Primers in Immunology: Major Concepts of Host Defense

Question 1

Immune system appropriate response examples

Answer 1

Destruction of cancer cells

Destruction of infectious organisms

Question 2

Immune system inappropriate response examples

Answer 2

Allergy and hypersensitivity
Transplant rejection
Immunodeficiency
Autoimmune

Question 3

4 Pathogenic organisms

Answer 3

Virus
Bacterial
Protozoa
Worms

Question 4

Fixed elements of immune system

Answer 4

Lymphoid organs

• bone marrow (primary)
• thymus (primary)
• spleen and lymph nodes
• mucosal immune tissue

Question 5

Mobile elements of immune system

Answer 5

cells derived from the bone marrow

soluble (humoral) components

Question 6

Innate (natural) responses

Answer 6

occur to the same extent every time infectious agent is encountered

• rapid response - minutes to hours
• relatively nonspecific - recognizes pathogens but doesn’t distinguish
• no memory

Question 7

Acquired (adaptive) responses

Answer 7

improve on repeated exposure to a given infection

• slow response - days to weeks
• specific - tailored for particular pathogen (Ag)
• has memory - response is greater upon repeated exposure

Question 8

Non-phagocytic cells

Answer 8

Only release inflammatory mediators

• Basophils
• mast cells
• eosinophils
• natural killer (NK) cells

Question 9

Phagocytic cells

Answer 9

Immune cells capable of phagocytosis
Also release inflammatory mediators
-neutrophils
-monocytes
-macrophages

Question 10

Neutrophils

Answer 10

the most abundant circulating white blood cells capable of phagocytizing and digesting microbes

Question 11

Monocytes

Answer 11

circulating white blood cells which are precursor cells for tissue macrophages

Question 12

Macrophages

Answer 12

tissue residing phagocytic cells derived from monocytes. Infection-activated macrophages phagocytize and kill pathogens and secrete inflammatory mediators

Question 13

Basophils

Answer 13

blood circulating granulocytes which may contribute to immediate hypersensitivity runs (allergy)

Question 14

Mast cells

Answer 14

tissue residing cells involved in allergic reactions. Contain numerous granules filled with inflammatory mediators which being released trigger the immediate hypersensitivity rxns

Question 15

Eosinophils

Answer 15

defense against extracellular parasites

-contribute to allergic diseases (late phase rxns)

Question 16

NK Cells

Answer 16

subset of lymphocytes involved in innate responses

-recognize and kill abnormal cells such virus-infected cells or tumor cells

Question 17

Complement

Answer 17

a system of serum and cell surface proteins which upon activation generate an important defense mechanism. Activation of Complement results in a cascade of enzymatic reactions that produce inflammatory mediators and opsonins

Question 18

Acute-phase proteins

Answer 18

plasma proteins which concentration is increased in response to inflammation
Ex. C-reactive protein

Question 19

Cytokines

Answer 19

A large family of low-molecular weight soluble proteins involved in regulating cellular activity

Question 20

Chemokines

Answer 20

chemotactin cytokines that regulate the transit of leukocytes from blood into tissues

Question 21

Antigen (Ag)

Answer 21

any molecule that provokes an immune response

Question 22

Acquired immunity

Answer 22

involves proliferation of antigen-specific B and T cells

-occurs when the surface receptors of these cells bind to antigens

Question 23

Antibody (Ab)

Answer 23

a type of protein molecule that is also called immunoglobulin
-produced by B cells and exhibits a high degree of specificity to Ag

Question 24

T cell Receptor (TCR)

Answer 24

an antigen receptor on cell membrane of T lymphocytes that recognize foreign peptides presented by Ag-presenting cells

Question 25

Cells involved in acquired immune responses

Answer 25

APC B cells T cells

Question 26

Antigen presenting cells

Answer 26

(APC) | display the antigen to lymphocytes and collaborate with them in the response to the antigen

Question 27

B cells

Answer 27

secrete immunoglobulins, the antigen-specific antibodies responsible for eliminating extracellular microorganisms

Question 28

T cells

Answer 28

the cell type that mediates cell-mediated immune response of adaptive immunity. T cells are matured in the thymus and circulate in blood. Once activated by specific antigen, T cells are recruited to a peripheral site

Question 29

2 Cell types central to adaptive immune response

Answer 29

T and B lymphocytes

Question 30

Phase I immune system

Answer 30

0-4 hours Non-induced innate/non-specific response -preformed defenses (skin barrier, pH, saliva proteases)

Question 31

Phase II immune system

Answer 31

4-96 hours Induced innate/broadly specific response -phagocytosis, complement activation, other inflammatory mechanism, cytokine secretion

Question 32

Phase III Immune system

Answer 32

> 96 hours Induced adaptive/highly specific response -B cells (Ab), helper T cells, cytolytic T cells

Question 33

Developed germ theory

Answer 33

Koch

Question 34

Practice of vaccination and variolization

Answer 34

Jenner

Question 35

Gram positive bacteria

Answer 35

Have large layer of peptidoglycan

Question 36

Gram negative bacteria

Answer 36

Single layer of peptidoglycan | LPS

Question 37

Cell-mediated defense deals with _______ pathogens

Answer 37

Intracellular

Question 38

Antibody mediated defense deals with ______ pathogens

Answer 38

Extracellular

Question 39

Viruses

Answer 39

Immune response is dependent on location | At some stage, will express viral antigens that will be recognized and destroyed