EXAM 3 Mucosal Immunity

Question 1

mucosal surfaces are ___ and prominent at sites of ___

Answer 1

• widespread
• infection

Question 2

what are the 3 compartments of mucosal tissues?

Answer 2

1. epithelium
2. lamina propria
3. mucosal-associated lymphoid tissue (MALT)

Question 3

describe the epithelium of mucosal tissue

Answer 3

• single (gut) or multi-celled (mouth) barrier
• intraepithelial lymphocytes (IEL)
  
  • gamma delta T cells
  • CD8 alpha alpha T cells
  • memory CD8 T cells

Question 4

describe the lamina propria of mucosal tissues

Answer 4

• lymphatic tissue
• gamma delta T cells
• CD8 T cells
• CD4 T cells - Th1, Th17
• plasma cells and memory B cells
• macrophages
• dendritic cells

Question 5

describe the mucosal-associated lymphoid tissue of mucosal tissue

Answer 5

• specialized per mucosal tissue
• lymph node-like organization

Question 6

what is waldeyer’s ring?

Answer 6

a ring of lymphoid tissues in the oral cavity formed by the tonsils and adenoids

around the entrance of the gut and airway

Question 7

what are the specialized mucosal tissues of the mouth?

Answer 7

tonsils and adenoids

Question 8

do mucosal infections follow the traditional inflammatory cascade?

Answer 8

no

Question 9

describe how mucosal immunity often employs limited inflammation

Answer 9

• strong proactive immunity, limited reactive immunity
• most infections often cleared without an inflammatory response
• local innate and adaptive cells respond
• inflammation occurs (neutrophils recruited) if the infection is severe, persists, and/or causes tissue damage

Question 10

what are the anatomical features of the mucosal immune system?

Answer 10

• intimate interactions between mucosal epithelia and lymphoid tissues
• discrete compartments of diffuse lymphoid tissue and more organized structures such as peyer’s patches, isolated lymphoid follicles, and tonsils
• specialized antigen-uptake mechanisms; ex. m cells in peyers patches, adenoids, and tonsils

Question 11

what are the effector mechanisms of the mucosal immune system?

Answer 11

• activated/memory T cells predominate even in the absence of infection
• multiple activated natural effectore/regulatory T cells present
• secretory IgA antibodies
• presence of distinctive microbiota

Question 12

describe the immunoregulatory environment of the mucosal immune system

Answer 12

• active downregulation of immune responses (ex. to food and other innocuous antigens) predominate
• inhibitory macrophages and tolerance-inducing dendritic cells

Question 13

describe the 2 ways that local adaptive immune cells resolve infection

Answer 13

Question 14

referring to bacteria:

in the gingival sulcus, there is ___ diversity and richness; in a subgingival periodontal pocket, there is ___ diversity and richness

Answer 14

low, high

Question 15

describe how the microbiome is constantly shaped at mucosal surfaces

Answer 15

• mucosal layer extablishment
• secreted immune components
  
  • antimicrobial peptides
  • IgA
• immune browsing
• the microbiome shapes the mucosal immune system

Question 16

how does the microbiome influence CD4 T cell differentiation?

Answer 16

• TGF-beta prominent at mucosal surfaces
• mucosal microbiome affects local cytokine environment, and CD4 T cell differentiation
  
  • TGF-beta + no inflammatory cytokines: Treg cells
  • TGF-beta + inflammatory cytokines: Th17 cells
• Treg cells inhibit mucosal inflammation
• Th17 cells
  
  • neutrophil recruitment
  • antimicrobial peptide production
  • tissue repair

Question 17

in oral immunity, ___ cells protect barriers and induce inflammation when needed

Answer 17

Th17

Question 18

Th17 cells release IL-17 and IL-22. what does this do?

Answer 18

1. regulate tight junction protein expression
   
   1. maintain barrier integrity
2. induce antimicrobial peptide production
   
   1. beta defensins
   2. cathelicidins
   3. lactoferrin
3. induce neutrophil chemokine expression

Question 19

impaired or excessive Th17 function is linked to ___

Answer 19

oral disease

Question 20

what two oral diseases can result from impaired or excessive Th17 function?

Answer 20

chronic mucocutaneous candidiasis and periodontitis

Question 21

describe chronic mucocutaneous candidiasis

Answer 21

• persistent fungal infection of the skin, nails, and mucous membranes (overgrowth of fungus)
• deficient IL-17 signaling
• numerous causes:
  
  • deficient IL-17, impaired Th17 differentiation, or impaired Th17 development
• oral manifestation

Question 22

describe periodontitis

Answer 22

• overgrowth of bacterial communities
• increased IL-17 expression corresponds to increased disease severity
• chronic and excessive neutrophil recruitment
• chronic inflammatory cytokine production
• osteoclast activation

Question 23

what are the important roles that immunoglobulin secretion plays?

Answer 23

• pathogen neutralization
• toxin removal
• antigen browsing
• shapes microbiome
• predominantly IgA

Question 24

describe how mucosal antigens are constantly browsed

Answer 24

• simultaneous mechanisms
• DC and macrophage antigen exposure
• impacts IgA and antimicrobial peptide production and release
• commensal bacteria repress an immune response
• pathogenic bacteria trigger an immune response

Question 25

how are epithelial cells active immune components?

Answer 25

• actively direct immune responses
• expresses TLR and NOD receptors
• form inflammasomes
• phagocytose mucosal bacteria
• express cytokines and antimicrobial peptides
• induces local immune responses

Question 26

how do established pathogens illicit inflammatory responses?

Answer 26

• pathogen evades mucosal immunity
• local macrophages and DCs are activated
  
  • neutrophil recruitment
  • Th17, Th1 response

Question 27

what are the 6 ways mucosal antigens are constantly browsed?

Answer 27