title: Mutated SEA-D227A-conjugated antibodies greatly enhance antitumor activity against MUC1-expressing bile duct carcinoma.
abstract: For the purpose of establishing a new adoptive immunotherapy for bile duct carcinoma (BDC), we have directed our attention to superantigens (SAgs), the most potent known activators of T lymphocytes. In our previous study, staphylococcal enterotoxin A (SEA) was conjugated chemically with MUSE11 mAb, which recognizes the MUC1 cancer-associated antigen, and shown to enhance the specific cytotoxic activity of T-LAK cells against MUC1-expressing BDC cells (TFK-1) in vitro and in vivo. However, it is probable that SEA might cause side-effects because of nonspecific binding to class II positive cells. In order to overcome these, we generated mutated SEA (mSEA) by changing Asp at position 227 of native SEA to Ala, which has reduced affinity to MHC class II molecules, but retains the potential for T cell activation. When mSEA-D227A was administered to rabbits to examine effects on blood pressure, 500 times more mSEA-D227A was tolerated than native SEA. This prompted us to construct a mSEA-D227A-conjugated mAb, reactive with MUC1. It augmented the antitumor activity of T-LAK cells significantly, and furthermore, mSEA-D227A could be conjugated to two bispecific antibodies, BsAb (anti-MUC1 x anti-CD3) and BsAb (anti-MUC1 x anti-CD28), which in combination had greater enhancing effects than mSEA-D227A-conjugated anti-MUC1 mAb, and combination of unconjugated BsAbs. These findings indicate a utility of mSEA-D227A-conjugated antibodies for targeted cancer immunotherapy.
authors.affiliation: First Department of Surgery, Tohoku University School of Medicine, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kodama
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Katayose
authors.forename: M
authors.initials: M
authors.lastname: Shinoda
authors.forename: N
authors.initials: N
authors.lastname: Sakurai
authors.forename: S
authors.initials: S
authors.lastname: Takemura
authors.forename: H
authors.initials: H
authors.lastname: Yoshida
authors.forename: H
authors.initials: H
authors.lastname: Saeki
authors.forename: M
authors.initials: M
authors.lastname: Ichiyama
authors.forename: K
authors.initials: K
authors.lastname: Tsumoto
authors.forename: R
authors.initials: R
authors.lastname: Asano
authors.forename: I
authors.initials: I
authors.lastname: Kumagai
authors.forename: K
authors.initials: K
authors.lastname: Imai
authors.forename: Y
authors.initials: Y
authors.lastname: Hinoda
authors.forename: S
authors.initials: S
authors.lastname: Matsuno
authors.forename: T
authors.initials: T
authors.lastname: Kudo
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000627:therapeutic use; D001650:Bile Duct Neoplasms / Q000276:immunology* / Q000628:therapy; D003602:Cytotoxicity, Immunologic; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology*; D005260:Female; D006801:Humans; D016219:Immunotherapy, Adoptive; D051379:Mice; D016513:Mice, SCID; D018396:Mucin-1 / Q000276:immunology*; D009368:Neoplasm Transplantation; D018089:Superantigens / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D004768:Enterotoxins; D018396:Mucin-1; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal