Browsing by Author "Hoving, J Claire"

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    A cross-reactive monoclonal antibody to nematode haemoglobin enhances protective immune responses to Nippostrongylus brasiliensis
    (Public Library of Science, 2013) Nieuwenhuizen, Natalie E; Meter, Jeanne M; Horsnell, William G; Hoving, J Claire; Fick, Lizette; Sharp, Michael F; Darby, Matthew G; Parihar, Suraj P; Brombacher, Frank; Lopata, Andreas L
    Background: Nematode secreted haemoglobins have unusually high affinity for oxygen and possess nitric oxide deoxygenase, and catalase activity thought to be important in protection against host immune responses to infection. In this study, we generated a monoclonal antibody (48Eg) against haemoglobin of the nematode Anisakis pegreffii, and aimed to characterize cross-reactivity of 4E8g against haemoglobins of different nematodes and its potential to mediate protective immunity against a murine hookworm infection. Methodology/Principal Findings: Immunoprecipitation was used to isolate the 4E8g-binding antigen in Anisakis and Ascaris extracts, which were identified as haemoglobins by peptide mass fingerprinting and MS/MS. Immunological cross-reactivity was also demonstrated with haemoglobin of the rodent hookworm N. brasiliensis. Immunogenicity of nematode haemoglobin in mice and humans was tested by immunoblotting. Anisakis haemoglobin was recognized by IgG and IgE antibodies of Anisakis-infected mice, while Ascaris haemoglobin was recognized by IgG but not IgE antibodies in mouse and human sera. Sequencing of Anisakis haemoglobin revealed high similarity to haemoglobin of a related marine nematode, Psuedoterranova decipiens, which lacks the four –HKEE repeats of Ascaris haemoglobin important in octamer assembly. The localization of haemoglobin in the different parasites was examined by immunohistochemistry and associated with the excretory-secretary ducts in Anisakis, Ascaris and N. brasiliensis. Anisakis haemoglobin was strongly expressed in the L3 stage, unlike Ascaris haemoglobin, which is reportedly mainly expressed in adult worms. Passive immunization of mice with 4E8g prior to infection with N. brasiliensis enhanced protective Th2 immunity and led to a significant decrease in worm burdens. Conclusion: The monoclonal antibody 4E8g targets haemoglobin in broadly equivalent anatomical locations in parasitic nematodes and enhances host immunity to a hookworm infection.
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    Delayed goblet cell hyperplasia, acetylcholine receptor expression, and worm expulsion in SMC-specific IL-4Ralpha-deficient mice
    (Public Library of Science, 2007) Horsnell, William G C; Cutler, Antony J; Hoving, J Claire; Mearns, Helen; Myburgh, Elmarie; Arendse, Berenice; Finkelman, Fred D; Owens, Gary K; Erle, Dave; Brombacher, Frank
    Interleukin 4 receptor α (IL-4Rα) is essential for effective clearance of gastrointestinal nematode infections. Smooth muscle cells are considered to play a role in the type 2 immune response-driven expulsion of gastrointestinal nematodes. Previous studies have shown in vitro that signal transducer and activator of transcription 6 signaling in response to parasitic nematode infection significantly increases smooth muscle cell contractility. Inhibition of the IL-4Rα pathway inhibits this response. How this response manifests itself in vivo is unknown. In this study, smooth muscle cell IL-4Rα-deficient mice (SM-MHC Cre IL-4Rα −/lox ) were generated and characterized to uncover any role for IL-4/IL-13 in this non-immune cell type in response to Nippostrongylus brasiliensis infection. IL-4Rα was absent from α-actin-positive smooth muscle cells, while other cell types showed normal IL-4Rα expression, thus demonstrating efficient cell-type-specific deletion of the IL-4Rα gene. N. brasiliensis -infected SM-MHC Cre IL-4Rα −/lox mice showed delayed ability to resolve infection with significantly prolonged fecal egg recovery and delayed worm expulsion. The delayed expulsion was related to a delayed intestinal goblet cell hyperplasia, reduced T helper 2 cytokine production in the mesenteric lymph node, and reduced M3 muscarinic receptor expression during infection. Together, these results demonstrate that in vivo IL-4Rα-responsive smooth muscle cells are beneficial for N. brasiliensis expulsion by coordinating T helper 2 cytokine responses, goblet hyperplasia, and acetylcholine responsiveness, which drive smooth muscle cell contractions.
