Fig. 2
From: Initiating pollen sensitization – complex source, complex mechanisms
The composition of the pollen matrix influencing the sensitizing potential of allergenic pollen sources. The intrinsic part consists of compounds inherent to the pollen and the extrinsic fraction, includes a prominent microbiome retaining diverse bacterial strains, viruses and fungi. Major immune stimulators can be proteins including allergens with intrinsic adjuvant activities, non-allergenic proteases, but also lipids and metabolites such as PALMS, adenosine and flavonoids. Additionally, climate and exposure to air pollutants shape the composition of the pollen matrix. Details on the immunomodulatory activities of pollen matrix-derived components as well as on the modulation of the matrix composition can be found in Tables 2 and 3. PALMs, pollen-associated lipid mediators; CO2, carbon dioxide; NO2, nitrogen oxides