Isolation and characterization of canine hematopoietic progenitor cells

Objective, The purpose of this study was to purify and characterize canine hematopoietic progenitor cells for surface antigen phenotype and reconstitu tion ability, Methods. Canine hematopoietic progenitor cells were isolated by density gra dient sedimentation, lineage depletion with monoclonal antibodies, and fluo rescence-activated cell sorting (FACS) for selection of cells with low-forw ard and right-angle scatter that were rhodamine 123 (Rh-123)(dull). Isolate d cells were characterized for expression of CD34, c-kit, and Flt-3, A cani ne/murine xenograft model and a mixed-chimerism assay were used to examine the in vivo proliferative potential of isolated cells. Results. The lineage-positive (Lin(+)) cells represented 80 +/- 11% (n = 22 ) of the input mononuclear cells, Lineage depletion resulted in a fourfold increase in colony-forming unit granulocyte/monocyte (CFU-GM), a 2.5-fold i ncrease in burst-forming unit-erythroid (BFU-E), and a twofold increase in the number of Rh-123(dull) cells over nonlineage-depleted bone marrow monon uclear cells (BMMCs). Lineage depletion led to a 2.7-fold enrichment of CD3 4 cells, a 10.4-fold enrichment of c-kit cells, and a 10.8-fold enrichment of CD34/c-kit(++) cells over total BMMCs, Nineteen percent of lineage-negat ive (Lin) cells were positive for Flt-3, Injection of canine cells into irr adiated (400 rads) NOD/SCID mice resulted in the detection of canine CD45() cells with BMMCs, Lin- cells, or Rh-123(dull) cells, Transplantation of p urified Lin- cells in dog leukocyte antigen-matched littermates resulted in low-level engraftment for at least In weeks. Conclusion. The development of methods for purification and characterizatio n of canine hematopoietic progenitor cells should enhance the utilization o f the canine model for a variety of experimental and therapeutic purposes. (C) 2001 International Society for Experimental Hematology Published by Els evier Science Inc.