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    Deletion of IL-4Ralpha on CD4 T cells renders BALB/c mice resistant to Leishmania major infection
    (Public Library of Science, 2007) Radwanska, Magdalena; Cutler, Antony J; Hoving, J Claire; Magez, Stefan; Holscher, Christoph; Bohms, Andreas; Arendse, Berenice; Kirsch, Richard; Hunig, Thomas; Alexander, James
    Author Summary Leishmaniasis is a disease induced by a protozoan parasite and transmitted by the sandfly. Several forms of infection are identified, and the different diseases have wide-ranging symptoms from localized cutaneous sores to visceral disease affecting many internal organs. Animal models of human cutaneous leishmaniasis have been established in which disease is induced by infecting mice subcutaneously with Leishmania major. Different strains of inbred mice have been found to be susceptible or resistant to L. major infection. "Healer" C57BL/6 mice control infection with transient lesion development. The protective response to infection in this strain is dominated by type 1 cytokines inducing parasite killing by nitric oxide. Conversely, "nonhealer" BALB/c mice are unable to control infection and develop nonhealing lesions associated with a dominant type 2 immune response driven by cytokines IL-4 and IL-13. However, mice deficient in IL-4/IL-13 signaling are not protected against development of cutaneous leishmaniasis. Here we describe a BALB/c mouse where the ability to polarize to a dominant type 2 response is removed by cell-specific deletion of the receptor for IL-4/IL-13 on CD4 + T cells. These mice are resistant to L. major infection similar to C57BL/6 mice, which highlights the role of T helper 2 cells in driving susceptibility and the protective role of IL-4/IL-13 signaling in non-CD4 + T cells in BALB/c mice.
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    Investigating the role of IL-4/IL-13 and their receptors in ulcerative colitis
    (2010) Hoving, J Claire; Brombacher, Frank
    Ulcerative colitis (UC) is a heterogeneous inflammatory bowel disease (IBD) associated with chronic inflammation of the gastrointestinal tract. Characterized by genetic and immunological abnormalities, UC has overly aggressive T-cell responses to commensal bacteria eventually leading to disease pathology. UC is distinguished from Crohn's disease, another form of IBD, in that it is driven by a T helper type 2 (Th2) immune response. Oxazolone-induced colitis is a mouse model resembling UC presenting with inflammation limited to the distal colon and mixed neutrophil/lymphocyte infiltration in the superficial layer of the mucosa. The Th2 cytokines interleukin (IL)-4 and IL-13 are associated with the onset of oxazolone colitis and both signal through a common IL-4 receptor-alpha chain (IL-4R +-). Neutralizing these cytokines prevents or ameliorates disease significantly, while neutralizing IL-12 exacerbates disease symptoms. As many aspects of the mechanisms involving Th2 cytokines in colitis remain undefined, the aim of this study was to investigate the role of IL-4 and IL-13 and the receptors through which they signal in oxazolone-induced colitis. Previous studies have highlighted a role for IL-4 and IL-13 in mediating oxazolone colitis. We show that while IL-13-deficient BALB/c mice were protected from disease onset, IL-4R +- deficient BALB/c mice developed exacerbated disease symptoms.
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    Nippostrongylus-induced intestinal hypercontractility requires IL-4 receptor alpha-responsiveness by T cells in mice
    (Public Library of Science, 2012) Schmidt, Saskia; Hoving, J Claire; Horsnell, William G C; Mearns, Helen; Cutler, Antony J; Brombacher, Tiroyaone M; Brombacher, Frank
    Gut-dwelling helminthes induce potent IL-4 and IL-13 dominated type 2 T helper cell (T H 2) immune responses, with IL-13 production being essential for Nippostrongylus brasiliensis expulsion. This T H 2 response results in intestinal inflammation associated with local infiltration by T cells and macrophages. The resulting increased IL-4/IL-13 intestinal milieu drives goblet cell hyperplasia, alternative macrophage activation and smooth muscle cell hypercontraction. In this study we investigated how IL-4-promoted T cells contributed to the parasite induced effects in the intestine. This was achieved using pan T cell-specific IL-4 receptor alpha-deficient mice (iLck cre IL-4Rα −/lox ) and IL-4Rα-responsive control mice. Global IL-4Rα −/− mice showed, as expected, impaired type 2 immunity to N. brasiliensis . Infected T cell-specific IL-4Rα-deficient mice showed comparable worm expulsion, goblet cell hyperplasia and IgE responses to control mice. However, impaired IL-4-promoted T H 2 cells in T cell-specific IL-4Rα deficient mice led to strikingly reduced IL-4 production by mesenteric lymph node CD4 + T cells and reduced intestinal IL-4 and IL-13 levels, compared to control mice. This reduced IL-4/IL-13 response was associated with an impaired IL-4/IL-13-mediated smooth muscle cell hypercontractility, similar to that seen in global IL-4Rα −/− mice. These results demonstrate that IL-4-promoted T cell responses are not required for the resolution of a primary N. brasiliensis infection. However, they do contribute significantly to an important physiological manifestation of helminth infection; namely intestinal smooth muscle cell-driven hypercontractility.