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Presentation by Lars Harder Christensen, PhD

The role of the IgE repertoire in allergic disease

Lars Harder Christensen

Research Scientist, PhD ALK, Hørsholm, Denmark


Presentation by Lars Harder Christensen, PhD

Allergic individuals are differently sensitized‌.

‌.and therefore have different IgE repertoires


Presentation by Lars Harder Christensen, PhD

The IgE repertoire mainly develops in the local nasal- and bronchial mucosa

Pollen

Allergen

Flower

• Ab class switching to IgE • Affinity maturation Plant (Ambrosia artemisiifolia)

• Clonal expansion

Cameron et al., JI, 2003; Coker et al., JI, 2003; Takhar et al., JI, 2005; Takhar et al., JACI, 2007; and several more….


Presentation by Lars Harder Christensen, PhD

IgE is a key player in allergic disease Allergic sensitization – Development of allergen-specific IgE antibodies


Presentation by Lars Harder Christensen, PhD

IgE is a key player in allergic disease Immediate allergic reaction – degranulation of effector cells


Presentation by Lars Harder Christensen, PhD

IgE is a key player in allergic disease Immuno-modulatory actions of basophils


Presentation by Lars Harder Christensen, PhD

IgE is a key player in allergic disease Facilitated Allergen Presentation (FAP)


Presentation by Lars Harder Christensen, PhD

Creation of well characterized, recombinant IgE antibodies

Der p 2 allergen Dermatophagoides pteronyssinus

31 monoclonal recombinant IgE antibodies specific for Der p 2

Christensen et al., J Allergy Clin Immunol, 2008 and Christensen et al., J Immunol, 2010


Presentation by Lars Harder Christensen, PhD

Characterization of recombinant IgE antibodies: Epitope mapping using rDer p 2 mutants

2D model

Christensen et al., J Allergy Clin Immunol, 2008


Presentation by Lars Harder Christensen, PhD

Characterization of recombinant IgE antibodies: Affinity for rDer p 2 (KD in nM)

IgE affinity for Der p 2 1000

High affinity

Medium affinity

Low affinity

100

10

1

0.1

0.01

Name of rIgE clone

Christensen et al., J Allergy Clin Immunol, 2008


Presentation by Lars Harder Christensen, PhD

Model system for investigation of effector cell degranulation


Presentation by Lars Harder Christensen, PhD

100

80

3 IgE

60

2 IgE

40

20

0 0,001

0,01

0,1

1

10

100

ng/ml rDer p 2 Affinity for rDer p 2 (KD in nM)

% Degranulated Basophils (CD63)

Effect of IgE-clonality

1000 100

High affinity

Medium affinity

Low affinity

10 1 0.1 0.01

Christensen et al., J Allergy Clin Immunol, 2008


Presentation by Lars Harder Christensen, PhD

Model system for investigation of facilitated allergen presentation

Facilitated Antigen Binding assay (Surrogate FAP assay):

Correlates well with T-cell activation


Presentation by Lars Harder Christensen, PhD

Conclusion • The IgE repertoire is complex and consists of several distinct factors that directly affects important mechanisms of allergic disease. • This high complexity of the IgE repertoire may partly explain why e.g. different patients having the same IgE titer may show different levels of symptoms. • A greater understanding of the IgE repertoire and how it affects important mechanisms of allergy may eventually lead the way to improve future diagnostic tests and prediction of SIT outcome, based on individual IgErepertoire compositions.


Presentation by Lars Harder Christensen, PhD

Acknowledgements ALK colleagues            

Jens Holm Kaare Lund Gitte Lund Nicholas Willumsen Peter A. Würtzen Caroline Bolwig Oscar Duffort Jette Skovsgaard Gitte Grauert Gitte Koed Annette Giselsson Chunqing Zhang

Danish University of Pharmaceutical Sciences  Jan Engberg  Erik Riise  Lærke Bang


Presentation by Lars Harder Christensen, PhD

Thanks for your time and attention!

Lars H Christensen