Mucosal Immunology 1

Question 1

MALT, BALT, GALT

• The mucosa-associated lymphatic tissue (MALT) is divided into
  
  • BALT (…-associated lymphatic tissue)
  • and
  • GALT (… -associated lymphatic tissue)

Answer 1

• The mucosa-associated lymphatic tissue (MALT) is divided into
  
  • BALT (bronchus-associated lymphatic tissue)
  • and
  • GALT (gut -associated lymphatic tissue)

Question 2

MALT, BALT, GALT

• The …-associated lymphatic tissue (MALT) is divided into
  
  • BALT (bronchus-associated lymphatic tissue)
  • and
  • GALT (gut -associated lymphatic tissue)

Answer 2

• The mucosa-associated lymphatic tissue (MALT) is divided into
  
  • BALT (bronchus-associated lymphatic tissue)
  • and
  • GALT (gut -associated lymphatic tissue)

Question 3

Why is the mucosal immune system so very important?

• It is the … immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours …% of all effector cells
• It is in direct contact with the outside environment
• There is continuous antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Answer 3

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in direct contact with the outside environment
• There is continuous antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Question 4

Why is the mucosal immune system so very important?

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in direct contact with the … environment
• There is … antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Answer 4

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in direct contact with the outside environment
• There is continuous antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Question 5

Why is the mucosal immune system so very important?

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in … contact with the outside environment
• There is continuous … stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Answer 5

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in direct contact with the outside environment
• There is continuous antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Question 6

Why is the mucosal immune system so very important?

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in direct contact with the outside environment
• There is continuous antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many … and an important target site for …-induced protection

Answer 6

• It is the biggest immune compartment of the organism
• With an estimated surface area of 400 m2 it harbours 60% of all effector cells
• It is in direct contact with the outside environment
• There is continuous antigen stimulation (food, endogenous flora, & pathogens)
• Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Question 7

… sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Answer 7

Mucosal sites are the ports of entry for many infections and an important target site for vaccine-induced protection

Question 8

Mucosal surfaces are a prime site of entry for … pathogens

Answer 8

Mucosal surfaces are a prime site of entry for infectious pathogens

Question 9

… surfaces are a prime site of entry for infectious pathogens

Answer 9

Mucosal surfaces are a prime site of entry for infectious pathogens

Question 10

• Most of the pathogens that cause the deaths of large numbers of people are those of mucosal surfaces or enter the body through these routes. The genitourinary, rectal and oral mucosa are the main mucosal transmission routes for … infection, for example.
• If a vaccine could induce both … and local mucosal immunity it would offer the best possible protection against mucosal … transmission and ….

Answer 10

• Most of the pathogens that cause the deaths of large numbers of people are those of mucosal surfaces or enter the body through these routes. The genitourinary, rectal and oral mucosa are the main mucosal transmission routes for HIV infection, for example.
• If a vaccine could induce both systemic and local mucosal immunity it would offer the best possible protection against mucosal HIV transmission and AIDS.

Question 11

1. The main defence strategies of intestinal mucosa & oropharynx (1)

• Endogenous …
  
  • 1014 bacteria, hundreds of different species (10x more than all cells in the human body)
• Epithelium and …
  • Mechanical … (cells, tight junctions)
  • Mucins (extensively glycosylated proteins) form a viscous barrier
  • … epithelial cells (goblet cells, absorptive epithelial cells, M cells, Paneth cells)
  • … substances (defensins, lysozyme, lactoferrin, phospholipases )

Answer 11

• Endogenous flora
  
  • 1014 bacteria, hundreds of different species (10x more than all cells in the human body)
• Epithelium and Mucus
  • Mechanical Barriers (cells, tight junctions)
  • Mucins (extensively glycosylated proteins) form a viscous barrier
  • Specialised epithelial cells (goblet cells, absorptive epithelial cells, M cells, Paneth cells)
  • Antimicrobial substances (defensins, lysozyme, lactoferrin, phospholipases )

Question 12

1. The main defence strategies of intestinal mucosa & oropharynx (1)

• … flora
  
  • 1014 bacteria, hundreds of different species (10x more than all cells in the human body)
• Epithelium and Mucus
  • … Barriers (cells, tight junctions)
  • Mucins (extensively … proteins) form a viscous barrier
  • Specialised epithelial cells (goblet cells, absorptive epithelial cells, M cells, Paneth cells)
  • … substances (defensins, lysozyme, lactoferrin, phospholipases )

