Helminthic host defense peptides: using the parasite to defend the host.

Research of host defense peptides (HDPs) produced by helminths has been mostly neglected, although they are a segment of important cues within the tripartite communication among the parasite, host, and associated microbiota. Helminthic HDPs have low or no cyto- and genotoxicity toward host cells, in contrast to HDPs of free-living metazoans, which significantly hinders the use of the latter in preclinical and clinical studies in humans. Flatworm HDPs express a potent immunomodulatory activity, in contrast to nematode HDPs that express a potent antimicrobial activity, which might be a result of particular evolutionary adaptation, but this observation requires further investigation over a broader range of taxa. In silico prospecting of helminth genomes is a key for identifying known and novel HDP families, but it should be seconded by a functional screening approach. Parasitic helminths are destined to share niches with a variety of microbiota that inevitably influence their interaction with the host. To modulate the microbiome for their benefit and defend against pathogenic isolates, helminths have developed host defense peptides (HDPs) and proteins as integral elements of their immunity. These often exert a relatively nonspecific membranolytic activity toward bacteria, sometimes with limited or no toxicity toward host cells. With a few exceptions, such as nematode cecropin-like peptides and antibacterial factors (ABFs), helminthic HDPs are largely underexplored. This review scrutinizes current knowledge on the repertoire of such peptides in helminths and promotes their research as potential leads for an anti-infective solution to the burgeoning problem of antibiotic resistance. [ABSTRACT FROM AUTHOR]