Specificity, learning and memory in the innate immune response

Immunity in invertebrates was for long analyzed in terms of the overall response; this resulted in misunderstandings concerning specificity and memory. Recent reports of maternal transmission of immunity, and the discovery of the high diversity of receptors-effectors, have required the status of innate immunity to be reconsidered. There are few examples of obvious specificity towards some pathogens, but this cannot be generalized to all invertebrate species. The existence of memory is even more controversial. Here, we suggest looking for immune memory by quantifying key molecular effectors (i) within single individuals following first and second exposures to a pathogen and (ii) in primed mother and her offspring.