Trained immunity

A memory for innate host defense

Simone J.C.F.M. Moorlag, MSc, MD

PhD candidate Radboudumc Promotor: Mihai G. Netea Virology course Rotterdam 30 May 2018

Innate versus specific immunity

Dranoff, 2004

Innate immunity: - rapid - not-specific, indiscriminate

- lacks immunological memory

Adaptive immunity: - needs 10-14 days - a specific activation against a particular microorganism, enhancing the effectivity of the response - builds immunological memory

Holometa-bolous

Annelids

Molluscs

Insects

Heterometa-bolous

Urochordates Echinoderms

-800 My

-450 My

Gnathostomes

Fishes Amphi- bians

Reptiles Birds

95% Innate

5% Innate and Adaptive

Plants

-1 By

Memory: the ability of a system to store and recall information on previously encountered characteristics

Agnathans

Mammals

Placoderms

Systemic acquired resistance

Do insects have immunological memory?

Increased response to secondary infection

Netea et al: Cell Host and Microbe 2011

Innate immune memory also present in vertebrates?

Low dose of C. albicans

PBS

Priming 7 days Secondary exposure

Lethal dose C. albicans

Outcome?

Innate memory in mice: model

Innate immunity-dependent protection in mice

Quintin et al, Cell H&M, 2012

Trained immunity

In-vitro preincubation model

PBMCs/Monocytes 1st stimuli

Day 0

Wash-out 1st stimuli

Day 1 Cytokine analysis

2nd stimuli

Day 6

37°C

Resting time

ELISA

Quintin et al, Cell H&M, 2012

membrane phospholipid bilayer, with intercalated ergosterol molecules and enzyme proteins

mannan

protein

1:6 glucan

1:3 glucan

chitin

cell w

all

Fungal cell envelope: target for polyenes, echinocandins, nikkomycins

The Candida albicans cell wall

NF-B

Raf-1

Dectin-1

Syk

CARD9

P

1st challenge =

priming C. albicans

cytokines

-glucans 2nd challenge

Enhanced secondary response to Candida

0

2

4

6

8

10

12

Total TB deaths

% m

ort

alit

y

BCG-

BCG +

Introduction of BCG in Sweden, 1927-31: Mortality at 0-4 years- 20,000 children

BCG → 50% reduction in mortality

Naeslund, Rev de la Tuberculose, 1931

Non-specific effects of BCG: reduced mortality

3 RCT’s: 38%↓

Shann, Arch. Dis. Child, 2010

32-53%↓

34-40%↓ 12-48%↓

BCG-Induced Trained Immunity

Kleinnijenhuis et al. PNAS, 2012 Netea et al. Science, 2016

BCG enhances monocyte-derived cytokines

Kleinnijenhuis et al, PNAS, 2012

BCG effect on epigenetics and transcription

Kleinnijenhuis et al, PNAS, 2012

Low gene expression Increased gene expression

Tolerance

Saeed, Quintin et al, Science, 2014

What are the pathways distinguishing Training vs Tolerance ?

metabolism

signaling

Saeed, Quintin et al, Science, 2014

What are the pathways distinguishing Training vs Tolerance ?

Warburg effect:

A metabolic switch

- Switch from oxidative phosphorylation -> glycolysis - Results in more lactate and faster production of ATP

Trained immunity:

Arts et al, 2016, Seminars in Immunology

Model of metabolic activation in TRIM

Innate memory responses

Netea et al. Science, 2016 Quintin J et al. Cell Host & Microbe, 2012

Histone modifications

Altered cellular metabolism

Initial stimulus (infection/vaccination)

Training programs

1st infection 2nd infection

time

2nd infection

Tolerance programs

1st infection

time

1) Does BCG induce epigenetic changes at a genome wide level? 2) Can we demonstrate the impact of BCG in a model of human infection?

BCG-Induced Trained Immunity

0.5

1

BCG induced genome wide histone modifications

• ChIP-sequencing • H3K27ac changes in monocytes of 7 volunteers

Arts and Moorlag et al. Cell host and Microbe, 2018

Several important signaling and inflammatory related pathways upregulated

- EGFR, VEGF, FGF, cytokines and chemokines

- PI3K-Akt

Pathway analysis of H3K27ac changes

Arts and Moorlag et al. Cell host and Microbe, 2018

BCG induces enhanced cytokine responses

Arts and Moorlag et al. Cell host and Microbe, 2018

Impact of BCG in a model of human infection

Arts and Moorlag et al. Cell host and Microbe, 2018

Induction of IL-1β correlates with YF viremia

Arts and Moorlag et al. Cell host and Microbe, 2018

• BCG vaccine induces genome wide epigenetic changes

→ functional changes in signaling and inflammatory pathways

• BCG protects against a viral human experimental infection

→ induction of IL-1β is the most reliable correlate of this protection

• IL-1β is a crucial mediator of trained immunity

Conclusions

Trained immunity induces Functional Reprogramming of Myeloid Precursor Cells

Christ et al. Cell, 2018

Innate memory in health & disease

Training programs

Tolerance programs

• Innate immunity maturation • Nonspecific protection by vaccines - e.g. BCG vaccine

• Mucosal tolerance • Limitation of tissue damage in infection

• Contributes to hyperinflammation: - atherosclerosis - reumatoid artritis - diabetes

Training programs

Tolerance programs

• Immune paralysis in sepsis

Siroon Bekkering et al. Arterioscler Thromb Vasc Biol.

2014;34:1731-1738

Trained immunity and atherosclerosis

Applications

• Trained immunity as a new strategy to modulate levels of IL-1:

1) enhance IL-1 responses to improve bone marrow recovery

• Boost the immune system of young children and elderly people

2) inhibition of trained immunity in IL-1 driven autoinflammatory diseases

• Improve vaccination responses

Effect of BCG on influenza vaccination (1)

• Influenza-related morbidity and mortality remain high

• Seasonal vaccination is the backbone of influenza management but does

not always result in protective antibody titers

• Nonspecific effects of BCG vaccination

• Could BCG vaccination could also enhance immune responses to influenza vaccination?

Leentjens et al., J Infect Dis. 2015

Methods

Healthy volunteers received: - live attenuated BCG vaccine (n = 20) or placebo (n = 20) in a randomized fashion - trivalent influenza vaccine 14 days later

Outcome: - Hemagglutination-inhibiting (HI) antibodies - ex vivo leukocyte responses

Leentjens et al., J Infect Dis. 2015

BCG enhances HI antibody responses

In BCG-vaccinated subjects: enhanced HI antibody responses against the 2009 pandemic influenza A(H1N1) vaccine strain

Trend toward more-rapid seroconversion

Nonspecific effects of influenza vaccination

Before vs after influenza vaccination Before vs after BCG vaccination

• Modulation of cytokine responses against unrelated pathogens

Acknowledgements

University of Groningen Vinod Kumar Yang Li Cisca Wijmenga

Radboudumc Rob Arts Boris Novakovic Chantal Reusken Marion Koopmans Marije Doppenberg Leo Joosten Hendrik Stunnenberg Reinout van Crevel Mihai Netea