HIV-Derived Vectors for Gene Therapy Targeting Dendritic Cells

Safety markers for rhabdomyosarcoma cells using an in vivo imaging system

In vivo imaging system (IVIS) is a novel and rapidly expanding technology that is widely applied in life sciences, including cell tracing. IVIS is able to quantify biological events, including tumor proliferation, through counting the number of photons emitted from a specimen. PLA802-enhanced green fluorescent protein (EGFP), PLA802-monomeric cherry fluorescent protein (mCherry), RH30-EGFP and RH30-mCherry tumor cells were injected into 18 BALB/c female nude mice subcutaneously with 5×10⁶ cells in 100 µl to quantitatively analyze EGFP and mCherry cells traced by IVIS. Inversion fluorescence microscopy revealed no transfection efficiency difference between PLA802-EGFP (95.3±1.2%) and PLA802-mCherry (95.8±1.7%), or between RH30-EGFP (94.7±2.1%) and RH30-mCherry (95.2±1.9%). Transfection did not influence the cell morphology of PLA802 or RH30. The cell migration, invasion and proliferation assay results of lentivirus-EGFP and lentivirus-mCherry revealed no significant difference prior to or following transfection. Therefore, lentivirus-EGFP and lentivirus-mCherry may serve as safety biological markers for PLA802 and RH30 cells. In vivo experiments demonstrated that lentivirus-EGFP and lentivirus-mCherry tumor luminescence signals were observed in all mice by IVIS. Hematoxylin-eosin staining and immunohistochemistry indicated that PLA802-EGFP, PLA802-mCherry, RH30-EGFP and RH30-mCherry cell lines exhibited rhabdomyosarcoma (RMS) characteristics like the maternal cells. In summary, mCherry and green fluorescent protein in human RMS PLA802 and RH30 cancer cells may be safely and stably expressed for a long time in vitro and in vivo.

Risks Associated With Lentiviral Vector Exposures and Prevention Strategies

Lentiviral vectors (LVVs) are powerful genetic tools that are being used with greater frequency in biomedical laboratories and clinical trials. Adverse events reported from initial clinical studies provide a basis for risk assessment of occupational exposures, yet many questions remain about the potential harm that LVVs may cause. We review those risks and provide a framework for principal investigators, Institutional Biosafety Committees, and occupational health professionals to assess and communicate the risks of exposure to staff. We also provide recommendations to federal research and regulatory agencies for tracking LVV exposures to evaluate long-term outcomes. U.S. Food and Drug Administration approved antiviral drugs for HIV have theoretical benefits in LVV exposures, although evidence to support their use is currently limited. If treatment is appropriate, we recommend a 7-day treatment with an integrase inhibitor with or without a reverse transcriptase inhibitor within 72 hours of exposure.