Innate and Adaptive Immunity

Question 1

Describe the term immunology

Answer 1

Resistance to pathogens based on the immune systems ability to recognize and clear foreign material. Ability of immune system to distinguish between self and non-self

Question 2

List 5 main leukocytes

Answer 2

1. Neutrophils
2. Eosinophils
3. Basophils
4. Lymphocytes
5. Monocytes-Macrophages

Question 3

List characteristics of neutrophils

Answer 3

1. Polymorphonuclear
2. Segemented
3. Part of innate immune system
4. Last about 10 hours in peripheral blood
5. Most abundant WBC in peripheral blood

Question 4

Describe neutrophil function

Answer 4

-Defends against bacteria and fungi
-Phagocytosis
-Promotes inflammatory response

Question 5

List characteristics of eosinophils

Answer 5

-Less phagocytic activity than PMN because no digestive enzymes
-3% of circulating leukocytes
-8 hr lifespan

Question 6

Describe eosinophil function

Answer 6

-kills parasites
-regulates inflammation
-associated with allergic reactions, drug reactions, certain skin orders, collagen vascular diseases, myeloproliferative disorderes, Hodgkin’s disease
-found in skin and mucosal barriers

Question 7

List basophil characteristics

Answer 7

-0.6% circulating leukocytes
-High concentrations of heparin (anticoagulant) and histamine in granules
-Immediate hypersensitivity reaction triggered from pollen, food, drugs, or insect venom

Question 8

Describe mast cells

Answer 8

-found in skin and mucosal barriers
-activated by microbial binding and complement components (innate or adaptive immunity can activate them)
-anaphylactic shock = severe reaction
-important defense against helminths and other pathogens

Question 9

List the granulocytes

Answer 9

Neutrophils
Eosinophils
Basophils
Mast cells

Question 10

List primary lymphoid tissues

Answer 10

1. Bone marrow (B cells mature here)
2. Thymus (T cells mature here)

Question 11

List secondary lymphoid tissues

Answer 11

1. Bone marrow (double dips)
2. Lymph nodes
3. Spleen
4. GALT
5. MALT
6. BALT
7. SALT (skin-associated)
8. Blood
9. Thoracic duct

Question 12

What does MPS stand for? Describe its traits

Answer 12

Mononuclear Phagocyte System

Cellular system that originates in the bone marrow and consists of monocytes, macrophages, and DCs. They maintain homeostasis, active innate immunity, and bridge innate and adaptive branches. Highly important in bolstering immunity against pathogens

Question 13

Describe traits of monocytes

Answer 13

-Produced in bone marrow
-4-6% circulating leukocytes
-largest normal leukocyte

Question 14

Describe life cycle of macrophages

Answer 14

-Consistent concentration produced at steady state
-Migrate into tissues without the presence of inflammation
-Can survive for many years after encountering pathogens

Question 15

Describe how macrophages kill pathogens

Answer 15

Phagocytosis and release of toxins and enzymes to directly kill pathogen

Question 16

Describe macrophage interaction with other immune components

Answer 16

-Recruit neutrophils to site of inflammation/infection by secreting soluble mediators called cytokines
-Respond to soluble mediators called interferons from adaptive immune system
-Present antigen to adaptive immune components (T cells)

Question 17

What are naive T and B cells?

Answer 17

Mature lymphocytes that have not encountered antigen yet

Question 18

Describe neutrophil interaction with other immune components and contrast with macrophages

Answer 18

-Neutrophils release chemokines to attract more neutrophils
-Respond to IL-17 from adaptive immune system
-Do not provide many signals to interact with adaptive immune system (macrophages do interact with adaptive immune system)

Question 19

Describe function of lymph nodes

Answer 19

They are lymphoid filters that transport lymphocytes to where they are needed. Lymph nodes respond to antigens

Question 20

Function of spleen?

Answer 20

Lymphatic filter that traps and concentrates foreign invaders. Major organ for clearance of particles. Important site of antibody production, particularly against bacteria

Question 21

Function of thoracic duct?

Answer 21

Rich source of mature T cells, so chronic drainage can cause T cell depletion. It transports lymphocytes to vena cava

Question 22

Function of GALT (gut-associated lymphoid tissue)?

Answer 22

Peyer’s patches located here (intestines) and the liver. Produces IgA and pre-B cells that go out into circulation after encountering antigen

Question 23

Function of BALT (bronchus-associated lymphoid tissue)?

Answer 23

In lower respiratory tract and hilar lymph nodes. Mainly associated with IgA production in response to inhaled antigens

Question 24

Skin-associated lymphoid tissue function?

Answer 24

Epidermal Langherhans cells present antigens. The cells interact with lymphocytes in the skin and lymph nodes

Question 25

Blood (as secondary lymphoid organ) function?

Answer 25

Circulate lymphocytes Mature T cells enough to produce graft vs host reaction Can use blood transfusions to induce acquired immunologic tolerance in kidney transplate patients Most frequently sampled lymphoid organ

Question 26

Describe lymph node structure

Answer 26

The cortex contains the germinal center of the secondary follicle is the site of mature B cell and is the site of clonal selection The paracortex is the site of mature T cells and is site of clonal selection The hilus is the entry/exit for Ab

Question 27

Function of secondary lymphoid organs?

Answer 27

Unique microenvironment for initiation and development of immune responses B and T cells make TNF (tumor necrosis factor) to form and maintain secondary organs

Question 28

Role of thymus in T cell maturation? What happens during maturation?

Answer 28

Thymus directs positive and negative selection of T cells. Positive selection involves checking if high CD3 expression present and if loosely bind self MHC antigen Negative selection marks T cells for apoptosis if they bind self-MHC Ag too tightly

Question 29

Describe B cell maturation

Answer 29

Starts and ends in bone marrow. Each B cell clone genetically mutates to generate different Ab

Question 30

What is the body's first line of defense?

Answer 30

Part of innate immune system. Feature biochemical (lysozyme, transferrin, lactic aci, earwax, sebum, acidic stomach,...) and anatomical defenses (skin, mucosa, cilia of respiratory tract, urinary and GI tracts)

Question 31

What is the body's second line of defense?

Answer 31

Part of innate immune system. Features innate immune cells and antimicrobial proteins (cytokines, chemokines, interferons, complement)

Question 32

What is the body's third line of defense?

Answer 32

The adaptive immune system (humoral + cellular)

Question 33

Compare innate and adaptive immunity

Answer 33

Innate: First to respond. Does not require memory. Specific against molecules shared by groups of related microbes and molecules secreted by damaged cells. Blood proteins are complement. Adaptive: Slower to respond due to priming and development of memory. Second time of infection though, acts super fast and more robustly. Specific to antigens it developed memory for. Blood proteins are antibodies.

Question 34

Describe time frames of innate immediate immunity

Answer 34

First 0-4 hours. Antimicrobial proteins first to respond to remove infectious agent

Question 35

Describe time frames of early induced immunity for innate immune system

Answer 35

4-96 hours. PAMPs recruit phagocytes and other innate immune cells and remove infectious agent

Question 36

Time frame of adaptive immunity?

Answer 36

3-5 days. Naive lymphocytes recognize and bind Ag and undergo clonal expansion into effector cells. Memory developed and remove infectious agent