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Prof. Dr. Susanne Hartmann, Institute of Immunology, Freie Universität Berlin

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Ascarids live in intimate contact with millions of bacteria in the host gut. The question arises whether and how intestinal helminths cooperate with, combat or exploit the bacterial environment. In this context we identified the following interactions so far:

I) Ascaris suum releases products with antimicrobial activity (1-2);

II) Gut microbes influence the anti-nematode immune response and nematodes potentially benefit from microbiota-driven immunomodulation (3);

III) Infections with A. suum reduce the diversity of the pig microbiome at the site of infection, independent of infection intensity (4); and

IV) The microbial community inhabiting the parasite gut is derived from the host intestine, but bacterial taxa differ in abundance comparing the two communities (4).

Our preliminary data on A. suum metabolites confirm the work of others, reporting short chain fatty acid (SCFA) release by intestinal nematodes. In addition, recently we demonstrated the high diagnostic value of anti-Ascaris IgA in serum of Kenyan school children (5) as well as in German slaughter pigs (6). Based on these findings, Doctoral Researcher 1 will work on the functional characterization of SCFA released by the three ascarid species in focus, namely A. lumbricoides, A. suum and Ascaridia galli, followed by the mechanistic investigation defining the interactions of worm metabolites with host cells and gut microbes. Doctoral Researcher 2 will combine bioinformatics and the characterization of IgA responses to answer whether core parasite microbiomes and similar roles for IgA exist across animal and human ascarid infections. In sum, these projects will evaluate the roles of metabolites derived from parasites, parasite- and host microbiomes and their interplay with IgA responses in ascariasis across species boundaries.

 

References:

1) Midha et al. Front Cell Infect Microbiol 2018; 2) Midha et al. Int J Mol Sci 2021; 3) Rausch et al. Front Immunol 2018; 4) Midha et al. Microbiome 2022; 5) Mugo et al. PLoS NTD 2024; 6) Musimbi et al. Front Immunol 2025.