Patent ID: 7919309

Claim:
A method of expressing an siRNA within a cell, the method comprising: transfecting a packaging cell line with a retroviral construct; recovering a recombinant retrovirus from the packaging cell line; and infecting a target cell in vitro with the recombinant retrovirus; wherein the recombinant retrovirus construct comprises the R and U5 sequences from a 5′ lentiviral long terminal repeat (LTR) and a self-inactivating lentiviral 3′ LTR, a first RNA polymerase III promoter region, a first RNA coding region encoding a first siRNA, and a first termination sequence; wherein the first RNA polymerase III promoter region and the first RNA coding region are located between the 5′ LTR and the 3′ LTR; and wherein the first RNA coding region comprises a sequence that is at least about 90% identical to a target region of CCR5; wherein the target region is from 15 to 30 nucleotides in length.