Tuesday, August 26, 2008


Adenoviruses are viruses that carry their genetic material in the form of double-stranded DNA. They cause respiratory (especially the common cold), intestinal, and eye infections in humans. When these viruses infect a host cell, they introduce their DNA molecule into the host. The genetic material of the adenoviruses is not incorporated (transient) into the host cell's genetic material. The DNA molecule is left free in the nucleus of the host cell, and the instructions in this extra DNA molecule are transcribed just like any other gene. The only difference is that these extra genes are not replicated when the cell is about to undergo cell division so the descendants of that cell will not have the extra gene. As a result, treatment with the adenovirus will require readministration in a growing cell population although the absence of integration into the host cell's genome should prevent the type of cancer seen in the SCID trials. This vector system has shown real promise in treating cancer and indeed the first gene therapy product to be licensed to treat cancer is an adenovirus.