Oral and Intestinal Mucosal Immune System

Question 1

describe the epithelial layer of the oral mucosa

Answer 1

stratified squamous epithelium instead of a single layer

Question 2

describe the lamina propria of the oral mucosa

Answer 2

a thin layer of connective tissue rich in vascular networks, lymphatic vessels and immune cells and a key place for immune responses

Question 3

describe the mucosal-associated lymphoid tissue (MALT) of the small intestines and oral pharyngeal cavity

Answer 3

• peyers patches
• organized lymphoid follicles (tonsils and adenoids)

Question 4

what cells are present within the epithelial layer that contribute to innate immunity?

Answer 4

• microfold cells
• tuffs cells
• paneth cells

Question 5

what are microfold cells?

Answer 5

cells that transfer antigens to antigen presenting cells

Question 6

what are tuffs cells?

Answer 6

chemosensor cells

Question 7

what are paneth cells?

Answer 7

cells that secrete antimicrobials only in the small intestines

Question 8

how do NK cells and ILCs in the epithelium act as sentinels at the frontline of the innate immune response?

Answer 8

quickly producing IFN-gamma in response to pathogens

Question 9

what are the 3 functional subsets of ILCs and which T helper cells are they most similar to?

Answer 9

ILC1 most similar to Th1
ILC2 most similar to Th2
ILC3 most similar to Th17

Question 10

what are the two ILCs that are the major subsets in the oral cavity? in the intestines?

Answer 10

• ILC1 and ILC3 are major subsets in the oral mucosa
• ILC2 are in the intestines not the oral cavity

Question 11

what are peyers patches?

Answer 11

group of well-organized lymphoid follicles located in the lamina propria and submucosa of the distal portion of the small intestine—the ileum and jejunum and sometimes in the duodenum

Question 12

what is the T cell response in the small intestine?

Answer 12

Dendritic Cells (DCs) in the lamina propria extend dendrites into the gut epithelium to capture antigens and then migrate to Peyer’s patches, where they present the antigens to naive T cells, priming them for an immune response.

Question 13

where are T-alpha-beta lymphocytes primarily found?

Answer 13

parafollicular zone of Peyer’s patches

Question 14

what is the role of T helper 17 and T-gamma-delta?

Answer 14

Produce IL-17, a potent pro inflammatory cytokine important for defense against fungi (e.g., Candida) and controlling oral diseases like periodontitis and candidiasis

Question 15

where are B lymphocytes primarily located?

Answer 15

in the germinal centers of lymphoid follicles, such as those in Peyer’s patches and other mucosal tissues.

Question 16

what happens to the IgM-producing B cells within the lamina propria?

Answer 16

they differentiate into IgA-secreting plasma cells that produce immunoglobulin A (IgA), which is crucial for mucosal immunity.

Question 17

which pathways of the complement system can IgA activate?

Answer 17

only the alternative and lectin pathways

Question 18

in the intestinal tract, what must the immune system have?

Answer 18

tolerance to the normal intestinal flora, yet respond to pathogenic microorganisms

Question 19

what is the role of Treg cells in the intestinal tract?

Answer 19

play a critical role in maintaining immune tolerance and preventing excessive immune responses as well as maintain a delicate balance between active immunity and immunological tolerance

Question 20

what is the role of TGF-beta in the intestinal tract?

Answer 20

stimulates the production of IgA antibodies, which maintain the mucosal immunity.