Evidence for migration of donor bone marrow stromal cells into recipient thymus after bone marrow transplantation plus bone grafts: A role of stromal cells in positive selection.
Intrathymic T-cell differentiation is characterized by two selection events: positive and negative selection. It has been shown that thymic epithelial cells in the cortex are involved in the positive selection, while macrophages and dendritic cells, derived from hemopoietic stem cells, are involved in the negative selection. Here we investigate whether donor-derived bone marrow stromal cells can migrate into the thymus and participate there in positive selection after bone marrow transplantation plus bone grafts (to recruit bone marrow stromal cells). Allogeneic bone marrow transplantation with or without bone grafts was carried out in the [C57BL/6-->C3H] combination. Fluorescence-activated cell sorter analyses of recipient thymic adherent cells showed that donor-type bone marrow stromal cells exist in the thymus of mice that received bone marrow plus bone grafts but not in the mice that received bone marrow cells alone. Histological examination using confocal microscopy also confirmed the existence of donor-type stromal cells in the thymus of mice that received bone marrow cells plus bones. Both T-cell proliferation and plaque-forming cell assays indicated that the T cells of such mice show donor-type major histocompatibility complex-restriction. These findings strongly suggest that stromal cells can migrate from the bone marrow to the thymus, where they participate in the positive selection of thymocytes.
Li
Y
Y
First Department of Pathology, Kansai Medical University, Osaka, Japan.
Hisha
H
H
Inaba
M
M
Lian
Z
Z
Yu
C
C
Kawamura
M
M
Yamamoto
Y
Y
Nishio
N
N
Toki
J
J
Fan
H
H
Ikehara
S
S
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D000941:Antigens / Q000276:immunology; D001854:Bone Marrow Cells / Q000166:cytology*; D016026:Bone Marrow Transplantation; D016025:Bone Transplantation; D002448:Cell Adhesion; D002465:Cell Movement; D006183:H-2 Antigens / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D017154:Stromal Cells / Q000166:cytology* / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology*; D014019:Tissue Donors
D000941:Antigens; D006183:H-2 Antigens