Cathryn Nagler University of Chicago Department of ... · [email protected] Largest area of...

Mucosal Immunology

Cathryn NaglerUniversity of Chicago

Department of Pathology/Committee on [email protected]

Largest area of contact of the immune system with the environment.

Largest accumulation of lymphoid tissue in the body:6 x 1010 antibody forming cells in mucosal tissues vs

2.5 x 1010 in lymphoid organs.

The gut associated lymphoid tissue (GALT) contains more lymphocytes than all of the secondary lymphoidorgans combined!

Secretory IgA is produced at a rate of 40-60 mg/kg/day.

Mucosal surfaces are the majorportals of entry for antigen

Advanced Course in Basic & Clinical Immunology February 20, 2018

1

Antigens enter through mucosal surfaces

From Nagler-Anderson, Nat.Rev. Immunol. 2001, 1:59

Lymphoid cells protect epithelial barriers at mucosal surfaces

From Gerald Pier, Channing Labs, HMS


2

Peyer’s patch (inductive)

Villus epithelium and lamina propria (effector) (effector)

The gut-associated lymphoid tissue contains both inductive and effector sites

From Nagler-Anderson, Nat.Rev. Immunol. 2001, 1:59

Barker, N., Nat. Rev. Mol. Cell Bio. 2014, 15: 19

The intestinal epithelium is self-renewing

Small intestine

Colon


3

1. Mucus2. Anti-Microbial Peptides3. Intercellular tight junctions that restrict the

passage of even very small (2kD) molecules between cells

4. Secretory IgA

Specialized protective adaptations ofthe intestinal epithelial barrier

Johansson MEV and Hansson, GC Nat. Rev. Immunol. 2016, 16: 639

Mucus layers in the small intestine and colon


4

Anti-microbial peptides protect the intestinal epithelial barrier

Gallo, RL & LV Hooper Nat. Rev. Immunol. 2012, 12: 503

Anatomy of the mucosal barrier: the intestinal epithelial junctional complex

Turner, J.R. Nat. Rev., Immunol. 2009, 9:799


5

Clayburgh, DR, Shen, L & Turner JR. Lab Invest. 2004, 84: 282

The epithelial tight junction regulates mucosal homeostasis

Turner, J.R. Nat. Rev., Immunol. 2009, 9:799


6

Secretory IgA

IgA (not IgG) is the major isotype of Ig synthesized by the body!At least 80% of all plasma cells are located in the intestinal lamina propria and together produce more IgA than all other Ig isotypes combined. Class switching to IgA is regulated by TGF-.

J chain joins IgA monomers

Secretory component (SC) prevents proteolytic damage to secretory IgA in the harsh luminal

microenvironment.



7

IgA binds to the polymeric Ig receptor (pIgR, also known as transmembrane SC) on the basolateral surface and is transported to the apical surface. The portion of thepIgR attached to the Fc region of IgA is then enzymatically cleaved and stays bound to dimeric IgA as secretory component.


Transport of secretory IgA to the luminal surface

Secretory IgA has several functions at epithelial surfaces


8

Mechanisms of antigen sampling in the small intestine

Schulz, O & Pabst. O Trends Immunol 2013, 34: 155

APC (DC or macrophage)

Lymphocyte recruitment requires specific chemokine recognition and appropriate adhesion/homing receptor engagement

From Kunkel and Butcher, Nat. Rev. Immunol. 2003, 3: 822

IgA ASCs induced insmall intestine can enterall mucosal sites. ASCsinduced in the respiratorytract lack 47 and CCR9and are restricted to non-intestinal mucosal tissuesand the bone marrow.


9

The chemokine CCL25 (also calledthymus expressed chemokine, TECK)is secreted only by epithelial cells in thethymus and the small intestine, and attracts developing CCR9+ Tcells to these sites.

The dual expression of the intestinalhoming receptor 47 (an integrin which binds the mucosal vascular addressin MADCAM-1) and CCR9 allowsfor the selective homing of memory Tcells to the intestinal lamina propria.

Chemokine/receptor pairs regulate tissuespecific migration

From Cheroutre and Madakamutil, Nat. Rev. Immunol. 2004, 4: 290

Enzymatically converted vitamins control lymphocytemigration in the skin and the gut

From Mebius, Nat. Immunol 2007, 8: 229

Dendritic cells (DCs) in the GALT express enzymes required for converting dietary vitamin A to retinoic acid (RA). T cell activation in the presence of retinoic acid induces the expression of the gut homing receptors CCR9 and 47.

