The invention relates to a microorganism with a nucleotide sequence coding for a cell antigen in which the following components are inserted and are expressible: I) a nucleotide sequence coding for at least one epitope of an antigen of a tumor cell and/or a nucleotide sequence for at least one epitope of an antigen that is specific for a tissue cell from which the tumor originates； II) an optional nucleotide sequence coding for a protein that stimulates cells of the immune system； IIIA) a nucleotide sequence for a transport system which makes it possible to express the expression product of components I) and, optionally, II) on the outer surface of the bacterium and/or secrete the expression product of component I) and, optionally, of component II)； and/or IIIB) a nucleotide sequence for a protein used for lysing the microorganisms in the cytosol of mammalian cells and for intracellularly releasing plasmids which are contained in the lysed microorganisms； and IV) an activation sequence for expressing one or several of components I) to IIIB), said activation sequence being selected among the group consisting of an activation sequence which is capable of being activated in the microorganism, is tissue-cell-specific but not cell-specific. Each of components I) to IV) can be identically or differently arranged in an individual or multiple manner. Also disclosed are uses of such a microorganism for the production of a medicament.
