Our lentiviral vectors are basically derived from HIV-1, but 90% of its components are deleted to greatly enhance the safety and efficacy. The safety-enhancement method is the key claim of the patent.

The feature analysis of our lentiviral vectors and other conventional viral vectors are listed as follows:

Our lentiviral vector system is currently the only vector with NIH approval for distribution.

Lentiviral vectors can be used for nondividing or terminally differentiated cells such as neurons, macrophages, hematopoietic stem cells, retinal photoreceptors, and muscle and liver cells, cell types for which previous gene therapy methods could not be used. Due to above properties, lentiviral vectors are ideal for gene therapeutic applications, pharmaceutical target discovery & validation and functional genomics.

It has been proven that the HIV-1 derived lentiviral vector has an even higher rate of expression in its hosts cells than other retroviruses. HIV-1 derived lentiviral vector is very effective, because it has evolved to infect and express its genes in human helper T cells and other macrophages. The only cells lentiviral vector cannot gain access to are quiescent cells (in the G0 state), because this blocks the reverse transcription step.

Lentiviral vectors can enter most kinds of human cells without triggering immune reactions, making them perfect delivery systems.

Previous gene therapy using retroviral vectors required that cells be dividing, limiting therapy to proliferating cells in vivo or ex vivo. In the ex vivo method, the target cells are removed from the patient's body, treated to stimulate replication and then transduced with the vector before being returned to the patient.

The HIV-based vector can be delivered directly into the body without in vitro manipulations of the patient’s cells. Additionally, lentiviral vectors have been shown to be superior to murine retroviral vectors. Ex vivo manipulations that activate stem cells with growth factors to induce cell division must be carried for the retrovirus to be able to enter the stem cells. However, it has been shown that ex vivo stem cell stimulation is not necessary with lentiviral vectors, so the vectors can be inserted directly into the patient and will find their way to the target cells based on cell membrane receptor proteins.

Scientists can implement lentiviral vectors to modify the hematopoietic stem cell, which has the capacity to self-renew and to differentiate into all of the mature cells of the blood and immune systems. Thus, by introducing therapeutic genes into stem cells, many diseases that affect these systems could be treated.

RNA interference (RNAi) is a gene-specific silencing phenomenon. The successful application of RNAi to mammalian cell system has become a powerful tool for functional genomics; however, for in vivo therapeutic applications, the 3 major barriers are:

• the delivery system
• target specificity
• stable gene suppression

Because of the features and properties of our platform technology, those barriers are easily overcome; thus, lentiviral vector system has become the most powerful tool for gene transfer.