I thought that the objective with Tysabri treatment was to simply block the immune system from getting into the brain.
You're correct, Tysabri is a humanized monoclonal antibody that binds to an alpha-integrin which is a protein involved in the mechanism of how the T-cells cross from the bloodstream into the central nervous system (the brain and spinal cord). So in a nutshell, Tysabri works by keeping the bad cells of your immune system from getting to your nerve cells to do damage.
Campath, on the other hand, is a humanized monoclonal antibody that binds to a protein called CD-52 that is present on B-cells and T-cells along with a few monocytes and macrophages. When it binds to these cells it starts a chain reaction that results in the death of that cell. This is how it accomplishes the immune system "reboot." So, Campath's mechanism of action is to address the root cause of MS, a screwed up immune system, rather than trying to make a screwed up immune system play nice as do the CRABS and Tysabri.
I was a Tovaxin lab rat and will find out on February 19 if I'm randomized to the Campath or Rebif arm of the MS CARE-II study. I started my MS journey on Betaseron and didn't do well on it so the thought of Rebif is not very comforting. All I can do though is deal with the situation as it evolves but in the end I have to do what is best for me and my family.