Answer 12

• Endogenous flora
  
  • 1014 bacteria, hundreds of different species (10x more than all cells in the human body)
• Epithelium and Mucus
  • Mechanical Barriers (cells, tight junctions)
  • Mucins (extensively glycosylated proteins) form a viscous barrier
  • Specialised epithelial cells (goblet cells, absorptive epithelial cells, M cells, Paneth cells)
  • Antimicrobial substances (defensins, lysozyme, lactoferrin, phospholipases )

Question 13

1. The main defence strategies of intestinal mucosa & oropharynx (2)

• (3) Regionalised Immune System
  
  • Waldeyer’s ring (lingual and palatine tonsils, nasopharyngeal tonsils)
  • …´s patches
• In Part II:
  
  • … lymph nodes
  • Intraepithelial immune cells
  • Lamina … immune cells
• (4) Gut homing of B and T cells
  
  • Immune cells primed in the induction sites return to the relevant effector sites (homing)

Answer 13

• (3) Regionalised Immune System
  
  • Waldeyer’s ring (lingual and palatine tonsils, nasopharyngeal tonsils)
  • Peyer´s patches
• In Part II:
  
  • Mesenteric lymph nodes
  • Intraepithelial immune cells
  • Lamina propria immune cells
• (4) Gut homing of B and T cells
  
  • Immune cells primed in the induction sites return to the relevant effector sites (homing)

Question 14

1. The main defence strategies of intestinal mucosa & oropharynx (2)

• (3) Regionalised Immune System
  
  • Waldeyer’s ring (lingual and palatine tonsils, nasopharyngeal tonsils)
  • …´s patches
• In Part II:
  
  • Mesenteric lymph nodes
  • Intraepithelial immune cells
  • Lamina propria immune cells
• (4) Gut … of B and T cells
  
  • Immune cells primed in the induction sites return to the relevant effector sites (homing)

Answer 14

• (3) Regionalised Immune System
  
  • Waldeyer’s ring (lingual and palatine tonsils, nasopharyngeal tonsils)
  • Peyer´s patches
• In Part II:
  
  • Mesenteric lymph nodes
  • Intraepithelial immune cells
  • Lamina propria immune cells
• (4) Gut homing of B and T cells
  
  • Immune cells primed in the induction sites return to the relevant effector sites (homing)

Question 15

… is a major factor in maintaining a healthy composition of the micro-organisms living in the gut. Microbiota and microbiome are often used interchangeably, however, ‘microbiota’ technically speaking refers to the actual microorganisms whereas the ‘microbiome’ refers to the totality of their genes

Answer 15

Diet is a major factor in maintaining a healthy composition of the micro-organisms living in the gut. Microbiota and microbiome are often used interchangeably, however, ‘microbiota’ technically speaking refers to the actual microorganisms whereas the ‘microbiome’ refers to the totality of their genes

Question 16

… is a major factor in maintaining a healthy composition of the micro-organisms living in the gut.

Answer 16

Diet is a major factor in maintaining a healthy composition of the micro-organisms living in the gut.

Question 17

1. The main defence strategies of intestinal mucosa & oropharynx (8)

• (1) … diet
  
  • Rich in fibre, supports healthy gut microbiota
  • … produced by bacteria
  • Increased mucus production, increased antimicrobial peptide production
  • Increased expression of tight junction proteins
• (2) Typical ‘…’ diet
  
  • Low in fibre
  • Diversity of bacteria …
  • … SCFA production
  • More (chronic) inflammation
  • leakiness

Answer 17

• (1) Prudent diet
  
  • Rich in fibre, supports healthy gut microbiota
  • SCFAs produced by bacteria
  • Increased mucus production, increased antimicrobial peptide production
  • Increased expression of tight junction proteins
• (2) Typical ‘Western’ diet
  
  • Low in fibre
  • Diversity of bacteria reduced
  • Low SCFA production
  • More (chronic) inflammation
  • leakiness

Question 18

1. The main defence strategies of intestinal mucosa & oropharynx (8)

• (1) Prudent diet
  
  • Rich in …, supports healthy gut microbiota
  • SCFAs produced by bacteria
  • … mucus production, … antimicrobial peptide production
  • … expression of tight junction proteins
• (2) Typical ‘Western’ diet
  
