immunological functions of the alimentary tract

Question 1

features of innate IS

Answer 1

prevents infection
avoids disease
isn’t specific
doesn’t have memory

Question 2

what mediated innate IS

Answer 2

macrophages
epithelial barriers
secretions

Question 3

features of the adaptive IS

Answer 3

responds to infection
prevents disease
responds with specificity to targeted microbe
has memory

Question 4

what mediated the adaptive IS

Answer 4

lymphocytes, antibodies

Question 5

systemic sources of immunity

Answer 5

bone marrow
spleen thymus
lymph system
blood circulation

Question 6

mucosal sources of immunity

Answer 6

mucous membranes - eyes, nose, mouth, lungs, gut, genitourinary tract

Question 7

innate protective mechanisms in the mucosal immune system

Answer 7

mucin
peristalsis
antimicrobial peptides and proteins
e.g lysozyme, lactoferrin, phagocytes

Question 8

innate aspects of the mucosal barrier

Answer 8

mucin
peristalsis
proteolysis
microvillus membrane, or squamous cell

Question 9

immunological aspects of mucosal barrier

Answer 9

secretory IgA/IgM, IgG

Question 10

3 lymphoid cells in the gut

Answer 10

intra-epithelial lymphocytes
lymphocytes and macrophages scattered in the lamina propria
peyer’s patches

Question 11

what does GALT stand for

Answer 11

gut assoc lymphoid tissues

Question 12

what are m cells

Answer 12

membranous/microfold cells

Question 13

where are m cells found

Answer 13

GALT of Peyer’s patches in the GIT

Question 14

what do m cells do

Answer 14

initiate immune responses on their apical membrane - allow microbe transport from gut lumen to lamina propria

Question 15

targets for uptake by m cells

Answer 15

particles/macromolecules - eg cholera toxin
viruses eg polio, HIV
parasites eg cryptosporidium
bacteria eg cholera, salmonella

Question 16

what role do mucosal lymphocytes play in immune homeostasis

Answer 16

• mucosal defence from pathogens
• ignore harmless bacteria
• support the growth and repair of epithelial cells
• pathogenesis of inflammatory intestinal diseases

Question 17

what is the predominant mucosal antibody

Answer 17

Serum IgA -SIgA

Question 18

where are mucosal antibodies found

Answer 18

all secretions

breast milk - provides passive immune protection in newborns

Question 19

mechanism of action of IgG

Answer 19

binds to key functional sites on microbes/toxins
agglutination
induces inflammation
recruits immune cells

Question 20

mechanism of action of SIgA

Answer 20

• binds to key functional sites on microbes/toxins
• agglutes (more effectively than IgG)
• causes intracellular neutralisation and immune exclusion
• aids virus secretion
• interacts with non specific factors e.g. lysozymes, lactoferrin, peroxidases

Question 21

what is oral tolerance

Answer 21

general immunosuppressive state in the oral mucosa that prevents reaction to harmless Ags like commensals or foods
- it generates systemic immune unresponsiveness