Methods for Manipulating Phagocytosis Mediated by CD47
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsSiddhartha Jaiswal, Irving L. Weissman, Ravindra Majeti, Mark P. Chao
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Abstract
Methods are provided to manipulate phagocytosis of cells, including hematopoietic cells, e.g. circulating hematopoietic cells, bone marrow cells, acute leukemia cells, etc.; and solid tumor cells. In some embodiments of the invention the circulating cells are hematopoietic stem cells, or hematopoietic progenitor cells, particularly in a transplantation context, where protection from phagocytosis is desirable. In other embodiments the circulating cells are leukemia cells, particularly acute myeloid leukemia (AML), where increased phagocytosis is desirable.
Claims13
1-10. (canceled)
A method of determining increased CD47 expression on human AML LSC as compared to human HSC cells comprising:
- obtaining HSC from samples of normal human mobilized peripheral blood;
- obtaining AML LSC from samples of human AML cells;
- determining the relative expression of CD47 on the surface of the HSC cells and the AML LSC cells by flow cytometry using a fluorescent-labeled anti-CD47 antibody.
A method of measuring an increase in phagocytosis of AML LSC cells by an anti-CD47 monoclonal antibody in vitro comprising:
- obtaining primary human AML LSC from samples of AML;
- purifying the AML LSC by FACS and loading the cells with a fluorescent dye;
- incubating the purified, labeled AML LSC with mouse bone-marrow derived macrophage in the presence or absence of a mouse anti-human CD47 monoclonal antibody that disrupts the interaction between CD47 and SIRPalpha;
- monitoring the AML LSC cells with immunofluorescence microscopy or flow cytometry to identify phagocytosed cells;
- and
- comparing the amount of phagocytosis of the AML LSC cells in the presence and absence of the anti-CD47 antibody.
An animal model for expression of CD47 on human leukemic cells, comprising:
- a mouse transplanted with human acute myeloid leukemia (AML) cells transduced with a Tet-CD47 lentivirus.
Dependencies are inferred from the claim text.