to engulf it and destroy it. -Should the invaders get past the neutrophils, several things may happen.

Answer 58

gather at the entry site

Question 59

How does it work? 2/ The **macrophages** (big eaters) will be attracted by the ____ those of the neutrophils. These cells attempt to engulf the invader, but they also send signals to other cells for help.

Answer 59

death

Question 60

How does it work? 3/ The **dendritic cells**, which are constantly scouting around (they can communicate with up to 200 other cells at once) may find the pathogen and ____ to T helper cells that congregate in the lymph nodes in the body.

Answer 60

take a piece to present

Question 61

How does it work? 4/ - A **T helper cell** will recognize only one pathogen. If the T helper cell recognizes the invader, it will immediately ____ to increase numbers. - The T helper cell then activates the appropriate immune cells for the attack. - if the invading organism is a ____, the T helper cell will signal the **cytotoxic (killer) T cells** to come to the rescue. These cells punch holes in the walls of invading virus-infected host cells, killing the cells and destroying the virus.

Answer 61

clone virus

Question 62

How does it work? 5/ - **B cells** can also be activated to produce antibodies that will stick to free invaders, ____ - If the invader is ____, B cells are usually drawn to the task. They squirt an antibody (IgG) onto the bacteria (a bit like squirting tomato sauce onto chips) * This sticks everything together and makes it attractive to macrophages, which clear up the mess. - If the bacteria enters the system through the gut, the antibodies released by the B cells are usually IgA antibodies. - These antibodies acts by blocking the bacteria adhering to the gut cells, preventing infection

Answer 62

marking them out for macrophages to clean up. bacterial

Question 63

How does it work? 6/ After a few days of fighting off the pathogen, you will recover from your infection. At this stage, the immune system activates **T suppressor cells**. These cells send out ‘calm down’ signals, which ____ the immune system.

Answer 63

quieten down