Download Immunity of the Mucosa

Toxicology Course Vienna
MODULE 12 Immunotoxicology, Allergy
July 2, 2008
Immunity of the Mucosa
Innate immunity at mucosa
Prof. Erika Jensen-Jarolim, MD
Dept. of Pathophysiology
Medical University Vienna
Gastrointestinaltrakt: Mukosale Pathophysiologie und Immunologie
Jensen-Jarolim, Schöll, Szalai. Springer 2006
Wörterbuch Allergologie und Immunologie, Ferencik, Jensen-Jarolim et al, Springer 2004
Immunologie (Charles A. Janeway and P. Travers)
Absorption of Nutrients - Barrier for Pathogens
Mucus production:
Goblet cells
• Basic secretion
• Lumen:
Secretory fluid defense and Flora
• Sessile: static defense
IEL
Squamous epithelia
• Mobile and recruitable
LC
• Irritant - stimulated secretion: exocytosis of granula
• Asthma: IL-4 and IL-13 bind to IL-4 Rα chain,
but only IL-13 induces Goblet cell hyperplasia, fibrosis
(Kondo et al. American J. of Respiratory Cell and Molecular Biology 2002)
Epithelium:
Langerhans cell (LC),
intraepithelial Lymphocyte (IEL)
Connective Tissue:
DD
MC
plasma cell
Cylindric epithelia
Mast cells (MC),
Dermal Dendrocyte (DD)
• PMNs, Monocytes, Lymphocytes
Fluid phase: Mucous
Mucin glycoproteins (MGs): 30 – 90% carbohydrate with
serin- or threonine-galactosaminyl glycopeptide linkage
Fluid phase: Mucous
Mucin glycoproteins (MGs): 30 – 90% carbohydrate with
serin- or threonine-galactosaminyl glycopeptide linkage
• Lubricating fluid
• Lubricating biofilm
• Protection from physical and chemical harm
• Protection from physical and chemical harm
Mucin-2:
• Prevents colonization and viral infection (HIV, HSV)
by fluid phase carbohydrates
1 – 2 μm layer
Mucin-1 (MG1): bigger
1 – 2 μm layer
• Barrier against toxins, enzymes, acids, carcinogens
• AB0 and Lewis Antigens
• sIgA
• Complexes with Amylase, Prolin-rich-Proteins (PRPs),
Statherin, Histatins
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Endo- und exocrine cells:
participate in mucosal defense
Fluid phase: Serous
Nonspecific immune factors
Paneth cells:
Enterochromaffine cells:
• Lysozyme
• Lactoferrin
„Yellow cells“:
Belong to APUD
PRP: Baxter et al
Biochemistry 1997
• Peroxidase
.
• Histatins:
Histidin-rich α-helical peptides, bacteriostatic activity,
In saliva most important anti-fungal factor (Candida a.),
decrease – HIV infections
• PRPs:
Proline-rich proteins (25 – 40%), bind plantpolyphenols,
- supersaturate saliva with Ca-phosphate
• Cystatins: from Monocytes/Macrophages,
bind bacterial pili – anti-adhesive effect
Specific factor: sIgA
They produce
Serotonin, Gastrin, Secretin,
Somatostatin, VIP,
Enteroglucagon,
Cholecysteokinin.
