Immunity

Question 1

Muscosa is vulnerable due to

Answer 1

Fragility and permeability

Requires effective defence mechanisms, portals of entry for non-pathogenic anitgens

Question 2

Intestinal lymphocytes are found

Answer 2

1. In organised tissues where immune responses are induced

2. Scattered throughout intestine where they carry out effector functions

Question 3

Peyer’s patches are found

Answer 3

in the small intestine

Question 4

Peyer’s patches are covered by an epithelial layer containing

Answer 4

Specialised M cells

Question 5

Characteristic of M cells

Answer 5

Ruffles

Question 6

How do M cells work

Answer 6

Take up antigen by endocytosis and transport to dendritic cell which activates T cells

Question 7

Adaptation of dendritic cells

Answer 7

Can reach through epithelial layer to capture antigen from lumen

Question 8

2 compartments of mucosal immune system

Answer 8

1. Immune cells of lamina propria

2. Immune cells of epithelial layer

Question 9

T cells enter Peyer’s patch from

Answer 9

blood vessels

Question 10

How do T cells in Peyer’s patch work

Answer 10

When activated, they drain through lymph nodes to thoracic duct and return to gut via bloodstream

Question 11

Paneth cells secrete

Answer 11

Defensins

Question 12

Where are Paneth cells found

Answer 12

SI not large

Question 13

IgA in GI tract

Answer 13

80%

Question 14

IgM in GI tract

Answer 14

15%

Question 15

IgG in GI tract

Answer 15

5%

Question 16

IgA

Answer 16

Can neutralise pathogens and toxins

Question 17

IgA internalised in endosomes

Answer 17

Export toxins and pathogens from lamina propria while being secreted

Question 18

Special T cells in gut

Answer 18

IEL’s

Intraepithelial lymphocytes

Question 19

IEL’s

Answer 19

80% CD8+

1. Virus infects mucosal epithelium cell
2. Activated IEL kills epithelial cell by Fas dependant pathway

Question 20

Infectious disease

Answer 20

Infection crosses mucosa and fuses to dendritic cells which shuttle virus to lymph nodes
Infection spreads to CD4+ lymphocytes
Viral infected cells go into bloodstream and disseminate across body

Question 21

Primary Immunodeficiency

Answer 21

Selective IgA deficiency
CVID
XLA
CGD
SCID

Question 22

Selective IgA deficiency

Answer 22

Aysmptomatic

Recurrent sino-pulmonary infection (coeliac disease X10)

Question 23

Common Variable Immunodeficiency

Answer 23

Recurrent sino-puomonary and GI infections (low IgM+G)

Question 24

X linked Agammaglobulinaemia

Answer 24

Sino-pulmonary and GI infetcions

Devastating entervoviral infection (no B cells)

Question 25

Chronic Granulomatous disease

Answer 25

Staph aureus/inflammatory granulomas

Abscesses

Question 26

Severe combines immunodeficiency

Answer 26

Defect in T and B cell immunity

Oral candidas, rotavirus, EBV

Question 27

Allergy

Answer 27

IgE secreted by plasma cells binds to mast cells
Secrete signals to B cells
Stimulates further IgE production

Question 28

Common allergens

Answer 28

Drugs, serum, venom and food (peanuts)

Question 29

Crohn’s

Answer 29

Mediated by Th1 CD4+ T cells
Gamma inteferon
IL-12
TNF alpha
Gene = NOD2

Question 30

UC

Answer 30

May be NK T cell mediated via IL-13