Immunochemical relatedness between secretory phospholipase A2 and intracellular phospholipase A2 activity linked with arachidonic acid mobilization in macrophages.

To determine whether low mol. wt phospholipase A2 (PLA2) is involved in the mechanism of arachidonic acid mobilization induced by zymosan in mouse peritoneal macrophages, we developed an immunoblot analysis and ELISA assay using the polyclonal antibodies anti-PLA2 type I and type II previously characterized. We also measured the effect of low mol. wt PLA2 inhibitors such as p-bromophenacyl bromide, aristolochic acid, nordihydroguaiaretic acid, all trans-retinal and all trans-retinoic acid on the action of these enzymes. The antibodies antitype I PLA2 bound to mouse platelet protein fraction, while the antibodies antitype I or antitype II did not recognize components of the macrophages. Furthermore, low mol. wt PLA2 inhibitors did not inhibit arachidonic acid release produced during the phagocytosis of zymosan. This suggests that low mol. wt PLA2 are not present in cells such as macrophages. These results are consistent with a role for high mol. wt PLA2 in arachidonic acid mobilization.