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Updated: Feb 23, 2026
Isolation of Peritoneum-derived Mast Cells and Their Functional Characterization with Ca2+-imaging and Degranulation Assays
Published on: July 4, 2018
Simultaneous induction of HSP70 expression, and degranulation, in IgE/Ag-stimulated or extracellular HSP70-stimulated
X Li1, S Kanegasaki2,3, F Jin1
1College of Pharmacy, Yeungnam University, Gyeongsan, Korea.
Background:
In mast cells, induction of HSP70 expression during antigen stimulation has not been reported.
Methods:
Mouse bone marrow-derived mast cells (BMMC) were stimulated with IgE/Ag or HSP70. Induction of HSP70 expression and signaling protein phosphorylation were evaluated by immunoblotting.
Results:
HSP70 expression is induced in BMMC at an early stage of IgE/Ag-dependent stimulation, some of which is released from the cells in a granule-associated form. Induction of HSP70 expression was also observed with an IgE/Ag-stimulated human basophilic cell line, indicating that the phenomenon is not restricted to mouse BMMC. The induction of HSP70 expression, and its release, followed a similar time course to that of degranulation. Released HSP70 seems to be responsible for degranulation and production of eicosanoids, at least in part, because a neutralizing anti-HSP70 antibody mitigated these activities and because exogenous HSP70 not only induced immediate degranulation followed by autocrine HSP70 expression but also enhanced degranulation in IgE/Ag-stimulated BMMC. Extracellular HSP70 was found to induce phosphorylation of linker for activation of T cells (LAT) and a series of downstream signaling molecules in BMMC. We further found that Fyn, Lyn, and spleen tyrosine kinase (Syk), which are known to concern LAT phosphorylation in IgE/Ag-stimulated BMMC, were not phosphorylated in HSP70-stimulated BMMC, whereas lymphocyte-specific protein tyrosine kinase (Lck) was phosphorylated.
Conclusion:
FcεRI stimulation in BMMC and basophils induces HSP70 expression and its release. Extracellular HSP70 induces degranulation and mediator release via phosphorylation of LAT.
