Abstract
Invertebrate immunity was defined as simple and based on an aspecific recognition. Since twenty years there are some evidence that invertebrate immunity presented high levels of specificity. In the same way, a memory process named "immune priming" was also described in invertebrates. In this work, we studied under different aspects the immune priming in Biomphalaria glabrata, a fresh water snail, against its natural parasite Schistosoma mansoni. In a first approach we demonstrated that immune priming was genotype dependent. It also appeared that the successive developmental stages of the parasite are responsible of the total protection that occurred. Finally we were interested on the molecular mechanisms responsible of this immune priming and we identified some molecular candidates in the plasma of the snails. These molecules could be implicated in the specific recognition and/or in the parasite killing.