chapter  3
86 Pages

Chapter Methods for Detection of Food Allergens

Protein and Allergen Analysis........................................................... 102 3.1.4 Applicability of Other Analytical Methods ....................................... 103

3.1.4.1 Microarray-Based Proteomics ........................................... 104 3.1.4.2 Miniaturization of Protein Arrays ...................................... 105 3.1.4.3 Aptamers and Aptazymes in Molecular

Diagnostics and Biosensors ............................................... 106 3.1.4.4 Atomic Force Microscopy ................................................. 106

3.1.5 Conclusions ....................................................................................... 107 References .............................................................................................................. 107 3.2 Animal Models in Food Allergen Analysis and

Investigating the Mechanisms of Allergy ..................................................... 114 3.2.1 Introduction ....................................................................................... 114 3.2.2 Important Criteria for Animal Models for Food Allergy .................. 115 3.2.3 Animal Models to Predict the Potential

Allergenicity of Proteins ................................................................... 116

3.2.3.1 Predictive Food Allergy Models in Brown Norway Rats ........................................................... 116

3.2.3.2 Predictive Food Allergy Models in Mice ........................... 118 3.2.3.3 Predictive Food Allergy Models in Guinea Pigs ................ 119 3.2.3.4 Predictive Food Allergy Models in Dogs ........................... 119

3.2.4 Mechanistic and Therapeutic Animal Models for Food Allergy Research ...................................................................... 120 3.2.4.1 Mechanistic and Therapeutic Models in Mice ................... 120 3.2.4.2 Mechanistic Models in Pigs ............................................... 122

3.2.5 Conclusions and Future Trends ........................................................ 122 References .............................................................................................................. 123 3.3 Clinical Methods for the Diagnosis of Food Allergies ................................. 127

3.3.1 Medical History ................................................................................ 129 3.3.2 Food Diary ........................................................................................ 130 3.3.3 Physical Examination ....................................................................... 131 3.3.4 Diagnosis of IgE-Mediated Food Allergy ......................................... 131

3.3.4.1 Prick Skin Tests ................................................................. 132 3.3.4.2 Blood Tests ........................................................................ 133

3.3.5 Diagnosis of Non-IgE-Mediated Food Allergy ................................ 134 3.3.6 Atopy Patch Test ............................................................................... 134 3.3.7 Challenge Testing ............................................................................. 136

3.3.7.1 Diagnostic Elimination Diet .............................................. 136 3.3.7.2 Oral Food Challenge .......................................................... 137

3.3.8 Other Tests: Non-IgE and Nonimmunological Adverse Food Reactions ................................................................... 141

3.3.9 Future Diagnostic Perspectives ......................................................... 143 References .............................................................................................................. 144 3.4 Methods for Structural Determination and Epitope Mapping

of Food Allergens .......................................................................................... 146 3.4.1 Introduction ....................................................................................... 146 3.4.2 Physicochemical Characterization of Food Allergens ...................... 146

3.4.2.1 Mass Spectrometry ............................................................ 146 3.4.2.2 Secondary Structure Determination ................................... 148 3.4.2.3 Investigation of Protein Aggregation ................................. 149 3.4.2.4 Nuclear Magnetic Resonance ............................................ 150 3.4.2.5 X-Ray Crystallography ...................................................... 151

3.4.3 B Cell Epitope Mapping of Food Allergens ..................................... 153 3.4.3.1 Linear IgE-Binding Epitopes ............................................. 154 3.4.3.2 Conformational IgE Epitopes ............................................ 157 3.4.3.3 Future Approaches by Hydrogen and

Deuterium Exchange .......................................................... 158 3.4.3.4 In Silico-Based IgE Epitope Prediction ............................. 158

3.4.4 Mapping T Cell Epitopes of Food Allergens .................................... 159 3.4.4.1 Technical Approach ........................................................... 159 3.4.4.2 T Cell Epitopes of Class 1 Food Allergens ........................ 160

3.4.4.3 T Cell Epitopes of Class 2 Food Allergens ........................ 162 3.4.4.4 In Silico Analysis of T Cell Epitopes ................................. 163

3.4.5 Concluding Remarks ........................................................................ 163 References .............................................................................................................. 163

Allergenic hypersensitivity is a multi-organ response, which involves the occurrence of various clinical manifestations causing discomfort (see Chapter 1) and can be mistaken for other illnesses. Thus, correct diagnosis is of utmost importance. Avoiding allergenic hypersensitivity largely depends on the patient, who should assess health hazards, i.e., recognize potential allergens in his or her diet.