From what I understand, there are several players in the immune system. The dendritic cells activate the helper T cells, Killer T-Cells and B-Cells. The B-Cells give rise to antibodies that also attack the cancer. Macrophages are a lot like dendritic cells, but they do not present antigens as well to the above players. There are many more aspects and players in the immune response.
One way, but not the only way cancer tricks Killer T-Cells is to shut of their ability to inject their tumor killer toxin into the cancer by blocking the PD-1 antigen on the T-cell with their PD-L1.
Biologiques that block the tumor from doing this make the Killer T-cells more effective at killing tumors, but it is not enough. The cancer uses other techniques.
The key to DCVax is that:
1. Dendritic cells are exponentially grown outside the body.
2. They are grown to their most potent stage.
(If they are too young, they can't effectively express antigens to the Killer T-cells, helper T-cells and B-cells. If the dendritic cells are too old, they can't effectively uptake the antigens and thus are also ineffective. I may have that reversed)
3. In the case of L, the tumor is presented to them outside the body and then re-injected. (despite best practice, it is difficult to get a tumor to present all antigens once it is effectively dead)
4. In the case of direct, the perfect stage dendritic cells are presented to the live tumor by "direct" injection, and thus all antigens are presented to the dendritic cells -- once the tumor recedes the injections are placed into the blood stream (like a flu shot).
5. The perfectly staged dendritic cells create the most potent killer t cells and helper t-cells, and they go after every antigen expressed by the tumor. The DC's do this through up regulation and presenting the other immune system cells with the full set of antigens on the tumor to attack.
6. The perfectly staged dendritic cells also activate the B-cells to create the broadest set of antibodies. It is possible that they are so complete in the DIRECT form, that they also provide anti-PD1L antibodies thus eliminating the need for a cocktail. Right now that latter theory is simply conjecture, but if proven accurate, every other cancer therapy company will have difficulty surviving.
7. The additional exponentially produced dendritic cells also provide an overwhelming immune response that the body could not replicate on its own. Kinda like the Powell Doctrine.