  • Low in …
  • Diversity of bacteria reduced
  • Low SCFA production
  • More (chronic) inflammation
  • l…

Answer 18

• (1) Prudent diet
  
  • Rich in fibre, supports healthy gut microbiota
  • SCFAs produced by bacteria
  • Increased mucus production, increased antimicrobial peptide production
  • Increased expression of tight junction proteins
• (2) Typical ‘Western’ diet
  
  • Low in fibre
  • Diversity of bacteria reduced
  • Low SCFA production
  • More (chronic) inflammation
  • leakiness

Question 19

Prudent diet

• Rich in …, supports healthy gut …
• SCFAs (short chain FA) produced by bacteria
• Increased … production, increased antimicrobial peptide production
• Increased expression of tight … proteins

Answer 19

• Rich in fibre, supports healthy gut microbiota
• SCFAs (short chain FA) produced by bacteria
• Increased mucus production, increased antimicrobial peptide production
• Increased expression of tight junction proteins

Question 20

Typical ‘Western’ diet

• Low in …
• … of bacteria reduced
• … SCFA production
• More (…) inflammation
• leakiness

Answer 20

• Low in fibre
• Diversity of bacteria reduced
• Low SCFA production
• More (chronic) inflammation
• leakiness

Question 21

Intestinal Epithelial Cells (1)

• Epithelial cells:
  
  • …
  • TLRs (TLR2,4,5,6,7,9 depending on region of gut).
  • TLR5 on … surface activated by bacteria.
  • NLR in cytoplasm activated by … (invading bacteria)

Answer 21

• Epithelial cells:
  
  • Microvilli
  • TLRs (TLR2,4,5,6,7,9 depending on region of gut).
  • TLR5 on basolateral surface activated by bacteria.
  • NLR in cytoplasm activated by flagellins (invading bacteria)

Question 22

… at basolateral surface tightens tight junctions upon contact with bacteria

Answer 22

TLR5 at basolateral surface tightens tight junctions upon contact with bacteria

Question 23

TLR5 at … surface tightens tight junctions upon contact with bacteria

Answer 23

TLR5 at basolateral surface tightens tight junctions upon contact with bacteria

Question 24

Intestinal Epithelial Cells (2) (Paneth, Goblet and M Cells)

• Paneth cells
  
  • produce human … 5 (HD5) precursor & HD6 precursor,
  • … (activates HD5 and HD6 by proteolytic cleavage
• Goblet cells
  
  • Produce … as a physicochemical barrier
  • Antibacterial peptides and antibodies of IgG secretory IgA type are dispersed in the mucus
  • (-> transepithelial transport of IgA)
• M cells
  
  • transport … from gut lumen to subepithelial lymphoid structures (-> Peyer’s patches)

Answer 24

• Paneth cells
  
  • produce human defensin 5 (HD5) precursor & HD6 precursor,
  • Trypsin (activates HD5 and HD6 by proteolytic cleavage
• Goblet cells
  
  • Produce mucus as a physicochemical barrier
  • Antibacterial peptides and antibodies of IgG secretory IgA type are dispersed in the mucus
  • (-> transepithelial transport of IgA)
• M cells
  
  • transport antigens from gut lumen to subepithelial lymphoid structures (-> Peyer’s patches)

Question 25

Intestinal Epithelial Cells (2) (Paneth, Goblet and M Cells)

• Paneth cells
  
  • produce human … 5 (HD5) precursor & HD6 precursor,
  • Trypsin (activates HD5 and HD6 by proteolytic cleavage
• Goblet cells
  
  • Produce mucus as a … barrier
  • … peptides and antibodies of IgG secretory IgA type are dispersed in the mucus
  • (-> transepithelial transport of IgA)
• M cells
  
  • transport antigens from gut lumen to subepithelial … structures (-> Peyer’s patches)

Answer 25

• Paneth cells
  
  • produce human defensin 5 (HD5) precursor & HD6 precursor,
  • Trypsin (activates HD5 and HD6 by proteolytic cleavage
• Goblet cells
  
  • Produce mucus as a physicochemical barrier
  • Antibacterial peptides and antibodies of IgG secretory IgA type are dispersed in the mucus
  • (-> transepithelial transport of IgA)
• M cells
  
  • transport antigens from gut lumen to subepithelial lymphoid structures (-> Peyer’s patches)

Question 26

Intestinal Epithelial Cells (2) (Paneth cells)

