Arachidonic acid metabolism in alveolar macrophages from actively sensitized guinea-pigs: effects of sensitization and specific allergen.
Arachidonic acid (AA) metabolism, including mediator release and lipid turnover, was explored in [3H]AA-radiolabelled alveolar macrophages obtained from guinea-pigs actively sensitized to ovalbumin (sAM) and controls (cAM). The basal and allergen-induced AA metabolism of cAM and sAM were examined in the presence and absence of homologous serum obtained from the same control or sensitized animals. Basal AA metabolism of cAM and sAM involved the release of lipoxygenase and cyclooxygenase [3H]metabolites and free [3H]AA into the culture medium. However, in sAM, the production of free [3H]AA was significantly lower than in cAM. The allergen had no effect on the basal AA metabolism of cAM and sAM or on the metabolism of cAM and sAM cultured in the presence of control serum. In contrast, it increased the [3H]LTC4-D4 and free [3H]AA production of sAM cultured with sensitized serum but not those of cAM cultured with the same sensitized serum. In sAM, the allergen effect disappeared when the sensitized serum was heated for 1 h to 56 degrees C. Our results suggest that two factors, both induced by the active sensitization of guinea-pigs, one in the serum and one on the macrophages obtained from sensitized guinea-pigs, are required for the allergen to have an impact on the AA metabolism of alveolar macrophages in increasing the production of 5-lipoxygenase metabolites.
Laboratoire de la Signalisation et de la Différenciation des Macrophages, INSERM CJF 9107, Bâtiment L1, Hôpital de Rangueil, Toulouse, France.
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C
M'Rini
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B
Pipy
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Rami
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JP
Besombes
D000485:Allergens / Q000494:pharmacology*; D000818:Animals; D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism; D016718:Arachidonic Acid / Q000378:metabolism*; D001769:Blood; D002478:Cells, Cultured; D003470:Culture Media; D006168:Guinea Pigs; D006358:Hot Temperature; D007114:Immunization; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008563:Membrane Lipids / Q000302:isolation & purification; D014316:Tritium
D000485:Allergens; D003470:Culture Media; D008563:Membrane Lipids; D014316:Tritium; D016718:Arachidonic Acid; D001094:Arachidonate 5-Lipoxygenase