 CTA IV is an immune checkpoint, but what it does is it helps educate the immune cells how to recognize the tumor. A cancer can adapt and figure out ways to evade that immune system attack and then all of a sudden starts to take hold and start growing. And the idea is, well, how can we get that immune system going again? How can we get them those cells to recognize and to develop a memory? We have memory towards polio and the other things we were vaccinated against. That protects us for the majority of our life and that's what we believe is going on with CTA IV treatment is you're getting patients to develop immunologic memory. After you get that CTA IV antibody, you got this new clonal population of what we call neal antigen T cells. And those are the cells that were boosted with the CTA IV treatment and again that are associated with those patients having long-term benefit and potential cure of their disease.