title: Comparative analysis of cancer vaccine settings for the selection of an effective protocol in mice.
abstract: BACKGROUND
  Cancer vaccines are considered a promising therapeutic approach. However, their clinical results are not yet satisfactory. This may be due to the the difficulty of selection of an efficient tumor associated antigen (TAA) and immunization protocol. Indeed, the weak antigenicity of many TAA impairs the design of robust procedures, therefore a systematic analysis to identify the most efficient TAA is mandatory. Here, we performed a study to compare different gp100 vaccination strategies to identify the best strategy to provide a 100% protection against experimental melanoma in a reproducible manner.
  
  
  METHODS
  C57BL/6J mice were challenged subcutaneously with B16F10 melanoma cells, after vaccination with: a) mouse or human gp10025-33 peptide plus CpG adjuvant; b) mouse or human gp100 gene; c) mouse or human gp10025-33 peptide-pulsed dendritic cells (DC). Alternatively, a neutralizing anti-IL-10 monoclonal antibody (mAb) was subcutaneously administered at the site of tumor challenge to counteract regulatory cells. Finally, combinatorial treatment was performed associating human gp10025-33 peptide-pulsed DC vaccination with administration of the anti-IL-10 mAb.
  
  
  RESULTS
  Vaccination with human gp10025-33 peptide-pulsed DC was the most effective immunization protocol, although not achieving a full protection. Administration of the anti-IL-10 mAb showed also a remarkable protective effect, replicated in mice challenged with a different tumor, Anaplastic Large Cell Lymphoma. When immunization with gp10025-33 peptide-pulsed DC was associated with IL-10 counteraction, a 100% protective effect was consistently achieved. The analysis on the T-cell tumor infiltrates showed an increase of CD4+granzyme+ T-cells and a decreased number of CD4+CD25+Foxp3+ Treg elements from mice treated with either gp10025-33 peptide-pulsed DC vaccination or anti-IL-10 mAb administration. These data suggest that processes of intratumoral re-balance between effector and regulatory T cell subpopulations may play a critical protective role in immunotherapy protocols.
  
  
  CONCLUSIONS
  Here we demonstrate that, in the setting of a cancer vaccine strategy, a comparative analysis of different personalized approaches may favour the unveiling of the most effective protocol. Moreover, our findings suggest that counteraction of IL-10 activity may be critical to revert the intratumoral environment promoting Treg polarization, thus increasing the effects of a vaccination against selected TAA.
authors.affiliation: Centre of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV n. 7, 16132, Genoa, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Kalli
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Machiorlatti
authors.forename: Florinda
authors.initials: F
authors.lastname: Battaglia
authors.forename: Alessia
authors.initials: A
authors.lastname: Parodi
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Conteduca
authors.forename: Francesca
authors.initials: F
authors.lastname: Ferrera
authors.forename: Michele
authors.initials: M
authors.lastname: Proietti
authors.forename: Samuele
authors.initials: S
authors.lastname: Tardito
authors.forename: Marina
authors.initials: M
authors.lastname: Sanguineti
authors.forename: Enrico
authors.initials: E
authors.lastname: Millo
authors.forename: Daniela
authors.initials: D
authors.lastname: Fenoglio
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Palma
authors.forename: Giorgio
authors.initials: G
authors.lastname: Inghirami
authors.forename: Gilberto
authors.initials: G
authors.lastname: Filaci
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001854:Bone Marrow Cells / Q000166:cytology; D019496:Cancer Vaccines / Q000627:therapeutic use*; D018899:CpG Islands; D003713:Dendritic Cells / Q000166:cytology; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D016753:Interleukin-10 / Q000276:immunology; D008545:Melanoma / Q000188:drug therapy*; D008546:Melanoma, Experimental; D051379:Mice; D008810:Mice, Inbred C57BL; D015203:Reproducibility of Results; D013154:Spleen / Q000378:metabolism; D014611:Vaccination; D058951:gp100 Melanoma Antigen / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D019496:Cancer Vaccines; D058951:gp100 Melanoma Antigen; D016753:Interleukin-10