Deficient Eosinophil Chemotaxis-Promoting Activity of Genetically Normal Mast Cells Transplanted into Subcutaneous Tissue of Mitfmi-vga9/Mitfmi-vga9 Mice

摘要

Despite the practical lack of mast cells in the skin tissue of WBB6F1->Kit^>W>/Kit^>W-v, the skin tissue of WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice contains one third of mast cells than that of WBB6F1-+/+ mice. We attempted to investigate the function of the decreased but appreciable number of mast cells in the skin of WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice. The substance P (SP)-induced eosinophil infiltration was examined using air-bleb assay. The air-bleb membrane was composed of the subcutaneous connective tissue. Unexpectedly, we found that the air-bleb membranes formed in the back of WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice contained no mast cells. The WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice showed impaired SP-induced eosinophil infiltration as observed in WBB6F1->Kit^>W>/Kit^>W-v mice, indicating that mast cells detected in the dermis of WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice did not help SP-induced eosinophil infiltration. Subcutaneous transplantation of cultured mast cells from WBB6F1-+/+ mice normalized SP-induced eosinophil infiltration in WBB6F1->Kit^>W>/Kit^>W-v mice but not in WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice. The greater number and the more dispersed distribution pattern of mast cells that appeared in the subcutaneous connective tissue of WBB6F1->Kit^>W>/Kit^>W-v mice after the transplantation appeared to explain the difference between WBB6F1->Kit^>W>/Kit^>W-v and WBB6F1->Mitf^>mi-vga9>/Mitf^>mi-vga9 mice.