Disclosed are compositions comprising a recombinant nucleic acid vector including a nucleotide sequence encoding a syncytium-inducing polypeptide expressible on a eukaryotic cell surface, and a host cell containing the recombinant vector and expressing the syncytium inducing polypeptide on its cell surface, the vectors and resultant host cells expressing the syncytium inducing polypeptide being useful for selective elimination of unwanted cells.