Detection of tryptase−, chymase cells in human CD34 bone marrow progenitors.

Shimizu, Y.; Suga, T.; Maeno, T.; Tsukagoshi, F.; Kawata, T.; Narita, T.; Takahashi, T.; Ishikawa, S.; Morishita, Y.; Nakajima, T.; Hara, F.; Miurati, T.; Kurabayashi, M.

Background: Mast cells (MCs) arise from haematopoietic stem cells. We have recently reported that CD34 progenitors derived from human bone marrow (BM) develop into tryptase , chymase MCs when cultured in the presence of recombinant human stem cell factor (rhSCF) and recombinant human IL-6 (rhIL-6). In an experiment for the expression of chymase during differentiation, chymase cells were detected in human BM, but tryptase cells were not found. Objective: The purpose of this study was to show the appearance of chymase cells in CD34 cells with an origin different from MC differentiation. Methods: CD34 cells from human BM were sorted with anti-CD117 monoclonal antibody (mAb), and cytospins of CD34 , CD34 CD117 , or CD34 CD117 were prepared. These cells were cultured with rhSCF rhIL-6 for 12 weeks. Some of the cells were subjected to either histological stain with Wright-Giemsa or immunocytochemistry with anti-chymase mAb. Real-time RT-PCR was also performed to compare the transcriptional level of chymase from each cell preparation. Results: Chymase was expressed in CD34 cells as well as human MCs by immunocytochemistry. Substantial CD34 CD117- cells, but not CD34 CD117 cells, were stained immunocytochemically with anti-chymase mAb. For 1 week culture with rhSCF rhIL-6, no cells expressed chymase in any preparation. Real-time RT-PCR revealed positivity for chymase mRNA in CD34 cells, but it reduced at 1 week of culture, and increased as cells developed into MCs. Chymase mRNA in CD34 CD117 cells was negligible compared with that in CD34 CD117-. Tryptase mRNA was below the detectable level in CD34 cells, and increased along with MC differentiation. After 12 weeks of culture, CD34 CD117 developed predominantly into MCs, whereas CD34 CD117- developed into monocytes/macrophages. Conclusion: Our findings suggested that chymase is present not only in MCs but also in CD34 CD117- BM progenitors, but that its origin is different from the MC lineage.

BONE marrow; MAST cells; ENZYMES; STEM cells; CELL differentiation; MONOCLONAL antibodies

Clinical & Experimental Allergy, 2004, Vol 34, Issue 11, p1719

0954-7894

Academic Journal

10.1111/j.1365-2222.2004.02105.x