Immune priming: An overview in insects

Abstract

A characteristics feature of living systems is the ability to provide protection from different kinds of infection and various toxins. Importantly in insects, innate immune response is the most fascinating phenomenon. Though vertebrates' specific adaptive immune system is lacking in invertebrates including insects, defence priming is integral to many insect species. Immune priming is defined as the improved protection by the host to the same infectious agent upon a second encounter. This protection could be species/strain-specific, may be rendering lifetime protection or can be transgenerational. These attributes hence are effective protective system against a range of pathogens. Transgenerational immune priming can be attained primarily by two ways - direct parental transfer or elevated endogenous offspring immunity. The exact mechanisms for direct parental transfer is poorly understood though ways proposed involves direct transfer of antimicrobial peptides and mediators like lysozymes in the cytoplasm of the egg, epigenetic phenomenon like genomic imprinting or transfer of microbial fragments directly by the parents. Hence immune priming in insects are important line of defence and herein in this article an attempt on the elucidation of this phenomenon in the context of insects is done.