title: Dendritic-tumor cell hybrids induce tumor-specific immune responses more effectively than the simple mixture of dendritic and tumor cells.
abstract: OBJECTIVE
  Dendritic cell (DC)-tumor cell hybrids have been used clinically in cancer immunotherapy, but their advantage over the simple mixture of tumor cells and DCs is still a matter of controversy. In this study, we compared DC-tumor cell hybrids with the non-fused mixture of DC and tumor cells directly in their ability to induce a specific immune response.
  
  
  METHODS
  Hybrids were obtained by electrofusion of tumor cells and monocyte-derived DCs. Cell phenotype was evaluated by flow cytometry and antigen-presenting ability by co-culture with syngeneic T cells followed by tetramer analysis and interferon (IFN)-γ ELISPOT.
  
  
  RESULTS
  Less than half the cells in the mixture expressed DC co-stimulatory molecules. Furthermore, DCs in the mixture had significantly lower expression of MHC class I molecules than DCs in the fusion. Conversely, nearly all CD11c(+)Her2/neu(+) hybrids expressed CD80, CD86, CD83, HLA-DR and MHC class I from both tumor cells and DCs. Using tumor cells constitutively expressing a cytomegalovirus (CMV) antigen, we show that expansion of CMV-specific cytotoxic T lymphocytes (CTLs) restricted by DCs' MHC class I molecules was higher when DC-tumor hybrids were the stimulators. Furthermore, only hybrids stimulated CTLs to produce IFN-γ in response to CMV-positive target cells.
  
  
  CONCLUSIONS
  These data show the superiority of DC-tumor cell hybrids over their simple mixture as T-cell stimulators. Hybrids expressed more co-stimulatory and MHC molecules, induced higher antigen-specific T-cell expansion and were the only cells able to induce IFN-γ-producing antigen-specific T cells. Thus, these data offer further support for cancer immunotherapeutic approaches using DC-tumor cell hybrids.
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Mariana Pereira
authors.initials: MP
authors.lastname: Pinho
authors.affiliation: Rebirth Excellence Cluster and Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany.
authors.forename: Bala Sai
authors.initials: BS
authors.lastname: Sundarasetty
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Patricia Cruz
authors.initials: PC
authors.lastname: Bergami-Santos
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Karen
authors.initials: K
authors.lastname: Steponavicius-Cruz
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Adilson Kleber
authors.initials: AK
authors.lastname: Ferreira
authors.affiliation: Rebirth Excellence Cluster and Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany.
authors.forename: Renata
authors.initials: R
authors.lastname: Stripecke
authors.affiliation: Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil; Cell and Molecular Therapy Center, NUCEL-NETCEM, University of São Paulo, São Paulo, Brazil. Electronic address: jbarbuto@icb.usp.br.
authors.forename: José Alexandre M
authors.initials: JA
authors.lastname: Barbuto
mesh_terms: D017951:Antigen Presentation; D019496:Cancer Vaccines / Q000276:immunology; D002459:Cell Fusion; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000473:pathology; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D006822:Hybrid Cells / Q000276:immunology* / Q000473:pathology; D007111:Immunity, Cellular; D007167:Immunotherapy / Q000379:methods*; D009369:Neoplasms / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D015395:Histocompatibility Antigens Class I
keywords: cancer vaccines; cell fusion; dendritic cells; hybrid cells; immunotherapy