title: Mono- and dual-targeting triplebodies activate natural killer cells and have anti-tumor activityin vitroandin vivoagainst chronic lymphocytic leukemia.
abstract: Chronic lymphocytic leukemia (CLL) is the most common form of leukemia that affects B lymphocytes in adults. Natural killer (NK) cells in CLL patients are intrinsically potent but display poorin situeffector functions. NKG2D is an activating receptor found on NK and CD8+T cells and plays a role in immunosurveillance of CLL. In this study, we developed mono- and dual-targeting triplebodies utilizing a natural ligand for human NKG2D receptor (ULBP2) to retarget NK cells against tumor cells. Triplebodies in both formats showed better ability to induce NK-cell-dependent killing of target cells compared to bispecific counterparts. A mono-targeting triplebody ULBP2-aCD19-aCD19 successfully triggered NK cell effector functions against CLL cell line MEC1 and primary tumor cells in allogenic and autologous settings. Additionally, a dual-targeting triplebody ULBP2-aCD19-aCD33 specific for two distinct tumor-associated antigens was developed to target antigen loss variants, such as mixed lineage leukemia (MLL). Of note, this triplebody exhibited cytotoxic activity against CD19/CD33 double positive cells and retained its binding features even in the absence of one of the tumor antigens. Further, ULBP2-aCD19-aCD19 showed significantin vivoactivity in immune-deficient (NSG) mouse model transplanted with CLL cell line as target cells and human immune cells as an effector population providing a proof-of-principle for this therapeutic concept.
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Maulik
authors.initials: M
authors.lastname: Vyas
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Ann-Charlott
authors.initials: AC
authors.lastname: Schneider
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Shatnyeva
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Katrin S
authors.initials: KS
authors.lastname: Reiners
authors.affiliation: Department of Experimental Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Samir
authors.initials: S
authors.lastname: Tawadros
authors.affiliation: Institute of Cellular Therapeutics, IFB-Tx, Hannover Medical School , Hannover, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Kloess
authors.affiliation: Institute of Cellular Therapeutics, IFB-Tx, Hannover Medical School , Hannover, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Köhl
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hallek
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne , Cologne, Germany.
authors.forename: Hinrich P
authors.initials: HP
authors.lastname: Hansen
authors.affiliation: Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany; Experimental Tumor Research, Center for Tumor Biology and Immunology, Philipps University Marburg, Marburg, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Pogge von Strandmann
keywords: CD19; CLL; NK cells; NKG2D; ULBP2; immunoligand; triplebody