When the immune system encounters a new antigen, it needs to make a decision about whether to attack, or to ignore. Making the correct decision is important for fighting infections, killing cancer cells, and avoiding autoimmune diseases. The decision is made using time-dependent chemical signals and computations that occur at different places (tumor, lymph node, blood).<p>So if we think of the immune system as a computer that uses chemical signals, rather than electrical signals, how do we communicate with the immune system, to help it make the right decisions? My lab has designed a catheter that allows us to deliver time-dependent chemical signals into tumors and lymph nodes. The catheter contains a 3D printed retention mechanism to prevent migration, and it is implanted using image-guided, minimally invasive techniques. Different drugs can then be delivered into specific locations at specific times, using programmable pumps, to convince the immune system to attack cancer antigens.