Scientific Publications by FDA Staff

Virology 2006 Mar 5;346(1):108-17

The infectivity and host range of the ecotropic porcine endogenous retrovirus, PERV-C, is modulated by residues in the C-terminal region of its surface envelope protein.

Gemeniano M, Mpanju O, Salomon DR, Eiden MV, Wilson CA

Wilson CA, US FDA, Ctr Biol Evaluat & Res, Lab Immunol & Virol, Div Cellular & Gene Therapies, 8000 Rockville Pike,HFM-725,Bldg 29B,Room 2NN12, Bethesda, MD 20892 USA US FDA, Ctr Biol Evaluat & Res, Lab Immunol & Virol, Div Cellular & Gene Therapies, Bethesda, MD 20892 USA Scripps Res Inst, Dept Mol & Expt Med, La Jolla, CA 92037 USA NIMH, Lab Cellular & Mol Regulat, NIH, Bethesda, MD 20892 USA

Endogenous retroviral genetic material serves as a reservoir for the generation of retroviral pathogens by recombination between activated endogenous or exogenous infectious agents. Some porcine tissues actively express infectious porcine endogenous retroviruses (PERVs). Of the three classes of PERV characterized to date, two, PERV-A and B, are capable of infecting human cells in vitro, whereas PERV-C cannot. Here, we demonstrate that the PERV-C envelope surface protein (SU) when disassociated from its C-terminus binds human cells. Further, we show that PERV-C binding to human cells is not inhibited in 293 cells productively infected with PERV-A, confirming that the molecule PERV-C interacts with on human cells is distinct from that used by PERV-A. Moreover, we demonstrate that the envelope region encompassing the proline-rich region is required for binding to cells in addition to the putative variable region A (VRA) and B (VRB). The region in the C-terminus of the SU that alters the binding and infectivity properties of PERV-C differs by only nine residues from the analogous region of PERV-A. Caution may be warranted even when a xenotransplantation product is from source pigs that do not express human-tropic viruses, as minimal mutations within PERV-C combined with selection in a human recipient could render PERV-C infectious in humans.