Lysozyme, Peptidase
α- and β- DEFENSINs :
antimicrobial polypeptides
Contain IgG, IgA
Lysozyme (Muramidase)
• Cationic protein (e.g Parotis: 1-10mg/L)
Defensins
• Cleaves β-1,4-linkage between N-acatylglucosamine & N-acetylmuramic acid
• In vertebrates, invertebrates, plants
• Lyse bacterial cell wall
NAM
NAG
From UCLA-DOE Inst. for
Genomics and proteomics
α-Defensins
β-Defensins
β- pleated sheet
β- pleated sheet, different disulfides
Murein
Cationic antibiotic peptides Cationic antibiotic peptides
Fungicidal and bactericidal activity
against Gram positive bacteria
Origin: neutrophils
Polymerisation
Origin: Paneth cells – mice cryptidins
Lysozyme (Muramidase)
• Binds NAG-NAM structures
• Activity against Gram-positive bacteria
• kills also organisms without peptidoglycan (Fungi) due to cationic nature
Gram positive
Bacillaceae
Lactoferrin: from neutrophils and epithelial cells
• Transferrin family
• Iron-binding glycoprotein (e.g Parotis: 1-10mg/L)
• 10-20 mg/L in saliva, 1g/L (!) in milk
Micrococcaceae
Mycobacteriaceae
Peptococcaceae
Gram negative
Acetobacteriaceae
Gram positive cell wall
• eliminates Fe++, cofactor for bacterial growth
• destabilization of bacterial outer membrane
allows attack by microbicidal peptides
Alcaligenaceae
Bacteroidaceae
Chromatiaceae
Enterobacteriaceae
Legionellaceae
Neisseriaceae
Nitrobacteriaceae
Pseudomonadaceae
Rhizobiaceae
Rickettsiaceae
Gram negative cell wall
Spirochaetaceae
Vibrionaceae
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Facts on gut flora
•
•
We are born sterile
Factors for successful colonization in neonates
Natural sequential colonization
through ingestion – development of imm.system
•
E. c
oli
Bacteroides, anaerobic, 30%
Bifidobacteria, Eubacteriae, anaerobic
E. Coli, facultative anaerobic
•
Breast versus formula feeding
•
Breast milk: undigestable carbohydrates – prebiotics
support bifidabacteria and lactobacilli (probiotics)
•
Adult human body 1 x 10^14 cells
- 10% actually belong to us!!
•
Delivery: Maternal flora (colon, vagina) constitutes principal
child´s flora
•
Colon: > 400 species
density of 1 * 10^11 organism / mL
•
Th2 dominance – counterbalance by bacteria stimulating
TGFβ and IL-10
•
Compete pathogenic populations
by competing for substrates,
unfavorable pH and
Colicins - antibacterial substances.
•
Accelerated IgA response and natural defense
Epithelial cells modulate immune responses
Slow bacterial infection: Helicobacter pylori
bacteria
activated enterozyt / keratinocyte:
1.) H. pylori: damage - danger
– Ion secretion, permeability
– Antigen presentation (MHC I and II)
2.) Insufficient response
– akt. Suppressor T-Zellen
(oral Tolerance)
3.) PMNs: NO, Radicals
– poly-IgR and secretory component
– ICAM Expression and
No elimination,
Langerhans migration
IFNγ, TNFα
– produces IL1, IL-5, IL-6, IL-8, TNF-α
Defense damages mucosa
Gastritis chronical, with limited activity
Mucosal-associated Lymphoid Tissue – MALT
Gut: - GALT, Bronchi: - BALT, Vascular - VALT
Inducer site
Antigen from
Lumen
Villi
intest.
Adaptive immunity at mucosa
67 % of antibody prod.
M-cells
Goblet
0-niveau
MALT
85 % of lymphoid tissue
Lamina
propria
Glandulae intestinales
(Lieberkühn crypts)
Peyers patch
Musc. mucosae
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Mucosal Defense at the effector sites
Epithelia decide where to handle which antigen
small things
Small things
Effector
Big things
Endocytosis
Phagosomes
Lysosomes
Antibodies,
T-lymphocytes
Villi
intest.
B
Goblet
M
T
Epithelial cells:
MHC II Presentation,
but no costimulation
B-cells,macrophages:
HLABII presentation
and costimulation
T
TOLERANCE via Anergy
IMMUNITY or TOLERANCE
0-niveau
Lamina
propria
Peyers
patch
Glandulae intestinales
(Lieberkühn crypts)
Musc. mucosae
Intraepithelial Lymphocytes: IEL
CD8+
• Thymus-independent and dependent T-cells
Pathways for IgA
• 80% CD8+
• 50% bear TCR αα or αβ (TCR-2), 50% γδ TCR (TCR-1)
• γδ-cells differentiate in small intestines
TCR-1
γδ
TCR−2
Vγ Vδ
αβ
αα
Vα Vβ
Vα Vα
Inducer site
•Peyers patch
Cγ Cδ
Cα Cβ
Cα Cα
Mesenteric lymph node:
B-cell maturation and
proliferation
60% B-cells
40% T-cells
• The αα−TCR-2
scans non-classical MHC I on epithelial cells
upon activation – secretory (Leishman et al. Science 2002)
0,4% myeloid cells
• Genito-urinary tract
• Gut
• Salivary and lacrimal glands
• Breasts
• Respiratory tract
• TCR-1: true IEL, dendritic epidermal T-cell (DETC), IL-6 prod.,
participation in wound repair (Jameson et al. Science 2002)
• Participation in attack of viral infections and tolerance ?
