Innate Immunity

Question 1

3 groups of lymphoid organs

Answer 1

Sources of lymphocytes
Sites of lymphocyte development
Sites where lymphocytes respond to antigens

Question 2

Sources of lymphocytes

Answer 2

Yolk sac
Fetal liver
Bone marrow

Question 3

Primary Lymphoid Organs (sites of lymphocyte development)

Answer 3

Thymus
Bursa
Peyer’s patches
Bone marrow

*No recognition of antigens

Question 4

Secondary Lymphoid Organs (sites where lymphocytes respond to antigens)

Answer 4

Tonsils
Spleen
Lymph Nodes
Peyer's patches
Bone marrow

*Recognition of antigens

Question 5

Major Lymphoid Tissues

Answer 5

Bone marrow
Spleen
Lymph Nodes
Urogenital System
Intestine
Mammary Glands
Respiratory Tract
Salivary Glands
Thymus

Question 6

Time of development Primary vs Secondary lymphoid organs

Answer 6

Primary: early embryonic life

Secondary: Late fetal life

Question 7

Persistence of primary vs secondary lymphoid organs

Answer 7

Primary: involutes after puberty

Secondary: Persists in adults

Question 8

Effect of removal of primary vs secondary lymphoid organs

Answer 8

Primary: Loss of lymphocytes

Secondary: No/minor effects

Question 9

Congenital athymic animals

Answer 9

Have no thymus - hairless mouse and dog.

Skin grafts on mice were all successful due to no immune response to reject foreign material.

Question 10

System of open ended vessels that return extravascular fluid from the periphery to the blood.

Answer 10

Lymphatics

Lymph nodes are filtering stations

Question 11

Lymphocyte recirculation

Answer 11

Immune surveillance - waiting for pathogens to arrive so immune response can be initiated

Question 12

What is the first line of immune response (non-specific)?

Answer 12

Innate immunity (cellular and humoral)

Question 13

What is the second line of immune response (specific)?

Answer 13

Adaptive immunity (cellular and humoral)

Question 14

Physical barriers are part of what type of immunity?

Answer 14

Innate (non specific)

Question 15

Systems with physical barriers

Answer 15

Repro: low pH
Intestinal: pH, mucus, lysozyme, defensins, bile acids
Skin: keratinized, fatty acids, dessication
Urinary: unidirectional flushing
Mammary: Flushing, lysozyme, complement, lactoferrin
Eye: physical flushing, lysozyme
Trachea: mucus, cilia, cough
URT: trap/remove particles in mucus

Question 16

What is the Complement System?

Answer 16

Collection of 30 different plasma proteins that are individually inert, but interact to create powerful immune response.

Heat-labile serum factor

10% of total serum proteins

Question 17

What activates the complement system?

Answer 17

Pathogen Associated Molecular Patterns (PAMPs)
or
Ag-Ab complex.

Question 18

What are the 3 pathways of complement activation?

Answer 18

Classical (antibody dependent) (Ag-Ab)
Alternative
Lectin

Question 19

All 3 pathways of complement activation lead to what?

Answer 19

Activation of C3 and generation of C5 convertase

Activation of C5

Membrane Attack Complex (MAC)

Question 20

How does innate immune system recognize microorganisms?

Answer 20

Characteristic structures not present on mammalian cells

Microbial products essential for survival of microbes

Question 21

What are PAMPs and MAMPs?

Answer 21

Pathogen Associated Molecular Patterns
Microbe Associated Molecular Patterns

Allow innate immune cells to recognize pathogens in the system

Question 22

Examples of PAMPs

Answer 22

Peptidoglycan in bacterial cell wall
Pilin protein
Unmethylated DNA 
Lipotechoic acids and lipoproteins
Capsule polysaccharides 
Flagellin protein

Question 23

Examples of Pattern Recognition receptors

Answer 23

Neutrophils
Macrophages
Dendritic cells

*Phagocytosis or Endocytosis of microbes

Question 24

What are DAMPs?

Answer 24

Damage Associated Molecular Patterns

*Macrophage can recognize cytoplasmic release from cell and know it is infected

Question 25

What activates macrophages?

Answer 25

DAMPs and PAMPs