I will agree therapeutically that this is true. I called it a catalyst because it makes many other products effective that otherwise wouldn't be, in that way I think of it as being the key to other things working, in that way it performs like a catalyst.
If not catalyst, I think do we then call it as a Limiting Reagent or Limiting Reactant dstock? which determines how much product is formed?? may be something even better because dc cells are indispensable here and once it becomes a ful tumor lysate based vaccine, it keeps the memory as a perpetual component in the body. Very interesting; don't know how to call it. Some biochemical engineers might know.