prerequisite for the understanding of basic disease-causing mechanisms and devel-
opment of new approaches in allergy treatment.
The importance of detailed structure analysis was also demonstrated by Halim
et al.^176 in their recent glycoproteomics study of PTMs of seven major allergenic
proteins. Glycan component of glycoproteins may directly be involved in and
promote uptake and target allergens to carbohydrate lectin receptors on antigen
presenting cells or induction IgE antibodies named cross-reactive carbohydrate
determinants. Therefore, a full structural characterization of the glycans on the
natural allergens is a prerequisite for understanding both antibody reactivity and
lectin receptor mediated allergen recognition and modulation of the immune
response. Moreover, detailed characterization of PTMs of allergens is important
for the standardization of allergen products for diagnostic purposes, as well as for
vaccine use.
Modern MS-based proteomics approach offers reliable method for unambiguous
identification of allergens in complex samples.^177 Especially, food allergens^178 are
numerous and heterogeneous, may arise during food processing, be introduced with
GMO ingredients, or introduced during production, thus proteomics that offers high
specificity and sensitivity is a method of choice. Concerning the importance of the
proteomic approach in food allergies and molecular nutritional research, an addi-
tional interesting finding is that endogenously expressed human proteins and
peptides can be used as biomarkers to monitor physiological deregulation and the
effects of food consumption.^179
Alongside advanced understanding of different allergen structures, LC-MS/MS
analysis of cell proteome changes during biological processes (e.g., immunological
disorders such as allergies) may help to understand molecular mechanisms of
allergies. Most proteomic studies of individual players of allergic response have
been done with gel-based proteomic approach. That’s how Bluggel et al.^180 ana-
lyzed proteome of CD4þT cell in pollen allergic and nonallergic subjects demon-
strating the presence of differentially expressed proteins between analyzed groups.
Authors concluded that candidate markers play a role in the context of inflamma-
tion and oxidative stress. However, observed differences are only the beginning of
the story about the role of these proteins in allergy. Although important and large,
these studies incorporate all weakness of gel-based proteomic approach,^181 as well
as common problems of this approach in biomarker discovery (described earlier in
this chapter).
(^176) Halim et al. ( 2014 ).
(^177) Hood et al. ( 2012 ), pp. 2773–2783.
(^178) Cirkovic-Velickovic and Gavrovic-Jankulovic ( 2014 ).
(^179) Sauer and Luge ( 2014 ).
(^180) Bluggel et al. ( 2011 ), pp. 1558–1570.
(^181) Gygi et al. ( 2000 ), pp. 9390–9395.
208 D. Josic ́and U. Andjelkovic ́