The present invention provides targeted lentiviral vectors that are psuedotyped with mutated Sindbis envelopes. For example, mutations in the Sindbis E2 protein are used to alter viral titer, specificity, specificity index, tropism, and susceptibility to host immune response. Typically, one or more of the E1, E2, or E3 proteins can be mutated at one or more amino acid positions. The psuedotyped, targeted lentiviral vectors of the invention are used to transduce heterologous genes into a cell and can be used for in vivo and ex vivo therapeutic applications, as well as for diagnostic and research tool applications.
