title: Increased vaccination efficiency with apoptotic cells by silica-induced, dendritic-like cells.
abstract: We have demonstrated previously the ability of apoptotic cells to prime a functional immune response using an i.p. vaccination protocol with apoptotic cells and interleukin 2, before injecting a lethal dose of tumor cells into syngeneic rats. This protocol resulted in a survival rate of 33%. To elucidate the nature and the activity of the phagocytes involved in the clearance of apoptotic cells in vivo, we modulated the peritoneal cavity environment by administrating either thioglycollate or silica i.p. before injecting the apoptotic cells. Our results showed that thioglycollate abrogated vaccination efficiency, because none of the rats survived under these conditions. In fact, thioglycollate treatment induced a massive recruitment and activation of inflammatory macrophages that efficiently engulfed apoptotic cells, bypassing induction of specific immune responses. In contrast, silica treatment enhanced the vaccination efficiency of apoptotic cells plus interleukin 2 up to 66%. We distinguished a population of dendrite-like cells among the cells derived from the silica-treated peritoneal cavity both by their phenotype (MHC II(+)/CD80(+)/CD86(+)) and by their ability to induce the proliferation of allogeneic T cells in a mixed leukocyte reaction. Our results demonstrate the different roles of macrophages and dendritic-like cells in the physiological clearance of dead tumor cells and their implication in the design of immunomodulating vaccines.
authors.affiliation: INSERM U419, Institut de Biologie, 44093 Nantes cedex 01, France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Massé
authors.forename: Cécile
authors.initials: C
authors.lastname: Voisine
authors.forename: Frédéric
authors.initials: F
authors.lastname: Henry
authors.forename: Sandrine
authors.initials: S
authors.lastname: Cordel
authors.forename: Isabelle
authors.initials: I
authors.lastname: Barbieux
authors.forename: Regis
authors.initials: R
authors.lastname: Josien
authors.forename: Khaled
authors.initials: K
authors.lastname: Meflah
authors.forename: Marc
authors.initials: M
authors.lastname: Grégoire
authors.forename: Blandine
authors.initials: B
authors.lastname: Lieubeau
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology*; D003110:Colonic Neoplasms / Q000276:immunology* / Q000628:therapy; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D016219:Immunotherapy, Adoptive; D007376:Interleukin-2 / Q000276:immunology / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology; D010529:Peritoneal Cavity / Q000166:cytology; D010587:Phagocytosis / Q000276:immunology; D051381:Rats; D011917:Rats, Inbred Lew; D012822:Silicon Dioxide / Q000276:immunology / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology; D013864:Thioglycolates / Q000276:immunology / Q000494:pharmacology
chemical_list: D019496:Cancer Vaccines; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2; D013864:Thioglycolates; D012822:Silicon Dioxide