title: Targeting of Lin-Sca+ hematopoietic stem cells with bispecific antibodies to injured myocardium.
abstract: Bispecific antibodies (BiAbs) are being used to target T cells or other immune cells to antigen-specific tumor targets. Anti-CD3 activated T cells (ATC) armed with anti-CD3 x anti-HER2 BiAb (HER2Bi) have been used to target Her2/neu + breast and prostate carcinoma cells. We adapted BiAb technology to target stem cells to injured myocardium. Since myocardial infarctions can lead to cardiac death and disability, rapid repair and rejuvenation of damaged myocardium is critically needed. Effective homing of stem cells and transdifferentiation of the stem cells into functional elements of the myocardium is needed for repair of damaged myocardium. We use a BiAb that binds c-kit on murine stem cells and VCAM-1 adhesion molecules up-regulated on injured myocardial cells. To test for specific binding and homing in a mouse, we produced anti-c-kit x anti-VCAM-1 to target purified Lin-Sca+ murine stem cells to the injured myocardium. Mice with infarcts created by ligation of the left anterior descending artery (LAD) were directly injected with armed stem cells or injected via the internal jugular vein (IJ) with FACS sorted Lin-Sca+ stem cells from bone marrow after fluorescent dye labeling. There were increased numbers of armed Lin-Sca+ cells retained in infracted myocardium after direct injection of armed Lin-Sca+ cells and increased numbers of Lin-Sca+ cells that were found in injured myocardium after IJ injection. These results suggest that stem cells retargeted with BiAb can be directly injected and retained by injured myocardium or targeted to injured myocardial tissues for tissue regeneration.
authors.affiliation: Immunotherapy Program, Adele R. Decof Cancer Center, Providence, RI 02908, USA. llum@rwmc.org
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Lum
authors.forename: Hubert
authors.initials: H
authors.lastname: Fok
authors.forename: Richard
authors.initials: R
authors.lastname: Sievers
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Abedi
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Quesenberry
authors.forename: Randall J
authors.initials: RJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D018033:Antibodies, Bispecific / Q000494:pharmacology / Q000627:therapeutic use*; D000943:Antigens, Differentiation / Q000276:immunology*; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology*; D051379:Mice; D009203:Myocardial Infarction / Q000628:therapy*; D009206:Myocardium / Q000737:chemistry / Q000473:pathology; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis / Q000276:immunology; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis / Q000276:immunology
chemical_list: D018033:Antibodies, Bispecific; D000943:Antigens, Differentiation; D019010:Vascular Cell Adhesion Molecule-1; C047076:senescent cell differentiation antigen; D019009:Proto-Oncogene Proteins c-kit