title: Use of spontaneous Epstein-Barr virus-lymphoblastoid cell lines genetically modified to express tumor antigen as cancer vaccines: mutated p21 ras oncogene in pancreatic carcinoma as a model.
abstract: Spontaneous Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (SP-LCLs) can be easily obtained from latently EBV-infected cancer patients and used as a source of antigen-presenting cells (APCs) for immunotherapy. Using point-mutated (codon 12) p21(ras) (muRas) as a model tumor antigen, we evaluated the practicability of using genetically modified SP-LCLs as cancer vaccines for patients with pancreatic cancer expressing mutated Ras (muRas). The repeated stimulation of peripheral blood mononuclear cells (PBMCs) from patients with muRas-LCLs elicited a strong, muRas-specific T cell response. A significant cytotoxic activity against EBV virus proteins or components of the expression vector was not observed. The T cells were able to recognize naturally presented muRas, as shown by their cytotoxicity against muRas (Gly-12 to Val-12 or Asp-12)-expressing tumor cells. The T cell response was mainly MHC class I restricted, and peptides containing amino acids 5 to 14 of muRas-Val-12 and muRas-Asp-12 were identified as immunogenic peptides for HLA-A2. In contrast to the situation in patients with putatively muRas-primed T cells, muRas-LCLs were not able to prime naive T lymphocytes from healthy controls. Vaccination of a pancreatic cancer patient with muRas-LCL induced muRas-specific T cells in PBMCs after 4 weeks. We conclude that genetically modified muRas-LCLs can efficiently present tumor antigens to the immune system and induce antigen-specific cytotoxic T cell responses in vitro and in vivo.
authors.affiliation: Department of Internal Medicine I, University of Saarland Medical School, D-66421 Homburg/Saar, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Kubuschok
authors.forename: Rudolf
authors.initials: R
authors.lastname: Schmits
authors.forename: Frank
authors.initials: F
authors.lastname: Hartmann
authors.forename: Christiane
authors.initials: C
authors.lastname: Cochlovius
authors.forename: Rainer
authors.initials: R
authors.lastname: Breit
authors.forename: Jochem
authors.initials: J
authors.lastname: König
authors.forename: Georg
authors.initials: G
authors.lastname: Pistorius
authors.forename: Martin
authors.initials: M
authors.lastname: Schilling
authors.forename: Christoph
authors.initials: C
authors.lastname: Renner
authors.forename: Michael
authors.initials: M
authors.lastname: Pfreundschuh
mesh_terms: D002277:Carcinoma / Q000628:therapy*; D002460:Cell Line; D003713:Dendritic Cells; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D004854:Herpesvirus 4, Human / Q000235:genetics*; D006801:Humans; D008214:Lymphocytes / Q000821:virology*; D009154:Mutation; D015689:Oncogene Protein p21(ras) / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000628:therapy*; D010455:Peptides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
chemical_list: D010455:Peptides; D015689:Oncogene Protein p21(ras)