Lecture 15

Question 1

What are the exocrine glands involved in the mucosal system?

Answer 1

lacrimal glands, salivary glands, and lactating breasts

Question 2

The vast majority of infectious agents invade the human body via _______ ______.

Answer 2

mucosal routes

Question 3

Name two non-pathogenic antigens?

Answer 3

food proteins and commensal microorganisms

Question 4

What is the basic structure of mucins?

Answer 4

gigantic glycoproteins

Question 5

Name at least one way mucins protect epithelial surfaces.

Answer 5

• extensive glycosylation keeps mucous hydrated
• binds secretory IgA and defensins to help trap/kill bacteria

Question 6

Name at least one way that commensal microorganisms help the gut maintain its health.

Answer 6

• synthesizes essential metabolites like vitamin K
• breaks down plant fibers
• inactivate toxic substances
• compete with pathogens for space and nutrients
• interact with epithelium to trigger secondary lymph tissue

Question 7

What is the purpose of villi in the gut wall?

Answer 7

to increase surface area

Question 8

What does the lamina propria in the gut wall contain?

Answer 8

immune cells

Question 9

What is in a peyer’s patch/what is its function?

Answer 9

Peyer’s patches contain M cells that sample Ag coming through the gut

Question 10

What are a few anatomical changes seen in germ-free mice?

Answer 10

enlarged cecum, longer small intestine, underdeveloped mesenteric lymph nodes

Question 11

What are a few immunological effects seen in germ-free mice?

Answer 11

reduced IgA secretion, reduced T cell numbers, reduced cytotoxicity of CD8 T cells

Question 12

A mucosal immune response (in comparison to a systemic response) is…

Answer 12

inflammatory

Question 13

In the mucosal surface what happens once bacteria gain access to the lamina propria via endocytosis?

Answer 13

Macrophages are activated, but inflammation is not triggered. Instead, local effector cells respond, and DCs travel to lymph nodes to activate adaptive immunity. From there, effector B and T cells particular for the bacteria colonize in the infected area and infection is terminated with little to no tissue damage.

Question 14

Intestinal epithelial cells serve as…

Answer 14

innate sensor cells

Question 15

TLR is found where and activates what?

Answer 15

Found on plasma membrane or in endosomes and activates NFkappaB

Question 16

TLR is found where and activates what?

Answer 16

found on plasma membrane or in endosomes and activates NFkappaB

Question 17

NOD is found where and activates what?

Answer 17

found in cytoplasm and activates NFkappaB

Question 18

What are the two functions of intestinal (non-inflammatory) macrophages once they’ve developed from blood monocytes?

Answer 18

phagocytosis and killing

Question 19

What is the name of the process of bacteria moving across the epithelium?

Answer 19

transcytosis

Question 20

What cells are in the Peyer’s patch that detect Ag?

Answer 20

DCs and B cells

Question 21

How can Dcs in the epithelium capture Ag?

Answer 21

Their processes can reach across the epithelial layer and capture Ag directly from the gut lumen

Question 22

How do DCs respond to food, micro biome, and pathogens?

Answer 22

They produce IL-10 to promote anti-inflammation, promote oral tolerance by driving differentiation of Treg cells to suppress antibodies being made against food that isn’t harmful

Question 23

Why is there no central tolerance to food Ag?

Answer 23

They were not present in the thymus

Question 24

What are some mechanisms of oral tolerance to food Ag?

Answer 24

anergy, deleting Ag-specific T cells, generation of Treg cells, producing IL-10 and TGF-beta

Question 25

Naive lymphocytes activated in a ______ _____ give rise to effector cells that ______ in the lymph and blood to gain access to the ______ ______ of the mucosal tissue.

Answer 25

peyer's patch; travel; lamina propria

Question 26

What does it mean to be an activated effector cell?

Answer 26

it means the cells acts immediately without causing inflammation

Question 27

Name a few immune cells in mucosal tissues that function as activated effector cells.

Answer 27

intraepithelial lymphocytes, CD8 T cells, CD4 T cells, plasma cells, mast cells, DC, macropahges

Question 28

What is the main function of intraepithelial lymphocytes?

Answer 28

function in repairing the mucosal epithelium

Question 29

_________ __ become attached to the mucous where they stand ready to bind _________ and __________ bacteria.

Answer 29

secretory Ab's; commensal; pathogenic

Question 30

What can be used to remove pathogens from the lamina propria?

Answer 30

secretory IgA

Question 31

Name one anatomical feature of the mucosal immune system.

Answer 31

peyer's patches, lymphoid follicles, tonsils, M cells

Question 32

Name two effector mechanisms of the mucosal immune system.

Answer 32

- activated effector T cells - plasma cells

Question 33

Name at least one immunoregulatory environment contributing to the mucosal immune system.

Answer 33

- downregulation of inflamatory immune responses to food - inflammation-anergic macorphages - tolerance-inducing DCs

Question 34

What year did the US stop vaccinations against smallpox?

Answer 34

1972

Question 35

What mediates immunological memory?

Answer 35

pathogen-specific B and T cells

Question 36

What maintains low levels os pathogen-specific Ab?

Answer 36

long-lived plasma cells

Question 37

When are long-lived clones of memory B and t cells produced?

Answer 37

during the primary immune response

Question 38

What happens in the secondary immune response?

Answer 38

memory B cells a re preferentially activated, Naive B cells become inhibited by IgG cross-linking the BCR and Fc-gamma-R

Question 39

Explain what causes eythroblastosis fetalis.

Answer 39

A baby who is Rh+ develops inside a mother who is Rh-. Because mom is Rh- negative she will build antibodies against Rh because the Ag is delivered on a B cell from the fetus. When she has a second pregnancy the anti-Rh Ab crosses the placenta and attacks the fetal RBCs.

Question 40

What is the original antigenic sin?

Answer 40

it's the tendency of people to make Ab against the epitopes expressed on the 1st flu virus variant they are exposed to...the Ab made against the original virus will suppress the response of naive B cells that are specific for the new epitope

Question 41

What is asymmetric division?

Answer 41

it is the division of a CD8 T cell undergoing mitosis upon activation by Ag and gives rise to one effector T cell and one memory T cell

Question 42

Explain the difference between naive and effector T cells.

Answer 42

naive: non-dividing, autophagy and mitophagy active, and dormat glycolysis effector: lots of division, components synthesized for mitosis

Question 43

What is the precursor of an effector cell vs a memory cell?

Answer 43

MTORC1=effector precursor