title: A pathogenic parasite interferes with phagocytosis of insect immunocompetent cells.
abstract: Phagocytosis activity of hemocytes of the host Galleria mellonella (Lepidoptera) was modulated by the infection of the entomopathogenic nematode Steinernema feltiae (Rahbditida) and was found to be correlated with the opsonization of bacteria by hemolymph factors. The presence of nematodes resulted in a significative decrease in phagocytosis of bacteria by host hemocytes, both in in vivo and in in vitro assays. Host interacting proteins (HIPs), which appear to function as opsonic factors and are essential to perform immune responses, were removed by S. feltiae from host hemolymph, by means of its epicuticle binding properties. Host humoral factors sequestered by the parasite have been identified by monodimensional and 2D electrophoretic analysis. The data suggest that S. feltiae, living in association with symbiontic bacteria (Xenorhabdus nematophilus), develop an immune suppressive strategy to support its bacteria, which diminished the effectiveness of immunological surveillance by the host.
authors.affiliation: Lab of Comparative Immunology, DBSF, University of Insubria, via JH Dunant, 3, 21100 Varese, Italy. maurizio.brivio@uninsubria.it
authors.forename: Maurizio F
authors.initials: MF
authors.lastname: Brivio
authors.forename: Maristella
authors.initials: M
authors.lastname: Mastore
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Nappi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional; D006090:Gram-Negative Bacteria / Q000276:immunology* / Q000472:pathogenicity; D016905:Gram-Negative Bacterial Infections / Q000276:immunology* / Q000382:microbiology / Q000473:pathology / Q000503:physiopathology; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000469:parasitology / Q000473:pathology; D006458:Hemolymph / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology / Q000469:parasitology; D006790:Host-Parasite Interactions; D054884:Host-Pathogen Interactions; D057131:Immune Evasion; D019476:Insect Proteins / Q000302:isolation & purification / Q000378:metabolism*; D007915:Lepidoptera / Q000276:immunology* / Q000382:microbiology / Q000469:parasitology; D009348:Nematoda / Q000276:immunology* / Q000472:pathogenicity; D009349:Nematode Infections / Q000276:immunology* / Q000382:microbiology / Q000473:pathology / Q000503:physiopathology; D009895:Opsonin Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010587:Phagocytosis / Q000276:immunology*; D011485:Protein Binding
chemical_list: D019476:Insect Proteins; D009895:Opsonin Proteins