• Paneth cells
  
  • produce … … 5 (HD5) precursor & HD6 precursor,
  • … (activates HD5 and HD6 by proteolytic cleavage)

Answer 26

• produce human defensin 5 (HD5) precursor & HD6 precursor,
• Trypsin (activates HD5 and HD6 by proteolytic cleavage)

Question 27

Intestinal Epithelial Cells (2) (Goblet Cells)

• Goblet cells
  
  • Produce … as a … barrier
  • Antibacterial peptides and antibodies of IgG secretory IgA type are dispersed in the mucus
  • (-> transepithelial transport of IgA)

Answer 27

• Goblet cells
  
  • Produce mucus as a physicochemical barrier
  • Antibacterial peptides and antibodies of IgG secretory IgA type are dispersed in the mucus
  • (-> transepithelial transport of IgA)

Question 28

Intestinal Epithelial Cells (4) (M Cells)

• transport … from gut lumen to subepithelial lymphoid structures (-> …. patches)

Answer 28

• transport antigens from gut lumen to subepithelial lymphoid structures (-> Peyer’s patches)

Question 29

Label the intestinal epithelial cells

Answer 29

Question 30

Label the intestinal epithelial cells

Answer 30

Question 31

Peyer´s Patches (PPs) and associated immune cells (1)

• … complexes along the gastrointestinal tract. The volume of the rings indicates the relative amount of … tissue.
• The largest amount of … tissue is found in the … (Waldeyer’s ring) and terminal ileum.

Answer 31

• Lymphoid complexes along the gastrointestinal tract. The volume of the rings indicates the relative amount of lymphoid tissue.
• The largest amount of lymphoid tissue is found in the oropharynx (Waldeyer’s ring) and terminal ileum.

Question 32

Peyer´s Patches (PPs) and associated immune cells (1)

• Lymphoid complexes along the gastrointestinal tract. The … of the rings indicates the relative amount of lymphoid tissue.
• The largest amount of lymphoid tissue is found in the oropharynx (Waldeyer’s ring) and terminal …

Answer 32

• Lymphoid complexes along the gastrointestinal tract. The volume of the rings indicates the relative amount of lymphoid tissue.
• The largest amount of lymphoid tissue is found in the oropharynx (Waldeyer’s ring) and terminal ileum.

Question 33

Peyer´s Patches (PPs) and associated immune cells (2)

• PPs are located in the distal … in areas of follicle associated epithelium (FAE)
• The foetal small intestine contains on average 60 PPs before week 30 of gestation and their number steadily …
• PPs contain … centres for B- and T cells

Answer 33

• PPs are located in the distal ileum in areas of follicle associated epithelium (FAE)
• The foetal small intestine contains on average 60 PPs before week 30 of gestation and their number steadily increases reaching a maximum of about 240 at puberty
• PPs contain germinal centres for B- and T cells

Question 34

Peyer´s Patches (PPs) and associated immune cells (2)

• PPs are located in the distal ileum in areas of … associated … (FAE)
• The foetal small intestine contains on average 60 PPs before week 30 of gestation and their number steadily increases reaching a maximum of about 240 at …
• PPs contain … centres for B- and T cells

Answer 34

• PPs are located in the distal ileum in areas of follicle associated epithelium (FAE)
• The foetal small intestine contains on average 60 PPs before week 30 of gestation and their number steadily increases reaching a maximum of about 240 at puberty
• PPs contain germinal centres for B- and T cells

Question 35

Peyer´s Patches (PPs) and associated immune cells (3)

• What area has the majority of payer’s patches?

Answer 35

Question 36

Peyer´s Patches (PPs) and associated immune cells (4)

• Follicle associated epithelium contains M-cells (approx. 100-150/PP).
• M-cells feature:
  
  • …. microvilli (microfolds)
  • … cell membrane fenestrations
    
    • enhancing antigen uptake from the gut lumen (fluid-phase endocytosis)
  • A trans-cellular transport mechanism for antigen
  • … at the basolateral membrane
    
    • delivers antigen to dendritic cells (DCs) of underlying lymphatic structures

Answer 36

• Follicle associated epithelium contains M-cells (approx. 100-150/PP).
• M-cells feature:
  
  • Small microvilli (microfolds)
  • Large cell membrane fenestrations
    
    • enhancing antigen uptake from the gut lumen (fluid-phase endocytosis)
  • A trans-cellular transport mechanism for antigen
  • Exocytosis at the basolateral membrane
    