DCs in the skin convert sunlight induced vitamin D3 to its active form 1,25(OH)2D3, which induces the expression of CCR10 on activated T cells, allowing their migration into the epidermis.


10

Memory T effector cells accumulate in the intestinal lamina propria, enabling the GALT to respond quicklyand effectively to challenge with enteric pathogens.

Antigen challenge redistributes memory T effectorcells to “man the barrier” for strategicmucosal defense

Memory T cells accumulate in the GALT

Atypical populations of T cells that reside between enterocytes above the basement membrane.

Express CD8 as a CD8homodimer (rather than the CD8 heterodimer expressed by CD8+ T cells at othersites)

Many IEL are constitutivelycytolytic directly ex vivo.

A large proportion of IEL bear (as opposed to ) T cell receptors.

Intestinal intraepithelial lymphocytes

From Karen Edelblum, U. Chicago


11

IEL act as sentinels to detect and repair damaged epithelium

-TCR+

From Cheroutre and Madakamutil, Nat. Rev. Immunol. 2004, 4: 290

lumen T cell nuclei

Edelblum et al PNAS 2012, 109: 7097

How does the gut associated lymphoid tissue distinguish

innocuous dietary antigens and commensal bacteria from

pathogenic microbes….and mount an appropriate

response to each?


12

Oral tolerance- induction ofmucosal and systemic non-responsiveness to orally-administered antigens

Orally administered antigen ameliorates diseasein a large variety of experimental models

Weiner, H. et al Immuno. Rev. 2011; 241:241


13

A multistep model of oral tolerance to dietary antigens

I. Antigen loaded CD103+

DC migrate to MLN II. RA produced by DC and

stromal cells in MLN induce homing receptors and favor TGF- dependent conversion of Foxp3+

TregsIII. Committed Tregs home

back to LP IV. Tregs expand under the

influence of IL-10 produced by CX3CR1hi

macrophagesV. Some Tregs exit mucosa

via lymph or blood-stream to promotesystemic tolerance

Pabst and Mowat, Mucosal Immunology 2012, 5: 232

Tolerance to dietary antigen requires the induction of a bacteria-induced barrier protective response

Stefka, Feehley et al PNAS 2014, 111; 13145


14

Mucosal (oral/nasal) vaccines are the preferred method for vaccination in the developing world.

Mucosal vaccines are easily administered (needle-free), non-invasive and cost-effective.

Only mucosal vaccination elicits a protective secretory IgA response.

Mucosal Vaccines

Mucosal vaccination routes and compartmentalization of effector functions

Lycke, N. Nat. Rev. Immunol. 2012, 12; 592


15

Currently licensed mucosal vaccines

Kim, S.-H. and Jang, Y.-S. Clin. Exp. Vaccine Res 2017, 6: 15

Intranasal vaccination stimulate immune responses inthe nasopharynx-associated lymphoid tissue

Lycke, N. Nat. Rev. Immunol. 2012, 12; 592


16

Adjuvants that are effective parenterally are generally toxic or unstable when given orally.

The tendency of the GALT to induce tolerance to solubleantigens has made identification of effective mucosal adjuvants difficult.

Microbial products such as cholera toxin, E. coli heat-labiletoxin and oligodeoxynucleotides containing a bacterial CpG motif can act as effective mucosal adjuvants and induce both mucosal and systemic immune responses to co-administeredprotein antigens.

Mucosal adjuvants

Pattern recognition receptors and their cellular location


17

Capsule

Bacterial TLR ligands

Pathogenic bacteria use various strategies to trigger a proinflammatory program in intestinal epithelial cells

From Sansonetti, Nat. Rev.Immunol. 2004, 12:953


18

Commensal bacteria populate our skin and mucosal surfaces and profoundly influence our health

0

1.2E+14

Human cells Bacterial cells

10 trillion human cells20,000 genes

100 trillion bacterial cells2 -20,000,000 genes

There are as many E. coli in our gut as there are people on earth!

We exist in a dynamic interrelationship with our commensal microbiome!

Healthy individuals “tolerate” their intestinal microbiota but are also constantly receiving signals from the microbiome that have a profound impact on both systemic and mucosal immunity.


19

The commensal microbiota confers manyhealth benefits to the host

The 16S rRNA gene is highly conserved among bacterial species.

“Universal” primers target conserved regions of this gene and allow for amplification and sequencing of species specific hypervariable regions for bacterial classification.

