More Cancer Immunotherapy
The broad heading of "immunotherapy" covers a very wide range of efforts to convince the immune system to attack specific cells. Here's another example of using viral vectors to induce immune cells into specific actions: "The researchers used a virus stripped of its disease-causing genes as a vehicle to deliver two therapeutic proteins directly into the [glioblastoma multiforme (GBM)] tumor cells. One protein, FMS like tyrosine kinase 3 ligand (Flt3L), drew dendritic cells into the brain. Another protein, herpes simplex virus type 1 thimidine kinase (HSV1-TK), combined with the antiviral gancyclovir (GCV), killed tumor cells. Dendritic cells clean up debris from dying cells and in the process alert immune system cells of the existence of foreign entities, or antigens - in this case, GBM cells. Newly 'educated' immune system cells then swarm to the tumor cells to destroy them. In an earlier study, [researchers] used HSV1-TK and GCV alone to treat GBM and found that about 20 percent of the animals survived, compared to controls. By adding the dendritic-cell inducing Flt3L, the survival rate jumped to about 70 percent. Systemic immune activity was sustained, even fending off a 're-challenge' with additional tumor cells."
Link: http://www.eurekalert.org/pub_releases/2008-02/cmc-gt021308.php