Antigen modified cancer cell vaccines for cancer therapy

Patent Number: 7,348,015

This patent covers a way of "controlling or inhibiting blastoma cancer cell proliferation in a mammal" by vaccinating with tumor cells that express the Streptococcus pyogenes gene emm55.  The natural function of emm55 appears to be in immune evasion of the complement system.  Since tumor cells have mammalian complement inhibitory proteins, maybe the approach proposed by the patent stimulates cross-reactive immunity in the mammal against the immune inhibitory protein and its mammalian analogue.

The patent also covers the transfection of the tumor cells with human allogeneic HLA-II.

It is very interesting that bacterial genes are being used for stimulation of anticancer immunity.  Near the end of the 19th Century William Coley performed similar types of anti-cancer immune stimulation using various bacterial mixtures.  This approach is currently being perfected by the Canadian company MBVax who has already treated 38 advanced cancer patients and reported regressions in 24 of them.

Success of any of these cancer immunotherapies will depend on the ability to stimulate immune responses that can effectively target the cancer stem cell.  Unfortunately cancer stem cells appear to also have higher expression of immune suppressive molecules as compared to progeny cancer cells.  Maybe by combining approaches such as cancer stem cell specific antibodies together with activators of innate immunity, we will see preferential uptake and immune activation against epitopes selective to the cancer stem cell.

View this patent on the USPTO website.