Current understanding of immune priming phenomena in insects

It may seem that the most important issues related to insect immunity have already been described. However, novel phenomena observed in recent years shed new light on the understanding of the immune response in insects. The adaptive abilities of insects helped them to populate all ecological land niches. One important adaptive ability of insects that facilitates their success is the plasticity of their immune system. Although they only have innate immune mechanisms, insects can increase their resistance after the first encounter with the pathogen. In recent years, this phenomenon, named immune priming, has become a hot topic in immunobiology. Priming can occur within or across generations. In the first case, the resistance of a given individual can increase after surviving a previous infection. Transstadial immune priming occurs when infection takes place at one of the initial developmental stages and increased resistance is observed at the pupal or imago stages. Priming across generations (transgenerational immune priming, TGIP) relies on the increased resistance of the offspring when one or both parents are infected during their lifetime. Despite the attention that immune priming has received, basic questions remain to be answered, such as regulation of immune priming at the molecular level. Research indicates that pathogen recognition receptors (PRRs) can be involved in the priming phenomenon. Recent studies have highlighted the special role of microRNAs and epigenetics, which can influence expression of genes that can be transmitted through generations although they are not encoded in the nucleotide sequence. Considerable amounts of research are required to fully understand the mechanisms that regulate priming phenomena. The aim of our work is to analyse thoroughly the most important information on immune priming in insects and help raise pertinent questions such that a greater understanding of this phenomenon can be obtained in the future.

Automated summary

Insect immunity is a complex and interesting field, with recent discoveries shedding light on the adaptive abilities of insects and their immune system plasticity. Immune priming, a phenomenon where insects increase their resistance after encountering pathogens, can occur within individuals or across generations, highlighting the role of parental infection in offspring resistance. Further research is needed to understand the molecular mechanisms and regulatory factors underlying immune priming in insects.