Regulation and kinetics of platelet-activating factor and leukotriene C4 synthesis by activated XXXX basophils.

@entity1 @entity5038 @entity2426 @entity4443 @entity4515 @entity56 @entity2772 @entity141 @entity5567
BACKGROUND: @entity56 is the result of an interplay of many different cell types, including basophils and mast cells, in combination with various inflammatory lipid mediators, such as platelet-activating factor ( @entity5567 ) and @entity4443 (LT). LTC4 synthesis by @entity1 basophils has been studied quite extensively. However, not much is known about the synthesis of @entity5567 by @entity1 basophils. OBJECTIVE: In this study, we have made a comprehensive comparison between the kinetics of @entity5567 and LTC4 synthesis, in highly purified basophils, activated with different stimuli or with combinations of stimuli. METHODS: Synthesis of @entity5567 and LTC4 by @entity1 basophils was determined with commercially available assay kits. The basophils were activated with C5a, @entity5038 , @entity4515 , allergen or anti-IgE, in the absence and presence of @entity2772 and/or in combination with elevation of cytosolic free @entity141 by the sarcoplasmic reticulum @entity141 -ATPase inhibitor @entity2426 . RESULTS: Most stimuli were found to induce both @entity5567 and LTC4 synthesis. @entity5567 synthesis and LTC4 release were enhanced by preincubation of the basophils with @entity2772 or by elevation of cytosolic free @entity141 by @entity2426 . Incubation of @entity1 basophils with @entity2772 alone or @entity2426 alone did not result in detectable synthesis of @entity5567 and LTC4, whereas the combination of the two resulted in high amounts of @entity5567 and LTC4 synthesis. Depending on the stimulus used, LTC4 release was 5-100-fold higher than @entity5567 synthesis. In addition, @entity5567 , but not LTC4, was transiently detected, probably due to @entity5567 degradation. LTC4 and @entity5567 synthesis was strongly blocked by inhibitors of cytosolic phospholipase A2, indicating that this enzyme is involved in @entity5567 and LTC4 synthesis by activated @entity1 basophils. CONCLUSION: This study provides a first comprehensive comparison of @entity5567 and LTC4 synthesis in highly purified @entity1 basophils, stimulated with a variety of stimuli.
