title: Immune responsiveness to a murine mammary carcinoma modified to express B7-1, interleukin-12, or GM-CSF.
abstract: This report characterizes the immunological host response to a syngeneic murine mammary carcinoma along with variants genetically modified to express B7-1 or secrete GM-CSF and interleukin-12 (IL-12). MT-901 is a subline of a mammary adenocarcinoma that was chemically induced in the Balb/c host. It was found to be weakly immunogenic by immunization/ challenge experiments, and it induced tumor-specific T-cell responses in lymph nodes (LN) draining progressive subcutaneous tumors. Tumor clones expressing B7-1 or secreting GM-CSF exhibited reduced tumorigenicity without completely abrogating tumor growth, whereas IL-12 elaboration lead to complete tumor growth inhibition. In vivo subcutaneous inoculation of a transgenic cell clone secreting GM-CSF (240 ng/10(6) cells/24 hours) resulted in significantly enhanced T-cell reactivity of tumor-draining lymph node (TDLN) cells as compared to wild-type TDLN cells. This finding was obtained from observations assessed by several different methods, including: 1) in vitro cytotoxicity, 2) in vitro interferon-gamma release, and 3) adoptive transfer in mice with established tumor. Moreover, the transfer of activated LN cells derived from mice inoculated with GM-CSF-secreting tumor cells resulted in the prolonged survival of animals with macroscopic metastatic disease, which was not evident utilizing LN cells from mice inoculated with wild-type tumor. By contrast, clones that expressed B7-1 or IL-12 (4 ng/10(6) cells/24 hours) did not elicit enhanced tumor-reactive TDLN cells compared with wild-type tumor when assessed in the adoptive transfer model. The autocrine secretion of GM-CSF by transduced tumor cells was found to serve as an effective immune adjuvant in the host response to this weakly immunogenic tumor.
authors.affiliation: Division of Surgical Oncology, University of Michigan, Ann Arbor, USA.
authors.forename: E
authors.initials: E
authors.lastname: Aruga
authors.forename: A
authors.initials: A
authors.lastname: Aruga
authors.forename: M J
authors.initials: MJ
authors.lastname: Arca
authors.forename: W M
authors.initials: WM
authors.lastname: Lee
authors.forename: N S
authors.initials: NS
authors.lastname: Yang
authors.forename: J W
authors.initials: JW
authors.lastname: Smith
authors.forename: A E
authors.initials: AE
authors.lastname: Chang
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology*; D000818:Animals; D018122:B7-1 Antigen / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016219:Immunotherapy, Adoptive; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D008175:Lung Neoplasms / Q000276:immunology / Q000556:secondary / Q000628:therapy; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008212:Lymphocyte Depletion; D008325:Mammary Neoplasms, Experimental / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D018122:B7-1 Antigen; D018664:Interleukin-12; D016178:Granulocyte-Macrophage Colony-Stimulating Factor