title: Bispecific antibodies targeting tumor-associated antigens and neutralizing complement regulators increase the efficacy of antibody-based immunotherapy in mice.
abstract: The efficacy of antibody-based immunotherapy is due to the activation of apoptosis, the engagement of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity (CDC). We developed a novel strategy to enhance CDC using bispecific antibodies (bsAbs) that neutralize the C-regulators CD55 and CD59 to enhance C-mediated functions. Two bsAbs (MB20/55 and MB20/59) were designed to recognize CD20 on one side. The other side neutralizes CD55 or CD59. Analysis of CDC revealed that bsAbs could kill 4-25 times more cells than anti-CD20 recombinant antibody in cell lines or cells isolated from patients with chronic lymphocytic leukemia. The pharmacokinetics of the bsAbs was evaluated in a human-SCID model of Burkitt lymphoma. The distribution profile of bsAbs mimics the data obtained by studying the pharmacokinetics of anti-CD20 antibodies, showing a peak in the tumor mass 3-4 days after injection. The treatment with bsAbs completely prevented the development of human/SCID lymphoma. The tumor growth was blocked by the activation of the C cascade and by the recruitment of macrophages, polymorphonuclear and natural killer cells. This strategy can easily be applied to the other anti-tumor C-fixing antibodies currently used in the clinic or tested in preclinical studies using the same vector with the appropriate modifications.
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Macor
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Secco
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: N
authors.initials: N
authors.lastname: Mezzaroba
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Zorzet
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Durigutto
authors.affiliation: National Institute for Biological Standards and Control (NIBSC), Hertfordshire, UK.
authors.forename: T
authors.initials: T
authors.lastname: Gaiotto
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: L
authors.initials: L
authors.lastname: De Maso
authors.affiliation: Institute for Maternal and Child Health-IRCCS 'Burlo Garofolo', Trieste, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Biffi
authors.affiliation: Institute for Maternal and Child Health-IRCCS 'Burlo Garofolo', Trieste, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Garrovo
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Capolla
authors.affiliation: Department of Human Pathology, University of Palermo, Palermo, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Tripodo
authors.affiliation: Clinical and Experimental Onco-Hematology Unit, Centro di Riferimento Oncologico, I.R.C.C.S., Aviano, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Gattei
authors.affiliation: Department of Life Sciences, University of Trieste, Trieste, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Marzari
authors.affiliation: IRCCS Istituto Auxologico Italiano, Milan, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Tedesco
authors.affiliation: Department of Health Sciences and IRCAD, University of Eastern Piedmont, Novara, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Sblattero
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D018033:Antibodies, Bispecific / Q000737:chemistry*; D000920:Antibody-Dependent Cell Cytotoxicity / Q000276:immunology; D018951:Antigens, CD20 / Q000737:chemistry; D002051:Burkitt Lymphoma / Q000276:immunology*; D018958:CD55 Antigens / Q000737:chemistry; D018957:CD59 Antigens / Q000737:chemistry; D002469:Cell Separation; D003001:Cloning, Molecular; D003165:Complement System Proteins; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D007694:Killer Cells, Natural / Q000166:cytology; D008264:Macrophages / Q000166:cytology; D051379:Mice; D016513:Mice, SCID; D008856:Microscopy, Fluorescence
chemical_list: D000906:Antibodies; D018033:Antibodies, Bispecific; D018951:Antigens, CD20; D018958:CD55 Antigens; D018957:CD59 Antigens; D003165:Complement System Proteins