title: Serological response of non-human primates to human melanoma disialoganglioside GD3.
abstract: The immunogenicity of the disialoganglioside, GD3, a melanoma-tumor-associated antigen, has been evaluated in non-human primates. Sera from four chimpanzees and two monkeys were evaluated for anti-GD3 antibody activity by solid-phase radioimmunoassay using GD3 and control gangliosides as targets. Serum from one monkey, immunized with cells from a melanoma cell line, was strongly reactive with GD3, having a titer of greater than 2500. In contrast, serum from this animal was non-reactive with several other gangliosides including the structurally similar GM3. Anti-GD3 reactivity was also demonstrable, albeit in low titer, in the sera of an additional monkey and a chimpanzee. Each of these animals had likewise been immunized using cells from melanoma cell lines. On the basis of these observations, suggestive of a primate anti-GD3 antibody response, we initiated a series of immunizations of chimpanzee using purified GD3 bound to Salmonella minnesota, R595. IgG reactive with melanoma cells in the cell-binding assay was first detected in sera collected after 4 immunizations and increased in titer against each reactive melanoma cell line during the immunizations. Reactivity of this serum with melanoma cell lines demonstrated a direct correlation with the expression of GD3 by the respective cell line. Anti-GD3 reactivity was evident in solid-phase radioimmunoassay against purified GD3 beginning with serum collected after 11 immunizations. By comparison with its binding to the control ganglioside panel, this serum demonstrated strong specificity for GD3 (titer = 640) while having only marginal reactivity with GM3 (titer = 40). Immune serum from this animal was also able specifically to block subsequent binding of a murine IgM anti-GD3 antibody (DMab7) to target GD3 in solid-phase radioimmunoassay. Together, these observations suggest that GD3, in the form of a purified molecule bound to a bacterial matrix or as part of the intact melanoma cell membrane, can be immunogenic in non-human primates, and is able to elicit an antibody response of appropriate specificity.
authors.affiliation: Department of Surgery, Duke University Medical Center, Durham, NC 27710.
authors.forename: G M
authors.initials: GM
authors.lastname: Stuhlmiller
authors.forename: K M
authors.initials: KM
authors.lastname: Roberson
authors.forename: H F
authors.initials: HF
authors.lastname: Seigler
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology*; D005732:Gangliosides / Q000276:immunology*; D006801:Humans; D008251:Macaca / Q000276:immunology*; D008253:Macaca mulatta / Q000276:immunology*; D008546:Melanoma, Experimental / Q000276:immunology*; D009368:Neoplasm Transplantation; D002679:Pan troglodytes / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D005732:Gangliosides; C026226:ganglioside, GD3