Syngeneic vs allogeneic cells as antigen source for anti-melanoma vaccination

KEON, SOLEDAD MAC; LEVY, ESTRELLA MARIEL; ROSA WAINSTOK; MORDOH, JOSÉ

Simposio; Keystone Simposia- Cancer Immunology and Immunotherapy: Taking a Place in Mainstream Oncology; 2017

One of the major obstacles to obtaining relevant results in cancer immunotherapy has been the unclear definition of relevant target antigens. It is still uncertain whether an autologous (containing neoepitopes) or allogeneic source of antigen (containing tumorassociated antigens) is better at eliciting potent antitumoral protection. We have previously developed an experimentalantimelanoma vaccine (DCApoNec) consisting of dendritic cells (DC) loaded with syngeneic apoptotic and necrotic murine melanoma cells (ApoNec), which provides longterm antimelanoma protection. Using this vaccine, we have compared the use of syngeneic or allogeneic ApoNec cells as source of antigen, and its effect on DCs and on antitumoral protection. We have determined by qPCR the comparable expression of immunogenic melanocyte differentiation antigens by syngeneic B16F1and allogeneic Cloudman murine cell lines. We have observed a low MHCIexpression by both cell lines. When loading DCs with ApoNec cells obtained by irradiation of these cell lines we observed that 60.3±21.1 % and 71.0±19.4% of CD11c+ cells incorporated B16F1 ApoNec or Cloudman ApoNec cells respectively, but that Cloudman ApoNec cells were more efficient at inducing MHCIIupregulation by CD11c+ cells (p