Pollen associated lipid mediators

Messenger substances from pollen with proinflammatory and immunomodulatory effect on cells of allergic inflammation.

In a humid environment, pollen not only releases allergens but also various lipid mediators. These pollen-associated lipid mediators are also called PALMs. PALMS show different pro-inflammatory effects especially on cells of the allergic immune response, including chemotactic effects on human neutrophil or eosinophil granulocytes. The analysis of lipids in aqueous pollen extracts revealed various products of polyunsaturated fatty acids (linoleic and α-linolenic acid), which also have an activating effect on human granulocytes.

In addition to these pro-inflammatory PALMs, pollen extracts contain another group of lipid mediators with immunomodulating effects. These lipids are autooxidation products of alpha-linolenic acid with prostaglandin ring structures(phytoprostanes).

In summary, the release of the immunomodulating PALMs at the site of pollen exposure leads to an enhancement of the specific allergen response by the sensitizing pollen extracts.

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