The present invention relates to a pharmaceutical composition containing blood cells or haemopoietic cells, e.g. red blood cells (erythrocytes), granulocytes, mononuclear cells (PBMCs) and/or blood platelets, in combination with a pharmaceutically acceptable excipient and/or vehicle, wherein the cells are transfected with at least one mRNA comprising at least one region coding for at least one antigen. The invention further discloses a method of preparing the aforesaid pharmaceutical composition and the use of blood cells transfected in this way for the preparation of drugs or pharmaceutical compositions for immune stimulation against the antigens encoded by the mRNA. The subjects according to the invention are used especially for the therapy and/or prophylaxis of carcinoses or infectious diseases and can also be employed in gene therapy.
