Schematic structure of rVSVs expressing HTLV-1 receptor molecule(s). The gene orders in the rVSV constructs used in this study and wild-type construct are illustrated. The VSVΔG construct lacks the VSV G gene, which encodes a VSV envelope glycoprotein. The deleted G gene was replaced with human GLUT1, NRP1, or SDC1 genes, yielding the VSVΔG-GL, VSVΔG-NP, or VSVΔG-SD constructs, respectively. In addition, a human NRP1 gene was inserted downstream of the GLUT1 gene in VSVΔG-GL, yielding VSVΔG-GLN. The human SDC1 gene was inserted downstream of the NRP1 gene in VSVΔG-GLN, yielding VSVΔG-GLNS.