title: Immunization against endogenous retroviral tumor-associated antigens.
abstract: Endogenous retroviral gene products have been found in some human tumors, and therefore, may serve as antigens for immunotherapy approaches. The murine colorectal carcinoma CT26 and melanoma B16 have recently been found to express the endogenous retroviral gene products gp70 and p15E, respectively, that can serve as antigens recognized by T cells. To date, though, there has been no demonstration of tumor treatment using an endogenous retroviral protein. In this study, we demonstrate that mice immunized with recombinant vaccinia encoding the gp70 H2-L(d)-restricted minimal determinant were protected from CT26 tumor challenge. Splenocytes from mice immunized with vaccinia gp70 specifically secreted IFN-gamma in response to gp70 peptide-pulsed stimulators. Although this strategy could protect against subsequent tumor challenge, it was ineffective against established tumors. Therefore, to investigate the treatment of established CT26 or B16 lung metastases, mice were treated with cultured dendritic cells (DCs) pulsed with gp70 or p15E peptide. Significant inhibition of established lung metastases required immunization with peptide-pulsed DCs pretreated with CD40 ligand that has been demonstrated to increase the T-cell stimulatory activity of DCs. The ability to immunize against endogenous retroviral tumor antigens may have relevance in the induction of antitumor immunity for some human cancers.
authors.affiliation: Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Kershaw
authors.forename: C
authors.initials: C
authors.lastname: Hsu
authors.forename: W
authors.initials: W
authors.lastname: Mondesire
authors.forename: L L
authors.initials: LL
authors.lastname: Parker
authors.forename: G
authors.initials: G
authors.lastname: Wang
authors.forename: W W
authors.initials: WW
authors.lastname: Overwijk
authors.forename: R
authors.initials: R
authors.lastname: Lapointe
authors.forename: J C
authors.initials: JC
authors.lastname: Yang
authors.forename: R F
authors.initials: RF
authors.lastname: Wang
authors.forename: N P
authors.initials: NP
authors.lastname: Restifo
authors.forename: P
authors.initials: P
authors.lastname: Hwu
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology*; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D023201:CD40 Ligand / Q000276:immunology; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology*; D003110:Colonic Neoplasms / Q000628:therapy; D003713:Dendritic Cells / Q000276:immunology; D016219:Immunotherapy, Adoptive; D008175:Lung Neoplasms / Q000556:secondary / Q000628:therapy; D008546:Melanoma, Experimental / Q000556:secondary / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D015682:Retroviridae Proteins, Oncogenic / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D019496:Cancer Vaccines; D015682:Retroviridae Proteins, Oncogenic; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; C078678:p15E protein, Murine leukemia virus; D023201:CD40 Ligand