抄録
Immunoglobulin E (IgE)-dependent histamine release from purified rat peritoneal mast cells (PMC) is very low in comparison to that from a non-purified preparation (PEC). The reduced histamine release from PMC is recovered or potentiated by reconstitution with separated non-mast cells (NMC). In the present study, further characterization was undertaken to elucidate the mechanisms involved. Sensitized mast cells were recovered from peritoneal cavities of rats, and purified by density gradient centrifugation with Percoll. Effects of NMC reconstitution, membrane fraction of NMC, NMC incubation supernatant, adhesion molecules and extracellular matrix proteins on IgE-dependent histamine release from PMC were examined. IgE-dependent histamine release was significantly potentiated by NMC reconstitution to PMC. The potentiation was dependent on the concentration of NMC reconstituted and reached a plateau after 30 min incubation. Increasing concentration of PMC did not affect the histamine relase. Membrane fraction prepared from NMC also potentiated PMC histamine release in a dose-dependent manner. The potentiation reached a plateau in 5 min. Furthermore, incubation supernatant of NMC potentiated PMC histamine release. Antibodies against intercellular adhesion molecule (ICAM)-1, lymphocyte function-associated antigen (LFA)-1, very late activation antigen (VLA)-1, VLA-4 and VLA-6, and fibronectin did not affect the potentiation of PMC histamine release by NMC reconstitution. Fibronectin, laminin and collagen failed to potentiate PMC histamine release. These results indicate that the membrane component(s) of NMC in the rat peritoneal cavity seems to modulate IgE-dependent histamine release from peritoneal mast cells of rats, and that the active molecule(s) may be released from NMC. Adhesion molecules such as ICAM-1, LFA-1 and VLA are not involved.
