Characterization of purification-associated reduction in IgE-dependent histamine release from rat peritoneal mast cells

Abstract

Histamine release from purified rat peritoneal mast cells (PMC) was examined and compared to that from a non-purified preparation (PEC). Both PEC and PMC released similar amounts of histamine upon stimulation with compound 48/80, calcium ionophore A23187 and substance P. In contrast, IgE-dependent histamine release from PMC caused by antigen, anti-IgE and concanavalin A was very low compared to that of PEC. The reduced IgE-dependent histamine release from PMC, however, was recovered when PMC was reconstituted with non-mast cells (NMC) present in the peritoneal cavity. The effect was time-dependent and reached a plateau in 30 min. NMC from both sensitized and non-sensitized rats recovered the reduced histamine release from PMC dose-dependently. The potentiating effect of NMC was observed even in the presence of excess amount of phosphatidylserine. Supernatants of NMC and a mixture of PMC and NMC incubated for 1 hr at 37 degrees C, however, failed to potentiate the histamine release. These results demonstrate that IgE-dependent histamine release from rat peritoneal mast cells is upregulated by other cells present in the peritoneal cavity, and that the mechanism involved is distinct from that of phosphatidylserine.

High Rate of IgE-Mediated Histamine Release from Rat Mesenteric Mast Cells.

“…Purification reduced the histamine release from peritoneal mast cells as reported previously [4,5]. These results indicate that mesenteric mast cells release higher rates of histamine than peritoneal mast cells.…”

“…A bellshaped dose-response curve was obtained, and over 50% of total histamine was released at an optimal antigen concentration, 10 µg/ml. The dose-response curve is almost comparable to that obtained with peritoneal mast cells reported previously [4,5]. Results of the kinetic study are shown in Fig.…”

“…Once purified, however, mast cells release only about 10% of total histamine. The reduced IgE-dependent histamine release from purified mast cells could be recovered by reconstitution with separated cells [4,5]. These results indicate that IgEdependent activation of mast cells is regulated by surrounding cells.…”

“…Next day, rats were sacrificed under ether anesthesia, and peritoneal cells were recovered. Histamine release from unpurified and purified preparations of peritoneal mast cells was examined as reported previously [4,5].…”

“…In contrast, peritoneal mast cells are floating single cells. In the peritoneal cavity, macrophages (about 90%), neutrophils and eosinophils are also present [5], and peritoneal mast cells may interact with these cells both directly and indirectly. Adhesion molecules on the peritoneal mast cell, however, seem to be inactive, because unstimulated peritoneal mast cells do not adhere to dishes coated with extracellular matrix proteins (unpublished data).…”