Comparison of efficiency of infection of human gene therapy target cells via four different retroviral receptors.

The relative efficiency of transduction of gene therapy target cells was measured for retroviruses bearing the envelopes of amphotropic murine leukemia virus (MLV-A), xenotropic murine leukemia virus (MLV-X), gibbon ape leukemia virus (GALV), feline leukemia virus subgroup B (FeLV-B), and the feline endogenous virus RD114. These viruses use various cell-surface receptors. Activated peripheral blood lymphocytes (PBL) and primary melanoma cultures were infected relatively poorly by MLV-X pseudotypes. RD114 pseudotypes infected PBL relatively well, whereas bone marrow progenitor cells were efficiently infected by all viruses. Helper-free virus bearing the envelopes of MLV-A, RD114, or GALV was similarly tested. All infected melanoma or bone marrow progenitor cells efficiently, whereas MLV-A was relatively inefficient for infection of PBL. The general utility of RD114 pseudotyped virus for gene delivery coupled with its resistance to inactivation by human serum makes this envelope the most suitable choice for in vivo gene therapy.