Investigation of murine spleen as a niche for hematopoiesis.
BACKGROUND
Spleen as a lymphoid tissue is specialized for monitoring blood and mounting immunity against blood-borne antigens. Antigen-presenting cells present in spleen commonly develop from bone marrow-derived precursors that enter blood circulation. However, a distinct splenic myeloid antigen-presenting cell subset described in this laboratory, namely "dendritic-like cells" (L-DC), has been hypothesized not to share a bone marrow origin.


METHODS
In this study, the presence of endogenous hematopoietic progenitors in spleen was investigated by transplanting intact spleen into allotype-distinct recipients and monitoring development of progeny cells in grafted tissues.


RESULTS
Successful engraftment of donor spleens was achieved for up to 4 weeks. After 2 weeks, donor-type myeloid cells, dendritic cells (DC) and few B cells were observed in spleen grafts indicative of spleen-endogenous hematopoiesis. An influx of host-type hematopoietic stem cell, as well as host-type lymphoid and myeloid cells, was also observed.


CONCLUSIONS
Evidence for the maintenance of donor-type myeloid cells after 2 to 4 weeks reflected development from hematopoietic progenitors endogenous to spleen. L-DC were also detected in spleen grafts; however, within the graft microenvironment they were one of the several DC and myeloid subsets, including activated DC, resembling L-DC. Overall, this study adds further evidence that spleen can support endogenous myelopoiesis.
Tan
Jonathan K H
JK
Research School of Biology, The Australian National University, Canberra, Australia.
O'Neill
Helen C
HC
D000818:Animals; D000831:Animals, Newborn; D001402:B-Lymphocytes / Q000276:immunology; D016026:Bone Marrow Transplantation / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology; D005434:Flow Cytometry; D006410:Hematopoiesis / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology; D007109:Immunity; D007519:Isoantigens / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D012079:Renal Circulation; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000276:immunology / Q000502:physiology* / Q000637:transplantation*; D013156:Splenectomy; D014184:Transplantation, Homologous / Q000276:immunology
D007519:Isoantigens