The expression of peptidoglycan recognition protein-S1 gene in the scallop Chlamys farreri was enhanced after a second challenge by Listonella anguillarum.

A more rapid and powerful response against repeated exposure of same pathogen in vertebrates is usually considered as the reflection of immunological memory, but it is not well understood in invertebrates. In the present study, the temporal expression profiles of Chlamys farreri peptidoglycan recognition protein-S1 (CfPGRP-S1) gene after two challenges of Listonella anguillarum were examined to evaluate priming response in scallops. The up-regulation of CfPGRP-S1 mRNA occurred 3h earlier, and the expression level was significant higher (P<0.05), after the second challenge than that after the first challenge. The preliminary results provided new insights into invertebrate immunological memory, and they also would be helpful to develop strategies for disease control.