1. The document discusses the mucosal immune response to pathogens like H. pylori in the intestinal tract. 2. It describes the innate and adaptive immune effectors in the epithelium, lamina propria, and Peyer's patches that respond to these pathogens. 3. The normal response of the mucosal immune system is tolerance to food antigens to avoid inflammation, but it mounts a strong response to pathogens through IgA antibodies, T cells, and other effectors.

1. Inflammation of the intestinal
mucosa caused by H. pylori
Faculté des Sciences de Tunis
Département de Biologie
realized by:
 Draoui Jihéne
 Abdslem Ghayith
 Saidi Nasreddine:

2. Plan
The interface of the pathogen H.Pylori and the host
immune system
The normal response of the mucosal immune
Ulcer disease
Immune effectors of the intestinal mucosa
Definition
Summary

3. Definition
Inflammation is the body reaction against injury or irritant is not
synonym for infection. Only affects living tissue
Main Types of Inflammation:
Acute
• Rapid onset and of
shorter duration
Chronic
• Slowest onset with
protracted duration

4. Immune effectors of the intestinal mucosa

5. Epithelium:
• enterocytes
• Goblet cells
• Paneth cells
• Intra-Epithelial
Lymphocytes
Lamina propria:
• CD4 + T / T CD8 +
• Plasma IgA +
• DC
• macrophages
• Innate Lymphoid cells
Peyer's patches:
DC
CD4 + T / T CD8 +
B lymphocytes

6. Innate immunity non specific barrier:

7. Mucosal barrier: tight junctions
There are four major types of junctions in
epithelial cells.
Some encircle the cell like a belt,
attaching it to it's neighbors on all sides.
Others are more like 'spot welds' that tie
two cells together at a specific region or
form a tunnel connecting the cytoplasm
of adjacent cells.
Tight junctions also help to distinguish
the apical and baso lateral domains of the
cell by acting as intracellular barriers to
macromolecules and proteins between
these two regions

8. Globet cells mucin Paneth cells α-defensins
There are two types of α-defensins:
DEFA5 and DEFA6 are expressed in
Paneth cells of the small intestine,
where they may regulate and maintain
microbial balance in the intestinal
lumen.
Mucin glycoproteins are thought to play
an important role in protecting the
intestine from chemical or physical injury
but the mechanisms of protection and the
possible relationship between mucin
structure and function are incompletely
understood.

9. Antigen presentation
dendritic cells "M" cells

10. IEL Enterocytes
αEβ7  E-cadherin
Intra epithelial lymphocytes:T CD8 + αβ and γδ T
Strategically located to respond to
antigenic stimulation
Most T-cells are CD8+
Mainly αβ TCR (In mice, γδ TCR
predominates).

11. Innate Lymphoid CellsT γδ, iNKT, LTi-like, NKp46+…
Production of IL-17 and IL-22
Many studies have shown that γ δ T
cells and the IL-17 that these cells
produce are important in early defense
against bacterial infection.
IL-17A and IL-17F play protective roles
in host defense against certain
pathogens at epithelial and mucosal
barriers.
IL-22 is a member of the IL-10
cytokine family, described as having
pro inflammatory activities on liver,
pancreas, intestine and skin.

12. Lamina propria
Lymphocytes T
CD4+
Th17
Plasma IgA + CD4 + T lymphocytes

13. What Is an Ulcer?
An ulcer is a sore, which means it's an open, painful wound. Peptic ulcers are ulcers
that form in the stomach or the upper part of the small intestine, called the duodenum.
Peptic ulcers are actually very common.

14. What Causes an Ulcer?
In 1982, two doctors — Barry Marshall and Robin Warren —
discovered a certain kind of bacteria that can live and grow in the
stomach, Helicobacter pylori (or H. pylori)
The bacterium causes peptic ulcers by damaging the mucous
coating that protects the stomach and duodenum.
Damage to the mucous coating allows powerful stomach acid to
get through to the sensitive lining beneath.
The stomach acid and H. pylori irritate the lining of the stomach
or duodenum and cause an ulcer.
Although H. pylori are responsible for most cases of peptic ulcers,
these ulcers can happen for other reasons, too.

