Disclosed is a method to obtain dendritic cells loaded with an exogenously added antigen. The method is in particular applicable to human cell lines that may be used in the production of dendritic cell vaccines, e.g. to be used in the treatment of cancer. In the method the antigen to be loaded on the cells is added to the cells at particular stages of the development of the dendritic cells. A pharmaceutical composition comprising the obtained cells is also disclosed.