title: Immunotherapy in a human ovarian cancer xenograft model with two bispecific monoclonal antibodies: OV-TL 3/CD3 and OC/TR.
abstract: The bispecific antibodies (bs-mAbs) OV-TL 3/CD3 and OC/TR (MOv18/CD3) efficiently mediate ovarian tumor cell lysis by cytotoxic T cells and activated peripheral blood lymphocytes (PBL) in vitro. OV-TL 3/CD3 and OC/TR are reactive with tumor-associated antigens on ovarian carcinoma cells (OA3 and CA-MOv18, respectively), and CD3 on activated PBL, bridging both cells and simultaneously inducing activation of the effector cells. In a comparative study we investigated the therapeutic efficacy of OV-TL 3/CD3 and OC/TR by targeting activated PBL with the bs-mAbs against intraperitoneally growing NIH:OVCAR-3 human ovarian carcinoma cells. As they have good tumor localization characteristics, HPLC-purified bispecific F(ab')2 fragments were used to target highly active PHA and IL-2-stimulated PBL effector cells. The efficacy of OV-TL 3/CD3 was compared to OC/TR with respect to tumor-associated antigen (TAA) binding on NIH:OVCAR-3 ascites cells and NIH:OVCAR-3 tumor cell lysis in vitro. In this report we show that ip ovarian cancer-bearing nude mice treated with IL-2 and activated PBL coated with bispecific F(ab')2 had a significantly longer survival than the untreated mice. No significant difference in survival was found between the OC/TR or OV-TL 3/CD3 bispecific antibody, although MOv18 expression was higher on NIH:OVCAR-3 ascites cells and PBL targeted with OC/TR induced slightly higher tumor cell lysis in vitro. Thus, the therapeutic efficacy of these bs-mAbs in vivo could not be predicted by TAA expression or bs-mAb-mediated tumor cell lysis in vitro.
authors.affiliation: Department of Pathology, University of Leiden, The Netherlands.
authors.forename: H H
authors.initials: HH
authors.lastname: van Ravenswaay Claasen
authors.forename: A M
authors.initials: AM
authors.lastname: Eggermont
authors.forename: Y A
authors.initials: YA
authors.lastname: Nooyen
authors.forename: S O
authors.initials: SO
authors.lastname: Warnaar
authors.forename: G J
authors.initials: GJ
authors.lastname: Fieuren
mesh_terms: D000818:Animals; D018033:Antibodies, Bispecific / Q000276:immunology / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal; D002277:Carcinoma / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D002455:Cell Division; D002469:Cell Separation; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D007167:Immunotherapy; D008214:Lymphocytes / Q000502:physiology; D051379:Mice; D008815:Mice, Inbred Strains; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010051:Ovarian Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D016019:Survival Analysis; D014183:Transplantation, Heterologous
chemical_list: D018033:Antibodies, Bispecific; D000911:Antibodies, Monoclonal