title: Delivery of NKG2D ligand using an anti-HER2 antibody-NKG2D ligand fusion protein results in an enhanced innate and adaptive antitumor response.
abstract: NKG2D ligands link the innate and adapative immune response by activating the receptors expressed on effector cells of both the innate (NK) and adaptive immune systems (CD8(+) T cells). In this study, we explored the potential therapeutic utility of this intersection by fusing the murine NKG2D ligand Rae-1β to the 3' end of an anti-HER2 IgG3 antibody containing an intact Fc domain (anti-HER2 IgG3-Rae-1β), thereby targeting an NK cell activation signal to HER2+ breast tumor cells. The antitumor efficacy of this anti-HER2-Rae-1β fusion protein was examined in a mouse mammary tumor model engineered to express HER2 (EMT6-HER2 cells). We observed an enhanced cytotoxic response of NK effectors against EMT-HER2 cells in vitro. Mice implanted on one flank with EMT6-HER2 cells and contralaterally with control EMT6 cells exhibited rapid regression of EMT6-HER2 tumors but delayed regression of contralateral EMT6 tumors. IFNγ was implicated, given a lack of antitumor efficacy in IFNγ(-/-) mice. Depletion of either NK cells or CD8(+) T cells abrogated tumor growth inhibition, suggesting essential roles for each in the observed antitumor activity. Mice rejecting EMT6-HER2 tumors after anti-HER2-Rae-1β treatment showed markedly decreased tumor growth when rechallenged with EMT6-HER2 or EMT6 cells, whereas both EMT6 and EMT6-HER2 cells grew in control mice, indicating the development of an adaptive memory response. Our findings demonstrate that administration of an antibody-NKG2D ligand fusion protein can enhance innate and adaptive immune antitumor responses, also evoking additional nontargeted antigens to enhance the potential clinical utility of this approach.
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, University of Miami Miller School of Medicine and Sylvester Comprehensive Cancer Center, Miami, Florida 33136, USA.
authors.forename: Hyun-Mi
authors.initials: HM
authors.lastname: Cho
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Rosenblatt
authors.forename: Khaled
authors.initials: K
authors.lastname: Tolba
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Shin
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Shin
authors.forename: Carmen
authors.initials: C
authors.lastname: Calfa
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Seung-Uon
authors.initials: SU
authors.lastname: Shin
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D001943:Breast Neoplasms / Q000276:immunology* / Q000628:therapy*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007074:Immunoglobulin G / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D008325:Mammary Neoplasms, Experimental / Q000276:immunology* / Q000628:therapy*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000235:genetics / Q000276:immunology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology
chemical_list: D007074:Immunoglobulin G; D008565:Membrane Proteins; D055655:NK Cell Lectin-Like Receptor Subfamily K; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C491218:Raet1b protein, mouse