title: Reduction of human melanoma tumor growth in severe combined immunodeficient mice by passive transfer of antibodies induced by a high molecular weight melanoma-associated antigen mimotope vaccine.
abstract: OBJECTIVE
  The high molecular weight melanoma-associated antigen (HMW-MAA) is an attractive target for immunotherapy of malignant melanoma. We have recently generated a vaccine based on the HMW-MAA mimotope 225D9.2+ that was able to induce anti-HMW-MAA antibodies with antitumor activity in vitro. Here, we investigated the antitumor activity of these antibodies in a human melanoma xenotransplant severe combined immunodeficient (SCID) mouse model.
  
  
  METHODS
  Tumors were established by injecting the human melanoma 518A2 cells into C.B.17 SCID/SCID mice. In tumor prevention experiments, 200 microg purified total IgG antibodies were injected intravenously the same day or on day 5 in therapeutic experiments. Antibody administration was repeated every fourth day and tumor volumes were measured. Antibody specificity and tumor infiltration by macrophages were investigated by immunohistochemistry.
  
  
  RESULTS
  Within 35 days after cell inoculation, antibody treatment reduced tumor growth up to 40% in the therapeutic and up to 62% in the tumor prevention experiments compared with the control mice. In tumors of all groups, a similar distribution of the HMW-MAA and no differences in infiltration of macrophages were detected by immunohistochemistry.
  
  
  CONCLUSIONS
  Here, we showed that antibodies induced by the 225D9.2+ mimotope effectively inhibited melanoma tumor growth. Additional mechanisms besides antibody-dependent cell cytotoxicity like disruption of interactions of melanoma cells mediated by extracellular matrix components seem to be involved in tumor growth inhibition. Based on our findings, we suggest that active immunization with this mimotope might be a promising strategy for treatment of melanoma.
authors.affiliation: Department of Pathophysiology, Center for Physiology and Pathophysiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wagner
authors.forename: Clemens
authors.initials: C
authors.lastname: Krepler
authors.forename: Dorothee
authors.initials: D
authors.lastname: Allwardt
authors.forename: Julia
authors.initials: J
authors.lastname: Latzka
authors.forename: Sabine
authors.initials: S
authors.lastname: Strommer
authors.forename: Otto
authors.initials: O
authors.lastname: Scheiner
authors.forename: Hubert
authors.initials: H
authors.lastname: Pehamberger
authors.forename: Ursula
authors.initials: U
authors.lastname: Wiedermann
authors.forename: Christine
authors.initials: C
authors.lastname: Hafner
authors.forename: Heimo
authors.initials: H
authors.lastname: Breiteneder
mesh_terms: D000818:Animals; D000912:Antibodies, Neoplasm / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000032:analysis / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000502:physiology; D008546:Melanoma, Experimental / Q000276:immunology / Q000628:therapy*; D051379:Mice; D016513:Mice, SCID; D008970:Molecular Weight; D009368:Neoplasm Transplantation; D014183:Transplantation, Heterologous
chemical_list: D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D019496:Cancer Vaccines