SAOS-2 cells are resistant to the CD4-independent HIV-1 vector infection.

<p>(A) Transduction titers of the mNDK and VSV-G vectors were measured on 293T, SAOS-2, and C33A cells. Relative values to the titers on 293T cells are indicated. (B) Cathepsin B activities of cell lysates from 293T, HeLa, SAOS-2 and C33A cells were measured by the cathepsin B activity assay kit. (C) Transduction titers of the mNDK vector were measured on DMSO- (Cont.) or CA-074Me-treated SAOS-2 cells. (D) Transduction titers of the mNDK vector were measured on DMSO- (Cont.) or CA-074Me-treated C33A cells. These experiments were repeated 3 times, and the results are shown as the means +− SD. Asterisks indicate statistically significant differences compared to the control cells. (E) Relative values to the cathepsin B activity of SAOS-2 cells (x axis) and to the transduction titer in 293T cells (y axis) are plotted. Correlation between cathepsin B activity and susceptibility to the CD4-independent infection was analyzed by Spearman's rank correlation.