    • delivers antigen to dendritic cells (DCs) of underlying lymphatic structures

Question 37

Peyer´s Patches (PPs) and associated immune cells (4)

• Follicle associated epithelium contains M-cells (approx. 100-150/PP).
• M-cells feature:
  
  • Small microvilli (microfolds)
  • Large cell membrane …
    
    • enhancing antigen … from the gut lumen (fluid-phase endocytosis)
  • A trans-cellular transport mechanism for antigen
  • Exocytosis at the basolateral membrane
    
    • delivers antigen to … cells (DCs) of underlying lymphatic structures

Answer 37

• Follicle associated epithelium contains M-cells (approx. 100-150/PP).
• M-cells feature:
  
  • Small microvilli (microfolds)
  • Large cell membrane fenestrations
    
    • enhancing antigen uptake from the gut lumen (fluid-phase endocytosis)
  • A trans-cellular transport mechanism for antigen
  • Exocytosis at the basolateral membrane
    
    • delivers antigen to dendritic cells (DCs) of underlying lymphatic structures

Question 38

Peyer´s Patches (PPs)

• Fill in the blanks

Answer 38

Question 39

Peyer´s Patches (PPs)

• Fill in the blanks

Answer 39

Question 40

Peyer´s Patches (PPs) and associated immune cells (6)

• … areas:
  
  • Lymphoid follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • Follicular dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• … areas and Subepithelial dome (SED)
  
  • containing mixed-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Answer 40

• Follicular areas:
  
  • Lymphoid follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • Follicular dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• Interfollicular areas and Subepithelial dome (SED)
  
  • containing mixed-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Question 41

Peyer´s Patches (PPs) and associated immune cells (6)

• Follicular areas:
  
  • Lymphoid follicles with a … center (GC) containing … B-lymphocytes
  • Follicular … cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• Interfollicular areas and Subepithelial dome (SED)
  
  • containing …-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Answer 41

• Follicular areas:
  
  • Lymphoid follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • Follicular dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• Interfollicular areas and Subepithelial dome (SED)
  
  • containing mixed-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Question 42

Peyer´s Patches (PPs) and associated immune cells (6)

• Follicular areas:
  
  • … follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • … dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • … (proper APCs, class-II MHC)
• Interfollicular areas and … dome (SED)
  
  • containing mixed-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Answer 42

• Follicular areas:
  
  • Lymphoid follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • Follicular dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• Interfollicular areas and Subepithelial dome (SED)
  
  • containing mixed-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Question 43

Peyer´s Patches (PPs) and associated immune cells (6)

• Follicular areas:
  
  • Lymphoid follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • Follicular dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• Interfollicular areas and Subepithelial dome (SED)
  
  • containing mixed-cells, including what 4 types of cell?

Answer 43

• Follicular areas:
  
  • Lymphoid follicles with a germinal center (GC) containing proliferating B-lymphocytes
  • Follicular dendritic cells (FDCs) fixing antigen on surface (not APCs, no class-II MHC)
  • Macrophages (proper APCs, class-II MHC)
• Interfollicular areas and Subepithelial dome (SED)
  
  • containing mixed-cells, including B-cells, T-cells, Macrophages, Dendritic cells (DCs)

Question 44

Peyer´s Patches (PPs) and associated immune cells (7): the players

• Overview diagram

Answer 44

Question 45

Peyer´s Patches (PPs) and associated immune cells (8) - Lymphocyte homing - Step 1

• … enter peyer’s patch via … … … (HEVs)
• If they recognize antigen coming in from the M-cells at the top of the PP, they get activated and may start …

Answer 45

• B-cells enter peyer’s patch via High Endothelial Venules (HEVs)
• If they recognize antigen coming in from the M-cells at the top of the PP, they get activated and may start proliferating.

Question 46

Peyer´s Patches (PPs) and associated immune cells (9) - Lymphocyte homing - Step 2

• … … …-cells also enter the PP via specialized … endothelial …
• If they encounter a … cell … antigen to them that they recognize, they will begin … and increasing in number.

Answer 46

• Naive CD4 T-cells also enter the PP via specialized high endothelial venules.
• If they encounter a dendritic cell presenting antigen to them that they recognize, they will begin proliferating and increasing in number.

