lecture 8 exam 2

Question 1

SubQ or intramuscular immunization routes

Answer 1

antigen drains to nearest LN and stimulates SYSTEMIC immunity NOT mucosal immunity

Question 2

peripheral immune system & draining lymph nodes

Answer 2

facial
retropharyngeal
submandibular
superficial cervical
axillary
iliac
superficial inguinal
femoral
popliteal

Question 3

innate protection mechanisms on body surfaces

Answer 3

vomiting/saliva
turbulence/sneezing
tears/blinking
mucus/cilia/coughin
dessication/desqamation/fatty acids/normal flora
acid pH/vomiting
normal flora/anaerobiasis/lysozyme/defensins/proteases/diarrhea

Question 4

mucosa-associated lymphoid tissues (MALT)

Answer 4

MALT cellular mass: excess total lymphoid cells in bone marrow, thymus, spleen and LN

ex: NALT, GALT, BALT

Question 5

NALT

Answer 5

type of MALT

nasal associated lymphoid tissue - tonsils

Question 6

GALT

Answer 6

type of MALT

gut associated lymphoid tissue - peyers patches

Question 7

BALT

Answer 7

type of MALT

bronchus associated lympoid tissue

Question 8

epithelial barrier

Answer 8

mucosal epithelium in lumen
peyeres patches dense with lymphocytes in ileum
lamina propria has lymphocytes, lymphatic systems

Question 9

intestinal lumen

Answer 9

commensal bacteria

IgA from antibody (blood borne)

Question 10

mucosal epithelium

Answer 10

mucus
goblet cell
M cell
intestinal epithelial cell
dendritic cell
crypt
intraepithelial lymphocytes
vilus
paneth cells
defensins

Question 11

lamina propria

Answer 11

plasma cell - IgA
peyers patch
follicle
macrophage
mast cell
T cell
B cell
LYMPH DRAINAGE VIA AFFERENT LYMPHATIC
dendritic cell

Question 12

mesentary

Answer 12

mesenteric LN

• homing of lymphocytes to intestinal mucosa
• priming of antigen specific responses taking place here

Question 13

properties of MALT

Answer 13

large lymphoid areas
-continuously exposed to microorganisms and food antigens
-mucous membranes largest organ
partially separate from the peripheral immune system
epithelial barrier (innate immunity)
produces T cell and B cell effectors and memory cells:
-generated in one location then circulate to distant sites
provides tolerance to food antigens

Question 14

epithelial barrier immune functions

Answer 14

epithelial tight junctions

mucus: mucins, lipids & bicarbonate fluid
- secreted by goblet cells
- neutral pH at epithelial layer
- adhere to luminal surface of epithelium: allow nutrients but not macromolecules to pass
defensins: antimicrobial peptides secreted by paneth cells
- disrupt bacterial membranes

Question 15

epithelial cells produce cytokines and chemokines

Answer 15

IL10/TGFB - immunosuppressive (inflammation)
TNFalpha - Th1 differnetiation
CXCL1 - neutrophils
CCL2 - eosinophils
CXCL10 - lymphocytes recruitment

Question 16

compartments of MALT

Answer 16

inductive sites

effector sites distant from inductive sites

Question 17

inductive sites of MALT

Answer 17

antigen is process and T and B cells are activated
antibody class switching occurs

Question 18

effector sites of MALT

Answer 18

sites where antibody and cell mediated responses are generated against pathogens:
antibody is released by plasma cells
CTLs kill virus infected cells

Question 19

inductive site examples

Answer 19

tonsils - most mammals except rodents
pharynx, NALT
BALT
appendix
peyers patches (discrete in jejunum)
mesenteric LN

Question 20

anigen transport across mucosal epithelium

Answer 20

M cells - take bacteria into epithelium and give to DC, located w/in epithelial cells
intestinal mucosa DCs - read or let in antigen to find DC, CDs CXs TGFb to t cell or treg

Question 21

discrete peyers patches in jejunum

Answer 21

dome region: CD4 T cells, DCs, macrophages
germinal center: B cells (class switching)
parafollicular region: CD4, CD8, DCs and macrophages

antigen transfer by M cells into lymphoid follicle

Question 22

model for T cell differentiation in inductive sites

Answer 22

M cell brings antigens in and presents to DC resulting in a. IL10/TGFB expression response to low dose antigen (food)

b. IL4 expression response to extracellular pathogen parasites
c. IL12 expression response to intracellular pathogen
d. IL23 expression response to endogenous flora

Question 23

IL10/TGFbeta response to low does antigen “food” results in

Answer 23

Treg w default IL10 and TGFbeta

Question 24

IL4 response to extracellular pathogen parasites results in

Answer 24

Th2 w default IL4, 5, 10

Question 25

IL12 response to intracellular pathogen results in

Answer 25

Th1 w default IFNgamma

Question 26

IL23 response to endogenous flora results in

Answer 26

Th17 w default IL17, 6

Question 27

intestinal villi components

Answer 27

``` intraepithelial lymphocytes (IEL) - gamma delta T cells, CD8+ alpha beta T cells lamina propria + lymphocytes - CD4 tcells activating B cells crypt epithelium paneth cells - lysozyme and defensins ```

Question 28

homing properties of intestinal lymphocytes

Answer 28

Mcell call in antigen and HEV brings in DC/naive T cell, and B cell to interact and go through mesenteric LN to lymph to heart to blood to chemokines direct homing of effector lymphocytes (CD4, CTLs, and B cells)

Question 29

secretory IgA is the

Answer 29

main mucosal immunoglobulin in most animal species except: cattle - igG is most important mucosal

Question 30

T dependent IgA class switching in gut - antigen

Answer 30

done by plasma cell through interactions of antigen w DC and B cell DC to naive CD4+ tcell then activated Thelp w B cell receiving NO and TGFb from DC to become plasma cell and leave the peyers patch into lamina propria

Question 31

T independent IgA class switching in gut - bacteria/PAMP

Answer 31

DC TLR interacts w bacteria and APRIL, TGFB, BAFF released to IgM+ b cell to travel as plasma cell to lamina propria and release IgA

Question 32

APRIL

Answer 32

A proliferation inducing ligand | released by DC in response to bacteria/PAMP

Question 33

BAFF

Answer 33

bcell activating factor of the TNF family | released by DC in response to bacteria/PAMP

Question 34

transport of IgA across epithelial cells

Answer 34

Jchain is released and hold dimeric IgA in lamina propria attaches to polyIg receptor - bound IgA and enter mucosal epithelial cell endocytosed complex of IgA and polyIg receptor and proteolytic cleavage occurs on apical side to secrete IgA

Question 35

immune elimination of intestinal round worms

Answer 35

``` when worm gets to tissue eosinophils (IL5, IL13 signal) attack and B cell reads antigens and bind to Th2 in submucosa, releasing IL4 IL4 activates class switching from IgM to IgE in plasma cell IgE on mast cell releases histamine which leads to vascular permeability leading to smooth muscle contraction which brings more fluid into the lumen IgG + C =MAC and attacks on luminal side causing expulsion ```

Question 36

ADCC of parasites by eosinophils

Answer 36

helminths are vulnerable to : ADCCA involving eosinophils, neutrophils and macrophages ``` eosinophil degranulation releases: major basic protein (MBP) eosinophil cationic protein (ECP) eosinophil peroxidase (EP) eosinophil neurotoxin (EN) phospholipase D lysophospholipase all these are toxic to helminths ``` IgE is antibody for eosinophils and helminths

Question 37

treg functions at mucosal surfaces

Answer 37

inhibit th2, th1, th17 to regulate immune system