Pretreatment of rat peritoneal mast cells, human basophils, bone marrow-derived mouse mast cells (BMMC) and mouse mast cell line PT-18 cells with 1 μg/ml pertussis toxin (PT) failed to inhibit immunoglobulin E (IgE)-dependent histamine release from the cells. In BMMC and PT-18 cells, even 20-hr incubation of the cells with 1 μg/ml PT, which ADP-ribosylates more than 97% of 41 kDa, α-subunit of Ni in the cells, failed to affect the IgE-dependent release of histamine or arachidonate. The results indicate that GTP-binding protein, Ni, is not involved in the transduction of triggering signals induced by cross-linking of IgE receptors. In contrast, pretreatment of rat mast cells with 1 ng/ml to 0.1 μg/ml PT for 2 hr inhibited histamine release induced by compound 48/80 in a dose-dependent manner. A similar pretreatment with PT inhibited thrombin-induced histamine release from BMMC and N-formyl-L-methionyl-L-leucyl-L-phenylalanine-induced histamine release from human basophils in a similar dose-dependent fashion. However, even 20 hr of incubation of sensitized BMMC with 1 μg/ml PT failed to inhibit either thrombin-induced or antigen-induced breakdown of phosphatidylinositides (PI), i.e., the formation of inositol triphosphate and diacylglycerol, Quin-2 signal, and the release of arachidonic acid. The results indicate that the inhibition of thrombin-induced histamine release by PT-treatment is not due to the inhibition of PI-turnover, and that Ni is not involved in thrombin-induced or antigen-induced (IgE-dependent) hydrolysis of phosphatidylinositides in mast cells.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Immunology|
|State||Published - 1987|
ASJC Scopus subject areas
- Immunology and Allergy