Modulation of the Immune Response by Nematode Secreted Acetylcholinesterase Revealed by Heterologous Expression in Trypanosoma musculi.
Nematode parasites secrete molecules which regulate the mammalian immune system, but their genetic intractability is a major impediment to identifying and characterising the biological effects of these molecules. We describe here a novel system for heterologous expression of helminth secreted proteins in the natural parasite of mice, Trypanosoma musculi, which can be used to analyse putative immunomodulatory functions. Trypanosomes were engineered to express a secreted acetylcholinesterase from Nippostrongylus brasiliensis. Infection of mice with transgenic parasites expressing acetylcholinesterase resulted in truncated infection, with trypanosomes cleared early from the circulation. Analysis of cellular phenotypes indicated that exposure to acetylcholinesterase in vivo promoted classical activation of macrophages (M1), with elevated production of nitric oxide and lowered arginase activity. This most likely occurred due to the altered cytokine environment, as splenocytes from mice infected with T. musculi expressing acetylcholinesterase showed enhanced production of IFNγ and TNFα, with diminished IL-4, IL-13 and IL-5. These results suggest that one of the functions of nematode secreted acetylcholinesterase may be to alter the cytokine environment in order to inhibit development of M2 macrophages which are deleterious to parasite survival. Transgenic T. musculi represents a valuable new vehicle to screen for novel immunoregulatory proteins by extracellular delivery in vivo to the murine host.
Department of Life Sciences, Imperial College London.
Rachel
R
Vaux
Department of Life Sciences, Imperial College London.
Corinna
C
Schnoeller
Department of Life Sciences, Imperial College London.
Rita
R
Berkachy
Department of Life Sciences, Imperial College London.
Luke B
LB
Roberts
Department of Life Sciences, Imperial College London.
Jana
J
Hagen
Department of Life Sciences, Imperial College London.
Kleoniki
K
Gounaris
Department of Life Sciences, Imperial College London.
Murray E
http://orcid.org/0000-0002-6274-6014
ME
Selkirk
D000110:Acetylcholinesterase / Q000276:immunology* / Q000378:metabolism; D000818:Animals; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D051379:Mice; D030781:Organisms, Genetically Modified / Q000378:metabolism* / Q000469:parasitology*; D015800:Protozoan Proteins / Q000276:immunology* / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014345:Trypanosoma; D014352:Trypanosomiasis / Q000201:enzymology / Q000276:immunology*
D015800:Protozoan Proteins; D000110:Acetylcholinesterase