The invention relates to antigen presenting cells (APCs) that present on their surface a tumor or pathogen antigenic epitope encoded by tumor or pathogen derived RNA, wherein the epitope induces T cell proliferation, wherein said APCs are produced by a method comprising: (i) introducing into a antigen-presenting cell in vitro tumor-derived RNA comprising tumor-specific RNA that encodes an antigen that induces T cell proliferation and tumor immunity； or (ii) introducing into a antigen-presenting cell in vitro pathogen-derived RNA consisting essentially of RNA encoding a pathogen antigen that induces T cell proliferation and an immune response to the pathogen and thereby producing an APC that presents on its surface a tumor or pathogen antigenic epitope encoded by the RNA, wherein the epitope induces T cell proliferation.