Structure of 16S ribosomal RNA

Culture independent methods of analysis have transformedour understanding of the composition of the microbiome


20

The composition of the microbiota varies by anatomical site

Cho, I. & Blaser, M.J. Nat. Rev. Genetics 2012; 13: 260

Dominguez-Bello, MG et al, Gastroenterology 2011; 140:1713

The gastrointestinal microbiota changes throughout life


21

The atopic march


22

Allergic responses to food can be diverse and can include life-threatening anaphylactic shock (respiratory/cardiovascular collapse)

The prevalence of eosinophilic esophagitis (EoE), a foodrelated disease is also increasing


23

Antibiotic use

Westernhigh fat,low fiberdiet

Elimination of entero-pathogens(H. pylori, helminths)

Vaccination/reduced exposure toinfectiousdisease

Caesarean birth/formula feeding

Alteration ofcommensalmicrobiota“dysbiosis”

geneticallysusceptibleindividual

Inflammatory Bowel Disease

Obesity

Food Allergy

Diabetes

Autism

Asthma

Feehley et al Seminars in Immunopathology 2012, 34; 671

“Diseases of WesternSociety”

Germ free mice are a powerful tool to examine the role of the commensal microbiota in the regulation of health and disease


24

Protection against allergic sensitization to food requires the induction of a bacteria-induced barrier protective response

Stefka, Feehley et al PNAS 2014, 111; 13145

Can we develop novel strategies to modulate the composition of the microbiota to prevent or treatfood allergies?


25

Evaluation of dietary management of cow’s milk allergy

Visit 1

• Full anamnestic and clinical evaluation

• SPT and APT• Oral food challenge (OFC)

Visit 26 months

• Full clinical evaluation

Visit 312 months

• Full clinical evaluation• SPT and APT• Oral food challenge (OFC)

Berni Canani R, et al. The Journal of Pediatrics 2013, 163; 771

0

20

40

60

80

100

EHCF EHCF + LGG RHF SF AAF

% o

f ch

ildre

n a

cqu

irin

g t

ole

ran

ce a

fter

12

mo

nth

s

Berni Canani R, et al. The Journal of Pediatrics 2013, 163; 771

Supplementation of extensively hydrolyzed casein formula (EHCF)with Lactobacillus GG accelerates acquisition of tolerance

in children with cow’s milk allergy

P<0.001 P<0.001P<0.001

P<0.001


26

The cow’s milk allergic (CMA) infant microbiome exhibits significantly increased diversity

Berni Canani, Sangwan, Stefka et al ISMEJ 2016, 10; 742

The composition of the fecal microbiota is altered in cow’s milk allergic (CMA) infants


Healthy

n=20

Cow's Milk Allergic

n=20

LactobacillalesBifidobacterialesEnterobacterialesBacteroidalesBurkholderialesPasteurellalesOther

Clostridiales


27

Treatment with LGG supplemented formula changes microbial community structure to enhance production of

of fecal butyric acid and promote tolerance to CMA

Tolerance to CMAat 12 months

EHCF 0/7

EHCF + LGG 5/12*


IL-22

food

modified fromM. Velasquez-Manoff,Nature 2015, 518: S4


28

Are mice colonized with a healthy microbiota protected against an allergic response to food?

Healthy infantmicrobiota

Cow’s milk allergic (CMA) infant microbiota

Sensitize with lactoglobulin (BLG)/CT

Non-allergic

Allergic

Transfer of a healthy infant microbiota protects against an anaphylactic response to sensitization with BLG+CT

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70-10

-8

-6

-4

-2

0

Healthy Colonized

Allergic Colonized

50mg BLGgavage

50mg BLGgavage

* * * * * *

†=3

Time (min.)

T °

C

Healthy CMA0

10

20

30

40 *

BL

G-s

pe

cific

IgE

(ng

/mL

)

Feehley, Plunkett et al, 2018, in revision


29

Healthy infantmicrobiota

Cow’s milk allergic (CMA) infant microbiota

Sensitize with lactoglobulin (BLG)/CT

Non-allergic

Allergic

Developing microbiome-modulating therapeutics to prevent or treat food allergy

www.clostrabio.com

• Drug formulations from microbial metabolites


30

Cathryn Nagler University of Chicago Department of ... · [email protected] Largest area of...

Documents

Transcript of Cathryn Nagler University of Chicago Department of ... · [email protected] Largest area of...