IgA: secretory immunoglobulin
Effector sites
• IgA: most prominent isotype in mucosa
• Most produced Ig-class, 2/3 is sIgA
epithelial cell
• Main source bone marrow
poly-IgR
Plasma cell
IgA-dimer
with J-chain
Production (mg/day)
IgA
IgG
Circulation
2100
2100
Saliva
200
2
Tears
5
?
Bile
400
160
Small intestines
5200
600
Large intestines
1200
140
Nasopharynx
45
15
• Antigen transport
Urine
3
3
• Endogeneous reinfection, e.g. EBV
Total
9200
3000
IgA-Dimer
+ secretory
component
Phosphorylation
Endo- and Transcytosis
• IgA secretion - neutralization
with 5 Ig-like domains
Mestecky 1986;
Clin Immunol Immunopathol.
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Fluid phase: Specific Defense
Secretory IgA: Dimer - (2α2L)2,J
Serum IgA: Monomeric – (2α2L)
Bact. IgAspecific proteases
IgA1
Bact. IgAspecific proteases
Disulfide
bridges
Disulfide
bridges
J-chain:
plasma
cells
IgA1
J-chain:
plasma
cells
sc:
polyIgR
Streptococcus sanguis,
S.pneumoniae, Hämophilus
influenzae, Neisseria gon,, N.
mening.
sc:
polyIgR
IgA1: common in serum
mIgA
Extended,
highly
glycosylated
hinge
sIgA
Isotypic and allotypic variation of IgA
IgA Deficiency – defect of immune elimination
IgA2: 50% of IgA in mucosa
Allotypes:
A2m(1) and A2m(2) (98% in caucasians)
Bact. IgAspecific proteases
IgA1
1.) B-cell defects: Bruton – total Ig
2.) selective IgA-deficiency:
1: 800
Functional Adaption:
IgA2 lacks hinge region
(aa 217-241 deleted)
(2α)2,J
2L
• Shortened,
inflexible
hinge,
• Soluble 2L
IgA2
Mucosal immunity in neonates
Colostrom: 2 days
Milk:
~ 5 months
10 – 20 mg/ml sIgA
0,5
mg/ml sIgA
(IgG: 0,3 – 0,5 mg/ml in milk)
Passive
oral immunotherapy
chronic diarrhoea
immune complex diseases
more food allergies
recurrent infections, in respiratory tract and gut:
salmonella, campylobacter, giardia
associated with celiac disease, Crohn´s disease,
Colitis ulcerosa
Vaccination
2 Compartments: peripheral and mucosal immunity
• Antigen handling by lymphnodes – peripheral immunity
Protective IgM, IgG response and cell mediated Immunity
Th1
IL-12
IL-2,
IFNγ
IgG
• by respiratory or gastrointestinal tract - mucosal immunity
Protective IgA antibodies and IEL, but usually tolerance !
Th2 – Th3
TGFβ
IL-4, IL-5,
IL-6, IL-10
IgA
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Oral vaccination
Aim: systemic & mucosal immunity
Toxicology Course Vienna
• Adjuvants: Particles – big things
• Mucosal targeting – functionalization
MODULE 12 Immunotoxicology, Allergy
July 2, 2008
CTB
www.ualberta.ca
LT
www.csb.yale.edu
Immunity of the Mucosa
Prof. Erika Jensen-Jarolim, MD
• Vehicles
Conjugation of antigen to
Cholera Toxin (immunog. any route)
Heat-Labile Enterotoxin of E. coli. (LT)
Expression of antigen in/by
Bacterial vectors, Plants - Edible vaccines
Dept. of Pathophysiology
Medical University Vienna
Gastrointestinaltrakt: Mukosale Pathophysiologie und Immunologie
Jensen-Jarolim, Schöll, Szalai. Springer 2006
Wörterbuch Allergologie und Immunologie, Ferencik, Jensen-Jarolim et al, Springer 2004
Immunologie (Charles A. Janeway and P. Travers)
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