OBJECTIVETo explore the hematopoietic stem cell distribution and lymphocyte proliferation and differentiation in recipient mice after allogeneic bone marrow transplantation (allo-BMT).

METHODSBALB/c (H-2(d)) mice were total body irradiated 5.5 Gy x 2 by (137)Cs and then transplanted with bone marrow cells from GFP transgenic C57BL/6J (H-2(b)) mice. The femur, spleen, Peyer patches, thymus, liver and peripheral blood of the host were collected on days 3, 7, 21, 35 and 70 post transplantation, and their sections were observed by fluorescent microscopy. The green fluorescent cells were counted with FACS. The phycoerythrin (PE) labeled antibodies to CD4, CD8 and B220 were used for sorting T and B lymphocytes.

RESULTS(1) On day 3 and day 7 after allo-BMT, there were (1.06 +/- 0.02)% and (76.60 +/- 1.80)% of donor's green bone marrow cells in host's spleen respectively, whereas only (0.37 +/- 0.06)% and (39.70 +/- 5.38)% in the bone marrow, respectively. (2) In bone marrow and other organs of 21 day-old chimerism mice, over 60% cells were of donor origin. (3) There were (0.36 +/- 0.04)% donor's bone marrow cells lodging at host's Peyer patches, similar to that in bone marrow.

CONCLUSION(1) The engrafted allogeneic hematopoietic stem cell can move into spleen, bone marrow, Peyer patches and thymus. The spleen is the main lodging place of the engrafted cells early after all-BMT. (2) The majority of cells in chimerism mice immunologic organs were of donor origin. (3) Peyer patches is another lodging place early after allo-BMT.