thanks for your answers!
1) sorry, my formulation (or rather the example) was not good enough. what I wanted to say is: of course, you already know the pathogen and the natural way this pathogen enters the host. What I know is that vaccine research has always the goal to find a delivery method that is easy and cheap (pills are easier to applicate to thousands of people than injections for instance). but what if you neglect this fact. what is "the best way" to stimulate the immune system and what are the mechanisms?
2) well, I ve thought of this, but unfortunately its not that easy... an example: I´ve read that there was a dead vaccine (I don´t remember the name, but it was against influenza) which was first produced with an adjuvants and then they ve seen that it also works without adjuvants - does this make sense? It seems like it is not really known in which case one need an adjuvants and in which case not.