The present invention is in relation to a kind of mammalian cell by the virion (HCMV) discharged after human cytomegalovirus infection, wherein a) particle by being wherein embedded in lipid membrane viral glycoprotein, b) particle had both been free of viral DNA or not capsid C) particle contains the T cell antigen pp65 and at least one heterologous polypeptide that fusion protein includes one or more parts, wherein at least one heterologous peptides is inserted into the T cell antigen pp65 of the amino acid sequence of amino acid position W175 or A534.
