Browsing by Author "Darby, Matthew G"

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    Open Access
    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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    Disruption of maternal gut microbiota during gestation alters offspring microbiota and immunity
    (BioMed Central, 2018-07-07) Nyangahu, Donald D; Lennard, Katie S; Brown, Bryan P; Darby, Matthew G; Wendoh, Jerome M; Havyarimana, Enock; Smith, Peter; Butcher, James; Stintzi, Alain; Mulder, Nicola; Horsnell, William; Jaspan, Heather B
    Background: Early life microbiota is an important determinant of immune and metabolic development and may have lasting consequences. The maternal gut microbiota during pregnancy or breastfeeding is important for defining infant gut microbiota. We hypothesized that maternal gut microbiota during pregnancy and breastfeeding is a critical determinant of infant immunity. To test this, pregnant BALB/c dams were fed vancomycin for 5 days prior to delivery (gestation; Mg), 14 days postpartum during nursing (Mn), or during gestation and nursing (Mgn), or no vancomycin (Mc). We analyzed adaptive immunity and gut microbiota in dams and pups at various times after delivery. Results In addition to direct alterations to maternal gut microbial composition, pup gut microbiota displayed lower α-diversity and distinct community clusters according to timing of maternal vancomycin. Vancomycin was undetectable in maternal and offspring sera, therefore the observed changes in the microbiota of stomach contents (as a proxy for breastmilk) and pup gut signify an indirect mechanism through which maternal intestinal microbiota influences extra-intestinal and neonatal commensal colonization. These effects on microbiota influenced both maternal and offspring immunity. Maternal immunity was altered, as demonstrated by significantly higher levels of both total IgG and IgM in Mgn and Mn breastmilk when compared to Mc. In pups, lymphocyte numbers in the spleens of Pg and Pn were significantly increased compared to Pc. This increase in cellularity was in part attributable to elevated numbers of both CD4+ T cells and B cells, most notable Follicular B cells. Conclusion Our results indicate that perturbations to maternal gut microbiota dictate neonatal adaptive immunity.
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    The Exposome Approach in Allergies and Lung Diseases: Is It Time to Define a Preconception Exposome?
    (2021-12-01) López-Cervantes, Juan Pablo; Lønnebotn, Marianne; Jogi, Nils Oskar; Calciano, Lucia; Kuiper, Ingrid Nordeide; Darby, Matthew G; Dharmage, Shyamali C; Gómez-Real, Francisco; Hammer, Barbara; Bertelsen, Randi Jacobsen; Johannessen, Ane; Würtz, Anne Mette Lund; Mørkve Knudsen, Toril; Koplin, Jennifer; Pape, Kathrine; Skulstad, Svein Magne; Timm, Signe; Tjalvin, Gro; Krauss-Etschmann, Susanne; Accordini, Simone; Schlünssen, Vivi; Kirkeleit, Jorunn; Svanes, Cecilie
    Emerging research suggests environmental exposures before conception may adversely affect allergies and lung diseases in future generations. Most studies are limited as they have focused on single exposures, not considering that these diseases have a multifactorial origin in which environmental and lifestyle factors are likely to interact. Traditional exposure assessment methods fail to capture the interactions among environmental exposures and their impact on fundamental biological processes, as well as individual and temporal factors. A valid estimation of exposure preconception is difficult since the human reproductive cycle spans decades and the access to germ cells is limited. The exposome is defined as the cumulative measure of external exposures on an organism (external exposome), and the associated biological responses (endogenous exposome) throughout the lifespan, from conception and onwards. An exposome approach implies a targeted or agnostic analysis of the concurrent and temporal multiple exposures, and may, together with recent technological advances, improve the assessment of the environmental contributors to health and disease. This review describes the current knowledge on preconception environmental exposures as related to respiratory health outcomes in offspring. We discuss the usefulness and feasibility of using an exposome approach in this research, advocating for the preconception exposure window to become included in the exposome concept.
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    IL-4Rα-associated antigen processing by B cells promotes immunity in Nippostrongylus brasiliensis infection
    (Public Library of Science, 2013) Horsnell, William G C; Darby, Matthew G; Hoving, Jennifer C; Nieuwenhuizen, Natalie; McSorley, Henry J; Ndlovu, Hlumani; Bobat, Saeeda; Kimberg, Matti; Kirstein, Frank; Cutler, Anthony J
    In this study, B cell function in protective TH2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rα−/− mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4+ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88−/− B cells. These data suggest TLR dependent antigen processing by IL-4Rα-responsive B cells producing IL-13 contribute significantly to CD4+ T cell-mediated protective immunity against N. brasiliensis infection.
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    Preconception maternal exposure to Nippostrongylus brasiliensis transfers protection against Nb to her offspring
    (2016) Darby, Matthew G; Horsnell, William; Brombacher, Frank
    In early life the immature immune system has a reduced ability to control infection. This susceptibility is offset by transfer of protective immune components from the mother. Helminth infections are widespread and can have a long lasting influence on host immunity. Children of mothers exposed to helminth infections may display T cell sensitization to endemic helminth infections and associations have been made between maternal helminth infection and altered immune responses to childhood diseases and vaccinations. This shows that helminth-modified maternal immunity may imprint on early offspring immune development in-utero or through breast milk in the form of transfer of, for example, antibodies, cytokines and lymphocytes. Our study shows that, in mice, maternal infection with the helminth Nippostrongylus brasiliensis is not only associated with a passive transfer of antigen specific antibody(IgG1) but also inherently alters offspring immunity, increasing offspring cytokine production, alveolar macrophages, lung neutrophils and B cell population development and proliferation. Pups born to N. brasiliensis exposed mothers also had increased populations of lung and spleen CD4+ cells and higher subpopulations of central memory and effector CD4+ cells compared to pups born to naive mothers.
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    Protective immunity against Nippostrongylus brasiliensis requires antigen presentation by IL-4Rα responsive B cells
    (2012) Darby, Matthew G; Brombacher, Frank; Horsnell, William
    Nippostrongylus brasiliensis is a parasitic nematode infection that affects rodents. B-cells have been shown to play an important role in immunity to many different infections by antibody production and T-cell activation. But B-cell function in the protective TH2 response against N. brasiliensis infection is an area of immunity that is currently not well defined. Recently, it has been shown that B-cells are essential to the resolution of a Heligomosomoides polygyrus infection, another parasitic helminth. Our aim in this study was to investigate any role that B-cells may play in response to a secondary N. brasiliensis infection by analysing the differences in immunity of wild-type and B-cell-specific IL-4Rα knockout mice after a N. brasiliensis re-infection.