Question 47

Peyer´s Patches (PPs) and associated immune cells (10) - Lymphocyte homing - Step 3

• Some of the T-cells will then most likely … B-cells activated by the same antigen.

Answer 47

• Some of the T-cells will then most likely encounter B-cells activated by the same antigen.

Question 48

Peyer´s Patches (PPs) and associated immune cells (10) - Lymphocyte homing - Step 4

• This is the moment when T-cell/B-cell … takes place: they … each other, T-cells move on to become fully fletched … cells and B-cells undergo Immunoglobulin …-switch to turn into … cells.

Answer 48

• This is the moment when T-cell/B-cell help takes place: they activate each other, T-cells move on to become fully fletched mature cells and B-cells undergo Immunoglobulin class-switch to turn into Plasma cells.

Question 49

Most activated T-cells and B-cells both leave the … … via lymphatic drainage and reach their destination via the blood stream.

Answer 49

Most activated T-cells and B-cells both leave the PP (Peyer’s patchers) via lymphatic drainage and reach their destination via the blood stream.

Question 50

• What is so special about PP is that B-cells are being programmed to produce Ig…
• This happens under the influence of … … and TGF-beta from dendritic cells.
• A lot of data explaining these processes stem from mouse models and research is still going on….

Answer 50

• What is so special about PP is that B-cells are being programmed to produce IgA.
• This happens under the influence of nitric oxide and TGF-beta from dendritic cells.
• A lot of data explaining these processes stem from mouse models and research is still going on….

Question 51

Summary of Mucosal Immunology L1 - P1

• Immune defences in the gut involve mechanical …, entirely non-specific mechanisms and specific mechanisms.
• Accumulations of … tissue along the digestive tube are found in specific, strategic locations (e.g. … patches in the terminal ileum).
• With respect to the adaptive immune response (T-cells, B-cells) , inductive sites are discriminated from effector sites.
• Important inductive sites include the … patches and the … lymph nodes
• The epithelium and lamina … (LP) are effector sites.

Answer 51

• Immune defences in the gut involve mechanical barriers, entirely non-specific mechanisms and specific mechanisms.
• Accumulations of lymphatic tissue along the digestive tube are found in specific, strategic locations (e.g. Peyer’s patches in the terminal ileum).
• With respect to the adaptive immune response (T-cells, B-cells) , inductive sites are discriminated from effector sites.
• Important inductive sites include the Peyer’s patches and the mesenteric lymph nodes
• The epithelium and lamina propria (LP) are effector sites.

Question 52

Summary of Mucosal Immunology L1 - P2

• The dome of a PP is covered in epithelial cells containing many …-cells
• These cells deliver gut … into the PP
• PP’s are specialized induction site giving rise to Ig… producing plasma cells
• It is the presence of … oxide and TGF-… (from DCs) that ascertains that B-cells produce predominantly Ig…
• Naïve B-cells recognize antigen in the presence of follicular … cells (FDCs) in follicles
• T-cells recognize antigen after presentation by … cells (DCs).

Answer 52

• The dome of a PP is covered in epithelial cells containing many M-cells
• M-cells deliver gut antigens into the PP
• PP’s are specialized induction site giving rise to IgA producing plasma cells
• It is the presence of nitric oxide and TGF-b (from DCs) that ascertains that B-cells produce predominantly IgA
• Naïve B-cells recognize antigen in the presence of follicular dendritic cells (FDCs) in follicles
• T-cells recognize antigen after presentation by dendritic cells (DCs).

Question 53

Summary of Mucosal Immunology L1 - P3

• If both B-cells and T-cells proliferate and so increase in number following antigen recognition, their chances of … are higher
• B-cell/T-cell cooperation (mutual …) really gets the immune response going
• T-cells and B-cells leave PPs via afferent lymphatics and return to the gut via the thoracic duct and blood stream. They do not depend on … like naïve T-cells and B-cells
• This cellular recirculation pattern is also referred to as ‘…’

Answer 53

• If both B-cells and T-cells proliferate and so increase in number following antigen recognition, their chances of meeting are higher
• B-cell/T-cell cooperation (mutual help) really gets the immune response going
• T-cells and B-cells leave PPs via afferent lymphatics and return to the gut via the thoracic duct and blood stream. They do not depend on HEV’s like naïve T-cells and B-cells
• This cellular recirculation pattern is also referred to as ‘homing’