Methods of delivering a cargo moiety to a cell is provided that include contacting a cell expressing sialoadhesin with a conjugate including a sialoadhesin binding moiety and a cargo moiety. The sialoadhesin binding moiety binds to the sialoadhesin expressed by the cell and is internalized along with the cargo, delivering the cargo moiety to the cell. Particular methods include induction or enhancement of sialoadhesin expression in a cell which naturally produces little or no sialoadhesin. Induction or enhancement of sialoadhesin expression includes transfection of a sialoadhesin expression construct and/or administration of an agent effective to induce or enhance sialoadhesin expression. Methods and compositions for stimulating an immune response in a subject are detailed. Particular methods and compositions for stimulating an immune response to a virus are provided herein.
