Abstract
The survival of helminths in the host over long periods of time is the result of a process of adaptation or dynamic co-evolution between the host and the parasite. However, infection with helminth parasites causes damage to the host tissues producing the release of danger signals that induce the recruitment of various cells, including innate immune cells such as macrophages (Mo), dendritic cells (DCs), eosinophils, basophils, and mast cells. In this scenario, these cells are able to secrete soluble factors, which orchestrate immune effector mechanisms that depend on the different niches these parasites inhabit. Here, we focus on recent advances in the knowledge of excretory-secretory products (ESP), resulting from helminth recognition by DCs and Mo. Phagocytes and other cells types such as innate lymphocyte T cells 2 (ILC2), when activated by ESP, participate in an intricate cytokine network to generate innate and adaptive Th2 responses. In this review, we also discuss the mechanisms of innate immune cell-induced parasite killing and the tissue repair necessary to assure helminth survival over long periods of time.
Highlights
Helminths, or worms, are invertebrate animals that comprise a broad spectrum of different pathogens able to affect human health
This study showed that in the absence of mast cells, mice infected with Heligmosomoides polygyrus bakeri or Trichuris muris revealed a deficiency in the production of the alarmins IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) derived from tissues
There have been important advances in the knowledge about how helminth parasites are recognized by dendritic cells (DCs) and regarding the capacity of these cells to induce a Th2-type response
Summary
Worms, are invertebrate animals that comprise a broad spectrum of different pathogens able to affect human health. A secreted peptide from F. hepatica called helminth defense molecule 1 (FhHDM-1) has been shown to have the ability to destabilize lysosomal acidification, which impairs Mo NLRP3 activation and inflammasome function, resulting in the downregulation of IL-1 β production These authors propose that in the absence of a Th1-type inflammatory milieu, the Th2-type immune response and parasite survival is favored (Figure 1) [31]. DC-SIGN triggering is a critical event that induces some DC regulatory functions, such as the ability of these cells to induce anergic/Treg cells [38] Overall, all these results highlight the importance of improved knowledge about innate immunity receptors such as C-type lectins in the recognition and decoding of helminth molecular patterns, which are relevant to the induction of immunoregulatory responses
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
