Cystatin C was isolated as an enhancer of the CD4-independent mNDK HIV-1 vector infection.
(A) A blasticidin resistance gene-bearing mNDK HIV-1 vector was inoculated into the cDNA expression library-transfected HeLa cells, and blasticidin-resistant cell clones were isolated. Transduction titers of the LacZ gene-bearing mNDK HIV-1 vector were measured on these blasticidin-resistant cell clones. Relative values to the transduction titer on normal HeLa cells are indicated. This experiment was repeated 3 times, and the results are shown as the means +− SD. Asterisks indicate statistically significant differences compared to the relative value on HeLa cells. (B) PCR was performed using genomic DNA samples prepared from the HmN-2 cells. The PCR products were subjected to agarose gel electrophoresis. (C) A cell lysate prepared from the HmN-2 cells was analyzed by Western immunoblotting using an anti-cystatin C (upper panel) or anti-actin (lower panel) antibody. (D) To detect cystatin C or GAPDH mRNA, RT-PCR was performed. The PCR products were subjected to agarose gel electrophoresis.