title: Consistent antibody response against ganglioside GD2 induced in patients with melanoma by a GD2 lactone-keyhole limpet hemocyanin conjugate vaccine plus immunological adjuvant QS-21.
abstract: OBJECTIVE
  Melanomas, sarcomas, and neuroblastomas abundantly express the ganglioside GD2 on the cell surface where it is susceptible to immune attack by antibodies. Overexpression of GD2 on these tumors is striking, as is the frequency of clinical responses after treatment of neuroblastoma with monoclonal antibodies against GD2. In addition, preclinical models have demonstrated the ability of a GD2-keyhole limpet hemocyanin (KLH) conjugate vaccine to induce antibodies that eliminate micrometastases. However, vaccination of patients with GD2-KLH has previously failed to induce a consistent relevant antibody response. We test here whether the use of GD2 lactone-KLH can overcome the low immunogenicity of GD2-KLH.
  
  
  METHODS
  Eighteen patients with melanoma were vaccinated s.c. in the adjuvant setting on weeks 0, 1, 2, 3, 10, and 24. Groups of 6 patients were entered at three dose levels (3, 10, or 30 micro g) of GD2 lactone (GD2L) in vaccines containing GD2L-KLH plus the immunological adjuvant QS-21. Blood was drawn at regular intervals to assess the antibody response.
  
  
  RESULTS
  The vaccine was well tolerated. The majority of patients in all three dose levels produced anti-GD2 antibodies detectable by ELISA assay. Specificity for GD2 was also confirmed by immune thin-layer chromatography. Although there was no statistical difference in terms of titers between the three groups, patients at the 30- micro g dose level had higher titers and longer lasting antibody responses overall by ELISA (median IgM/IgG peak titer 1:640/1:80) and generated the strongest cell surface reactivity by fluorescence-activated cell sorting (median IgM peak percentage positive cells/mean fluorescence intensity for pre- and postvaccination sera is 10%/63 and 70%/135). Patients vaccinated with the 30- micro g GD2 dose also had the most potent complement dependent cytotoxicity using human complement, with 5 of 6 patients showing strong cell surface reactivity by fluorescence-activated cell sorting and >30% cytotoxicity by chromium release with a serum dilution of 1/100.
  
  
  CONCLUSIONS
  GD2L-KLH conjugate vaccine plus adjuvant QS-21 induces antibodies against GD2 that bind to the cell surface and induce complement-dependent cytotoxicity in the majority of patients with melanoma.
authors: Laboratory of Tumor Vaccinology, Clinic Immunology Service, Department of Medicine Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. ragupatg@mskcc.org
authors: Govind
authors: G
authors: Ragupathi
authors: Philip O
authors: PO
authors: Livingston
authors: Chandra
authors: C
authors: Hood
authors: John
authors: J
authors: Gathuru
authors: Susan E
authors: SE
authors: Krown
authors: Paul B
authors: PB
authors: Chapman
authors: Jedd D
authors: JD
authors: Wolchok
authors: Linda J
authors: LJ
authors: Williams
authors: Roberta C
authors: RC
authors: Oldfield
authors: Wen-Jen
authors: WJ
authors: Hwu
mesh_terms: D000276:Adjuvants, Immunologic; D000917:Antibody Formation; D000918:Antibody Specificity; D000920:Antibody-Dependent Cell Cytotoxicity; D019496:Cancer Vaccines / Q000627:therapeutic use*; D004797:Enzyme-Linked Immunosorbent Assay; D005732:Gangliosides / Q000276:immunology*; D006433:Hemocyanins / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology; D007783:Lactones / Q000276:immunology / Q000378:metabolism; D008545:Melanoma / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D012503:Saponins / Q000276:immunology / Q000627:therapeutic use; D012878:Skin Neoplasms / Q000276:immunology / Q000556:secondary / Q000628:therapy; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000627:therapeutic use*
chemical_list: D000276:Adjuvants, Immunologic; D019496:Cancer Vaccines; D005732:Gangliosides; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007783:Lactones; D012503:Saponins; D018074:Vaccines, Conjugate; C078785:saponin QA-21V1; C019403:ganglioside, GD2; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin