title: Preparation and in-vitro bioactivity of a novel superantigen conjugate targeting bladder carcinoma.
abstract: OBJECTIVE
  Superantigens have shown potent effects against bladder tumours by inducing Vbeta-specific T-lymphocyte proliferation and massive cytokine release but therapeutic benefit is compromised by cytotoxicity towards non-malignant cells and hypotoxicity to major histocompability complex (MHC) II-negative tumour cells. We are therefore interested in a conjugate preparation of a monoclonal antibody (MAb)-superantigens conjugate for which these drawbacks would be resolved.
  
  
  METHODS
  The Fab fragment of the anti-bladder carcinoma MAb BDI-1 was conjugated to one member of the staphylococcal enterotoxin A (SEA) superantigen using the chemical conjugating reagent, N-succinimidyl 3-(2-pyridyldithio) propionate.
  
  
  RESULTS
  After HPLC purification through a Superdex-200 gel column, another peak with a molecular mass of 250 KDa was observed before Fab and SEA were eluted. Indirect immunocytochemical analysis and immunofluorescence tests showed that the cell membranes of most human bladder cancer cells were positively stained only by the conjugate, confirming the ability of the conjugate to target human bladder carcinoma. Peripheral blood mononuclear cell proliferation and cytokine release were similar with the conjugate and SEA. Cytotoxicity targeting in MHC II-negative bladder cancer cell lines, evaluated by flow cytometry, showed significant differences between the conjugate and SEA, whereas there was no difference in the Lovo colon cancer cell line.
  
  
  CONCLUSIONS
  These findings indicate the conjugate of SEA protein and BDI-1 Fab fragment was prepared successfully and targeted bladder carcinoma in vitro.
authors: School of Clinical Medicine, Southeast University, Nanjing, PR China.
authors: Gong
authors: G
authors: Zhen
authors: Han
authors: H
authors: Cong-hui
authors: Hao
authors: H
authors: Lin
authors: Yang
authors: Y
authors: Jian-jun
authors: Tang
authors: T
authors: Wen-hao
authors: Teng
authors: T
authors: Gao-jun
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D004768:Enterotoxins / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018089:Superantigens / Q000737:chemistry* / Q000276:immunology / Q000494:pharmacology; D001749:Urinary Bladder Neoplasms / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D016207:Cytokines; D004768:Enterotoxins; D000949:Histocompatibility Antigens Class II; D007140:Immunoglobulin Fab Fragments; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal