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!