15. What are the symptoms of a peptic ulcer?
•Stomach pain is the most common
symptom of an ulcer.
•It usually feels like sharp aches between
the breastbone and the belly button.
•loss of appetite
•nausea
•burping
•weight loss
•vomiting
•bloody or blackish bowel movements
Emergency Symptoms
•sharp, sudden, persistent, and severe stomach
pain
•bloody or black stools
•bloody vomit or vomit that looks like coffee
grounds
•bleeding—when acid or the peptic ulcer breaks
a blood vessel
•perforation—when the peptic ulcer burrows
completely through the stomach or duodenal
wall
•obstruction—when the peptic ulcer blocks the
path of food trying to leave the stomach

16. How Are Ulcers Diagnosed?
Blood test Urea breath test
Endoscopy Upper gastrointestinal (GI) series

17. In the absence of inflammatory stimuli, the normal response of
the mucosal immune system to foreign antigens is tolerance

18. There are two possible and opposite outcomes of exposure to foreign
antigens entering through the mucosa of the gut.
These are tolerance in the case of food antigens, which is contrasted with
a vigorous antibody and T-cell response after exposure to pathogens.
The essential difference between antigenic challenge by food compared
with that by pathogens is that the pathogens cause inflammation,
whereas food does not.
Both the antigens within food and the antigens within pathogens are
presented by antigen presenting cells to T lymphocytes , but the contexts
in which these two sources of antigen are presented are quite different.
Three different responses of T cells to the presentation of peptides
derived from foods and other antigens delivered via the mucosa may
account for the phenomenon of oral tolerance
The first is the deletion of antigen -specific T cells by the induction of
apoptosis.
The second response is anergy, in which T cells presented with peptide in the absence of co-stimulatory signals
become refractory to further stimulation with antigen
The third response involves the development of regulatory T cells , which can actively suppress antigen -specific
responses following rechallenge with antigen.
1
2
3

19. The interface of the pathogen H.Pylori and the host immune system

20. H. pylori binds to gastric epithelial cells through BabA and
other adhesins.
In strains that carry the Cag pathogenicity island (Cag-PAI), a
type IV secretory apparatus allows translocation of effector
molecules such as CagA into the host cell production of
interleukin (IL)-8 and other chemokines by epithelial cells.
The secreted chemokines lead to the recruitment of
polymorphonuclear cells (PMNs), resulting in inflammation.
CagA might cause disruption of the epithelial barrier and
dysplastic alterations in epithelial-cell morphology.
Tumour-necrosis factor-alpha (TNF-alpha)-mediated apoptosis
may also lead to disruption of the epithelial barrier.
The chronic phase of H. pylori Cytokines produced by
macrophages, particularly IL-12, activate recruited cells such as
helper T cells (TH0, TH1 and TH2) and B cells.
Cytokines also alter the secretion of mucus, which contributes
to H. pylori-induced disruption of the mucous layer, as they
induce changes in gastric-acid secretion and homeostasis.
H. pylori inhibits the host immune response by blocking the
production of (NO) by macrophages and through the ability of
VacA to interfere with the IL-2 signalling pathway in T cells by
blocking transcription of the genes encoding IL-2 and IL-2R
1 2
3 4
5
6
6

21. The key distinction between
tolerance and the development of
powerful protective adaptive
immune responses is the context
in which peptide antigen is
presented to T lymphocytes in
the mucosal immune system.

22. Summary
Mucosal immune system needs to selectively respond to pathogens
Humoral immune response is IgA dominated.
Unique lymphocyte repertoire and cytokine environment limit
inflammation

23. Thank you for your
attention

24. references
• http://www.bio.davidson.edu/people/kabernd/berndcv/lab/epithelialinfoweb/Tight%20Junctions
.html
• http://www.biocarta.com/Catalog.aspx?cid=35045&mid=-1
• http://cochin.inserm.fr/Departements/ih/equipe-bomsel
• http://sciencedesprobiotiques.ca/les-bacteries-et-votre-sante/systeme-de-defense-de-
lorganisme/les-trois-lignes-de-defense/
• http://blog.therabreath.com/tag/helicobacter-pylori/
• https://microbewiki.kenyon.edu/index.php/Gastritis_and_Peptic_Ulcer_Disease_Caused_by_Heli
cobacter_pylori
• http://www.nature.com/nrmicro/journal/v2/n9/fig_tab/nrmicro955_F3.html
• http://www.nature.com/nrm/journal/v2/n6/fig_tab/nrm0601_457a_F1.html
• http://www.nature.com/mi/journal/v5/n1/full/mi201155a.html
• http://www.ncbi.nlm.nih.gov/books/NBK27169/
• http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/I/Inflammation.html