Ampho-, Poly-, Xeno-, and XMRV-MLV vector infections require endosome acidification and cathepsin proteases.

<p>(A) TE671, TE671/mCAT1, or TE671/CD4 cells were pretreated with ConA for 5 h and were inoculated with the Eco-, Ampho-, Poly-, Xeno-, XMRV-MLV, or HXB2-HIV-1 vector. (B) TE671 or TE671/CD4 cells were pretreated with BFLA-1, and were inoculated with the Ampho-, Poly-, Xeno-, VSV-, XMRV-, VSV-MLV, or HXB2-HIV-1 vector. (C) TE671 or TE671/mCAT1 cells were pretreated with CA-074Me and were inoculated with the Eco-, Ampho-, Poly-, Xeno-, VSV-, or XMRV-MLV vector. The transduction units obtained with DMSO-treated cells were set to 100%. These experiments were repeated in triplicate, and results are shown as the mean +/− SD. Asterisks indicate statistically significant differences compared to the value from the DMSO-treated cells. (D) Cathepsin B activity of cells lysates from CA-074Me-treated cells was measured. Fluorescence intensities are shown. XC cells were treated with ConA (panel E) or CA-074Me (panel F), and were inoculated with the Eco-, Ampho-, Poly-, Xeno-, XMRV-, or VSV-MLV vector. These experiments were repeated in triplicate, and results are shown as the mean +/− SD. Asterisks indicate statistically significant differences compared to the value from the DMSO-treated cells. (G) Activities of cathepsins B (left panel) and L (right panel) were measured in cell lysates from XC, NIH3T3, 293T, and TE671 cells. Fluorescence intensities were indicated. These experiments were repeated three times, and results are shown as the mean +/− SD.