Nondiffusional Release of Allergens from Pollen Grains of <i>Artemisia vulgaris</i> and <i>Lilium longiflorum</i> Depends Mainly on the Type of the Allergen

Abstract

Background: Upon contact with a wet surface, mature pollen grains hydrate and release proteins including allergens. Knowledge of the release mechanism of allergens that are mainly localized intracellularly may allow the design of strategies for inhibition of allergen release and the consequent sensitization process. Methods: An improved pollen chromatography was performed with Artemisia vulgaris and Lilium longiflorum pollen. Using three elution media of different pH, osmolality and salt concentration mimicking various types of wet surfaces, the time-dependent elution profiles of total protein, a cell wall-bound acid phosphatase activity (acPase), allergenic (profilin, Art v 1) and nonallergenic molecules (14-3-3 protein, actin) were monitored. Results: The release kinetics of total protein and cell wall-bound acPase followed an exponential decrease in both pollen species indicating a diffusion-based protein release, whereas the elution profiles of profilin, Art v 1 and 14-3-3 protein showed nondiffusion characteristics. No general dependence on pH, osmolality or salt concentration of the elution media was observable in the elution profiles. Under the applied conditions, actin was not released indicating that the pollen grains remained intact during the elution. Conclusion: The elution profiles of pollen allergens indicated that substantial amounts of these proteins do not diffuse from the cell wall or are released from intracellular compartments during imbibitional leakage. Instead, a mechanism seems to operate that involves translocation from the pollen cytoplasm to the extracellular environment by crossing an intact plasma membrane. Such a mechanism would probably allow the use of pharmaceuticals for inhibition of allergen release.

The Distribution of Membrane‐Bound 14‐3‐3 Proteins in Organelle‐Enriched Fractions of Germinating Lily Pollen

“…grains themselves due to unknown mechanisms, as also suggested for pollen allergen release (Hoidn et al, 2005).…”

Walls of allergenic pollen: Special reference to the endexine

“…It is, however, thought that high accessibility of the proteins determines the allergenicity to a significant degree Aalberse et al, 2000;Castells et al, 2002;Hoidn et al, 2005). By comparing pollen of Artemisia vulgaris L. and Lilium longiflorum Thunb., Hoidn et al (2005) found that a fast release of total protein is not restricted to allergenic plants but is a general feature of hydrating pollen.…”

“…It is, however, thought that high accessibility of the proteins determines the allergenicity to a significant degree Aalberse et al, 2000;Castells et al, 2002;Hoidn et al, 2005). By comparing pollen of Artemisia vulgaris L. and Lilium longiflorum Thunb., Hoidn et al (2005) found that a fast release of total protein is not restricted to allergenic plants but is a general feature of hydrating pollen. Since the released proteins have a vital function in the pollen germination and fertilization process these results have to be expected, but they also observed that mugwort pollen released four times more proteins than Lilium pollen (Hoidn et al, 2005).…”

“…By comparing pollen of Artemisia vulgaris L. and Lilium longiflorum Thunb., Hoidn et al (2005) found that a fast release of total protein is not restricted to allergenic plants but is a general feature of hydrating pollen. Since the released proteins have a vital function in the pollen germination and fertilization process these results have to be expected, but they also observed that mugwort pollen released four times more proteins than Lilium pollen (Hoidn et al, 2005). Furthermore Vrtala et al (1993) detected major allergens earlier and in larger amounts in the supernatant of hydrated pollen than minor allergens like profilin.…”

Expression of the major mugwort pollen allergen Art v 1 in tobacco plants and cell cultures: problems and perspectives for allergen production in plants

“…Pollen exudates were prepared according to Hoidn et al (2005). Cell lysates were prepared by freezing leaf or callus pieces in liquid nitrogen and grinding to a fine powder which was transferred into an equal volume of ice cold lysis buffer containing 100 mM sodium phosphate, pH 7.0, 150 mM NaCl, 2 mM ethylene glycol-bis(ß-amino ethyl ether) N,N,N′,N′ -tetraacetic acid (EGTA), 2 mM ethylenediaminetetraacetic acid (EDTA), 2 mM 1,4-dithio- d -threitol (DTT), 0.5 mM 4-(2-amino-ethyl)benzenesulfonyl fluoride hydrochloride (AEBSF), 5 mg l −1 aprotinin and 5 mg l −1 leupeptin, mixed well and centrifuged at 10,000× g for 15 min at 4°C to remove cell debris and larger organelles.…”