Figure 1

The N-terminal Slit2 fragment possesses anti-HIV-1 activity. (A) Domain organization of Slit2 showing LRR, leucine-rich repeat; EGF, epidermal growth factor-like; LG, laminin G-like; CT, C-terminal cystine regions. (B) Silver staining of the Slit2N protein. (C) MT4 cells pre-treated with various concentrations of Slit2N were infected with HIV-1 IIIB (10 ng p24). We used heat-inactivated (H.I) Slit2N as a control. After 48 hours, supernatants were collected for estimation of HIV-1 p24 antigen levels by ELISA. Virus production in the positive control (control HIV-1 infected MT4 cells): 4.8 ng/ml p24 Ag. Heat-inactivated Slit2N at a concentration of 60nM was used as a control. (D) MT4 cells were treated with Slit2-N (6 nM) for 30 minutes and then infected with HIV-Luc viruses pseudotyped with VSV-G envelope (VSV-G) for 2 hours. Forty-eight hours post infection, cells were harvested for the Luciferase assay. (E) MT4 cells were treated with equivalent concentrations of Slit2N and Slit2 ΔD2 (≈6nM) and infected with HIV-1 IIIB (10 ng p24) for 48 hours. Virus production in the supernatants was estimated by HIV-1 p24 ELISA. (F) MT4 cells infected with HIV-1 IIIB were co-cultured with dye-labeled target Jurkat T-cells in the presence of various concentrations of Slit2N for 4 hours, and the percentage of Gag⁺ target cells was measured by flow cytometry. The results are represented in a bar graph. Values are the mean percentages of Gag⁺ dye-labeled target cells with the SEMs. Infected cells were used when >70-80% of the donor cells were routinely Gag⁺ by flow cytometry. Data are representative of three independent experiments. *P ≤ 0.05 versus untreated cells.