23 Overview of the immune system

Question 1

Generated from gene rearrangement. These receptors are specific for one antigen

Answer 1

Somatically generated receptors

Question 2

non-specific cells of the innate immune response. These receptors recognize families of patterns that are found in certain microorganisms and not in the human body

Answer 2

Pattern recognition receptors

Question 3

soluble proteins located on cell surfaces. Identify pathogens

Answer 3

Pathogen receptors

Question 4

o Physical barrier:
 First line of defense against microbes.
 Skin, musuc, membranes lining the organs (large perimeter)
o Innate immune system:
 Second line of defense
 Eliminate microorganisms and can prevent infection
 If elimination of the infection is impossible, the innate immune system will alert the adaptive immune system of the problem and recruit an adaptive immune response
o Adaptive immune system:
 Third line of defense
 Specificity, diversity, and memory

Answer 4

Three main lines of defense of the immune system

Question 5

Kill the microorganism by inducing apoptosis. Uses pattern recognition receptors (non-specific)

Answer 5

NK cells

Question 6

The main phagocytic cells of the innate immune system

Answer 6

Macrophages and neutrophils

Question 7

24 hours after the initiation of infection. This branch of the immune system is activated

Answer 7

Adaptive immune response

Question 8

These cells produce antibodies

Answer 8

B lymphocytes

Question 9

These cells help coordinate the immune response

Answer 9

T lymphocytes

Question 10

• Specificity: For molecules shared by groups of related microbes and molecules produced by damaged host cells
• Diversity: Limited, germline encoded
• Memory: none

Answer 10

Innate immunity

Question 11

• Specificity: specific for any particular pathogen that has been identified (microbial and nonmicrobial antigens)
• Diversity: very large, receptors are produced by somatic recombination of gene segments
• Memory: Yes

Answer 11

Adaptive immunity

Question 12

Review all diagrams

Answer 12

Do it

Question 13

aka granulocytes. These are the neutrophils, basophils, and eosinophils

Answer 13

Polymorphonuclear leukocytes

Question 14

Most abundant leukocyte in blood. Major function is phagocytosis

Answer 14

Neutrophils

Question 15

Participate in destruction of pathogens that are too big to be phagocytosed by neutrophils or macrophages. These cells release granules that kill the microorganism

Answer 15

Eosinophils & basophils

Question 16

Contain IgE receptors. These IgE receptors trigger the allergic response when an allergen is encountered for the second time

Answer 16

Eosinophils, basophils, and mast cells

Question 17

Neutralize the pathogen, preventing infection. ___ do NOT kill microbes. The ___ do however enable the microbe to be identified by phagocytic and Natural Killer cells for destruction

Answer 17

Antibodies

Question 18

Orchestrate the immune response. Determine which immune cells will be activated (macrophages, phagocytic cells to induce inflammation, induction of proliferation and differentiation of T cells and B cells)

Answer 18

T helper lymphocytes

Question 19

Induces apoptosis of an infected cell of the human body that is expressing a microbial antigen. Specific for a particular antigen

Answer 19

Cytotoxic T cell

Question 20

Regulate the immune response. Mainly by suppressing the immune response

Answer 20

Regulatory T lymphocytes

Question 21

Mainly performed by B cells (that create antibodies)

Answer 21

Humoral immunity

Question 22

Mainly performed by T helper cells and cytotoxic T lymphocytes

Answer 22

Cell-mediated immunity

Question 23

Molecules (antigens) that are able to generate an immune response

Answer 23

Immunogens

Question 24

1) Foreignness
2) Molecular size: Larger molecules mount a larger immune response than smaller molecules (they are visualized more easily by the immune system)
3) Chemical-structural complexity: Complex structures mount stronger immune responses
4) Dosage, route, and timing of antigen administration: If the antigen comes via a route that is designed to mount an immune response, the response will be higher. Ex: an antigen entering the respiratory tract as supposed to an antigen being injected directly into the bloodstream
5) Antigenic determinants (epitopes)
o Epitopes: Small chemical groups on the antigen molecule that can elicit and react with an antibody. An antigen can have one or more epitopes
o Adjuvants: Not an immunogen. They are chemically unrelated to the immunogen, and are not covalently bound to it. Adjuvants enhance the immune response to an immunogen.

Answer 24

Characteristics of an immunogen

Question 25

A small molecule that can elicit an immune response only when attached to a large carrier such as a carrier protein. The carrier may be one that also does not elicit an immune response by itself (however, the combination does elicit an immune response. This is because in general, only large molecules, infectious agents, or insoluble foreign matter can elicit an immune response in the body)
• Antibodies that are produced can now react to either the ___ or the carrier protein individually

Answer 25

Hapten

Question 26

T/F. Over-excited lymphocytes are destroyed in the bone marrow before they can mature and spread to the peripheral lymph nodes. This is b/c an easily excitable lymphocyte is likely to destroy cells of the human body that are not infected

Answer 26

True

Question 27

 Specificity: Ensures that the immune response to a microbe (or nonmicrobial antigen) is targeted to that microbe (or antigen)
 Diversity: Enables the immune system to respond to a large variety of antigens
 Clonal expansion: Increase in the number of antigen-specific lymphocytes to keep pace with microbes
 Memory: Increases the ability to combat repeat infections by the same microbe
• Effector cells and memory cells (longer half-life) are produced when a B cell encounters a pathogen. The secondary immune response is more robust than the primary immune response
 Nonreactivity to self: Prevents injury to host during responses to foreign antibodies
• Over-excited lymphocytes are destroyed in the bone marrow before they can mature and spread to the peripheral lymph nodes. This is b/c an easily excitable lymphocyte is likely to destroy cells of the human body that are not infected
 Specialization: Generates responses that are optimal for defense against different types of microbes
 Contraction and homeostasis: Allows immune system to recover from one response so that it can effectively respond to newly encountered antigens

Answer 27

Cardinal features of the adaptive immune system

Question 28

are a large and heterogeneous group of secreted proteins produced by many different cell types, mediate and regulate all aspects of innate and adaptive immunity

Answer 28

Cytokines

Question 29

The organs in which lymphocytes are generated and mature

Answer 29

Primary lymphoid organs

Question 30

Production and maturation of immune cells occurs here

Answer 30

Bone marrow

Question 31

Maturation of T cells occurs here

Answer 31

Thymus

Question 32

The organs in which lymphocytes interact with antigens. Antigens are presented to the lymphocytes from the tissues by circulating antigen presenting cells (macrophages & dendritic cells)

Answer 32

Secondary lymphoid organs

Question 33

(Primary or secondary lymphoid organs?) Lymph nodes & spleen

Answer 33

Secondary lymphoid organs

Question 34

Collects lymph (fluid) from the tissues into lymphatic vessels, and recycles the lymph back to the blood

Answer 34

Lymphatic system

Question 35

) is conferred by a host response to a microbe or microbial antigen, whereas passive immunity is conferred by adaptive transfer of antibodies or T lymphocytes specific for the microbe
o Provides resistence to infection and is specific for microbial antigens
o Only the active immune responses generate memory
o Cell transfers can be done only between genetically identical donor and recipient to avoid rejection of the transferred cells

Answer 35

Active immunity

Question 36

Dysregulated or uncontrolled, excessive, immune response (can be caused by response to foreign bodies or by response to self-antigen autoimmunity)

Answer 36

Hypersensitivity reactions