Human Hematopoietic Stem Cell (HSC)-Engrafted NSG Mice for HIV Latency Research

AbstractThe nonobese diabetic/severe combined immune deficiency (NOD-scid) xenotransplantation model is the “gold standard” for assaying human hematopoietic stem cell activity. Systematic advancements, such as depletion of natural killer cell activity with anti-CD122 antibody, direct intrafemoral injection, and deletion or truncation of IL2Rγ, have improved human cell engraftment; however, questions remain whether these mouse models are equivalent or, if not, which model is superior for assaying hematopoietic stem cell activity. To address this, we compared overall engraftment and multilineage differentiation of near-limiting doses of lineage-depleted human umbilical cord blood cells by direct intrafemoral injection into NOD/Lt-scid, NOD/Shi-scid, NOD/Lt-scid/IL2Rγnull (NSG), and NOD/Shi-scid/IL2Rγnull mice. Transplantation into NSG mice generated moderately higher human engraftment levels in bone marrow compared with other strains. At limiting doses, NSG mice of both sexes were 3.6-fold more sensitive in detecting SCID-repopulating cells compared with NOD/Lt-scid mice. However, NSG females exhibited higher engraftment at limiting cell doses, resulting in an overall increase in SCID-repopulating cell detection of 9-fold. Both NSG and NOD/Shi-scid/IL2Rγnull support significantly improved engraftment in peripheral tissues compared with NOD/Lt-scid and NOD/Shi-scid mice, whereas NSG mice provide greater human engraftment in bone marrow than all other strains, especially at limiting doses.

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Combining Mobilizing Agents with Busulfan to Reduce Chemotherapy-Based Conditioning for Hematopoietic Stem Cell Transplantation

Cells ◽

10.3390/cells10051077 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1077

Author(s):

Laura Garcia-Perez ◽

Lieke van van Roon ◽

Marco W. Schilham ◽

Arjan C. Lankester ◽

Karin Pike-Overzet ◽

...

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

Hematopoietic Stem Cell ◽

Dependent Manner ◽

Clinical Use ◽

Immune Recovery ◽

Direct Effects ◽

Hematopoietic Stem ◽

Nsg Mice ◽

Conditioning Regimens

In the context of hematopoietic stem cell (HSC) transplantation, conditioning with myelo- and immune-ablative agents is used to eradicate the patient’s diseased cells, generate space in the marrow and suppress immune reactions prior to the infusion of donor HSCs. While conditioning is required for effective and long-lasting HSC engraftment, currently used regimens are also associated with short and long-term side effects on extramedullary tissues and even mortality. Particularly in patients with severe combined immunodeficiency (SCID), who are generally less than 1-year old at the time of transplantation and often suffer from existing comorbidities. There is a pressing need for development of alternative, less toxic conditioning regimens. Hence, we here aimed to improve efficacy of currently used myeloablative protocols by combining busulfan with stem-cell niche-directed therapeutic agents (G-CSF or plerixafor) that are approved for clinical use in stem cell mobilization. T, B and myeloid cell recovery was analyzed in humanized NSG mice after different conditioning regimens. Increasing levels of human leukocyte chimerism were observed in a busulfan dose-dependent manner, showing comparable immune recovery as with total body irradiation in CD34-transplanted NSG mice. Notably, a better T cell reconstitution compared to TBI was observed after busulfan conditioning not only in NSG mice but also in SCID mouse models. Direct effects of reducing the stem cell compartment in the bone marrow were observed after G-CSF and plerixafor administration, as well as in combination with low doses of busulfan. Unfortunately, these direct effects on the stem population in the bone marrow were not reflected in increased human chimerism or immune recovery after CD34 transplantation in NSG mice. These results indicate moderate potential of reduced conditioning regimens for clinical use relevant for all allogeneic transplants.

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