AUTHOR=Parks Sophia C. , Okakpu Ogadinma K. , Azizpor Pakeeza , Nguyen Susan , Martinez-Beltran Stephanie , Claudio Isaiah , Anesko Kyle , Bhatia Anil , Dhillon Harpal S. , Dillman Adler R. 

TITLE=Parasitic nematode secreted phospholipase A2 suppresses cellular and humoral immunity by targeting hemocytes in Drosophila melanogaster

JOURNAL=Frontiers in Immunology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1122451

DOI=10.3389/fimmu.2023.1122451

ISSN=1664-3224

ABSTRACT=<p>A key aspect of parasitic nematode infection is the nematodes’ ability to evade and/or suppress host immunity. This immunomodulatory ability is likely driven by the release of hundreds of excretory/secretory proteins (ESPs) during infection. While ESPs have been shown to display immunosuppressive effects on various hosts, our understanding of the molecular interactions between individual proteins released and host immunity requires further study. We have recently identified a secreted phospholipase A2 (sPLA<sub>2</sub>) released from the entomopathogenic nematode (EPN) <italic>Steinernema carpocapsae</italic> we have named Sc-sPLA<sub>2</sub>. We report that Sc-sPLA<sub>2</sub> increased mortality of <italic>Drosophila melanogaster</italic> infected with <italic>Streptococcus pneumoniae</italic> and promoted increased bacterial growth. Furthermore, our data showed that Sc-sPLA<sub>2</sub> was able to downregulate both Toll and Imd pathway-associated antimicrobial peptides (AMPs) including drosomycin and defensin, in addition to suppressing phagocytosis in the hemolymph. Sc-sPLA<sub>2</sub> was also found to be toxic to <italic>D. melanogaster</italic> with the severity being both dose- and time-dependent. Collectively, our data highlighted that Sc-sPLA<sub>2</sub> possessed both toxic and immunosuppressive capabilities.</p>