title: Interleukin 1 activity in haemolymph from strains of the snail Biomphalaria glabrata varying in susceptibility to the human blood fluke, Schistosoma mansoni: presence, differential expression, and biological function.
abstract: Cytokines control many of the steps in the complex pathways of immune and inflammatory responses in mammals. Recent reports also indicate that some invertebrates may produce cytokines such as interleukin 1 (IL-1). Certain strains of the snail, Biomphalaria glabrata (intermediate host for the human blood fluke, Schistosoma mansoni), possess a soluble plasma factor that stimulates the haemocyte-mediated killing of larval schistosomes, making them resistant to infection. In this study, we have sought to determine whether these snails possessed IL-1 in their plasma, and whether this cytokine was associated with resistance of B. glabrata to S. mansoni. Plasma from susceptible (M-line) and resistant (10-R2, 13-16-R1) strains of B. glabrata that had been unexposed or exposed to S. mansoni were tested for the presence of IL-1-like activity. Experiments employing both a bioassay and an immunoassay indicated that an IL-1-like molecule was present, in varying quantities, among the snail strains. Further, plasma IL-1 levels were significantly affected by exposure to S. mansoni, with levels dropping in M-line and 10-R2 snails, but increasing in the 13-16-R1 strain. However, both resistant strains maintained significantly higher IL-1 levels than M-line snails. Recombinant, human IL-1 (rhIL-1) was shown to prime haemocytes from both resistant snail strains for superoxide production, but had no effect on haemocytes from susceptible B. glabrata. Moreover, the addition of an IL-1 receptor antagonist protein (IRAP) eliminated this priming effect. Priming with rhIL-1 and/or IRAP had no effect on phagocytosis rates in any of the snail strains tested.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Biological Sciences, University of Montana, Missoula 59812.
authors.forename: W O
authors.initials: WO
authors.lastname: Granath
authors.forename: V A
authors.initials: VA
authors.lastname: Connors
authors.forename: R L
authors.initials: RL
authors.lastname: Tarleton
mesh_terms: D000818:Animals; D001681:Biological Assay; D001700:Biomphalaria / Q000276:immunology* / Q000469:parasitology*; D002460:Cell Line; D004198:Disease Susceptibility; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D006434:Hemocytes / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D051379:Mice; D010587:Phagocytosis; D012550:Schistosoma mansoni / Q000472:pathogenicity*; D013481:Superoxides / Q000378:metabolism
chemical_list: D007375:Interleukin-1; D013481:Superoxides