The present invention relates to cells engineered to express at least one cytokine and at least one antigen which induces the self differentiation of dendritic cell (DC) progenitor cells into functional antigen-presenting induced DC (iDC). Moreover, therapeutic uses of said iDC for regenerating the immune system after transplantation of hematopoietic stem cells are disclosed. Said iDC are also useful for generating mice with a functional endogenously regenerated humanized immune system producing antigen-specific T and B cell responses which can be used as animal models for the study of the human adaptive immune responses.