Growth of Human Hematopoietic Cells in Immunodeficient Mice Conditioned with Cyclophosphamide and Busulfan

Abstract

Human hematopoietic cells survive and proliferate for at least 10 weeks in severe combined immunodeficient mice prepared with the cytotoxic drugs busulfan and cyclophosphamide. The human cells growing in the mice can be detected by in situ hybridization using a probe detecting human repetitive DNA or by staining the cells with antihuman antibodies (anti-CD45 and anti-HLA I). Busulfan/cyclophosphamide-treated mice were injected with a wide range of cell doses, ranging from 5 to 50 million unfractionated bone marrow cells and 2 to 40 million low density bone marrow cells. Animals were killed at 1, 3, 5, 7 and 10 weeks after transplantation. Human cells were found in many animals and could be detected as early as one week after transplantation. The peak of repopulation was at two to five weeks, but in some animals human cells could be detected for as long as 10 weeks. Many of the human cells expressed high levels of glycophorin, but mature human erythrocytes were not found.The human cells were not uniformly distributed throughout the marrow. They grew in small clusters in the subepiphyseal region. The extent of human hematopoietic repopulation in the mouse was extremely variable. At no time and at no dose was repopulation achieved in all of the animals. Treatment with human growth factors is not necessary for the survival of the human hematopoietic cells but, in their absence, normal hematopoiesis does not occur.

Costimulation Blockade, Busulfan, and Bone Marrow Promote Titratable Macrochimerism, Induce Transplantation Tolerance, and Correct Genetic Hemoglobinopathies with Minimal Myelosuppression

“…Busulfan is an alkylating agent that produces preferential depletion of early hemopoietic stem cells (HSCs) (11)(12). It is commonly used in a multidose fashion and always in conjunction with other chemotherapeutic agents for recipient conditioning in many clinical BM transplant regimens (13).…”

Combinations of Anti-LFA-1, Everolimus, Anti-CD40 Ligand, and Allogeneic Bone Marrow Induce Central Transplantation Tolerance through Hemopoietic Chimerism, Including Protection from Chronic Heart Allograft Rejection

“…In this report, we show that combinations of anti-LFA-1 with anti-CD40L or the rapamycin derivative everolimus (40-O-(2-hydroxyethyl)-rapamycin) (23) induce stable, mixed hemopoietic chimerism upon transfer of a single standard dose of allogeneic BM cells (2 ϫ 10 7 ), and irradiation-free conditioning with the alkylating agent busulfan for partial depletion of early hemopoietic stem cells (13,24). While combined treatment with anti-LFA-1 and anti-CD40L resulted in high incidences of stable chimerism, with comparable efficacy to anti-CD40L and everolimus, about one-half of the BM recipients treated with anti-LFA-1 and everolimus eventually lost chimerism.…”

SCID mice model in vivo evaluation of autologous and allogeneic dendritic cells activity on B-cell chronic lymphocytic leukemia.

“…Before the implantation of human cells the animals were immunosupressed by s.c. injection of cyclofosfamide, 3mg/animal on the day 3 and the day 2 before inoculation of the human cells [20,21]. Then the animals were treated every 2-3 days s.c. with hybridoma PK136 cells culture supernatant containing the anti-NK1.1 monoclonal antibodies (4 μg IgG) to suppress mice NK cells activity [22].…”