The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform
Timothy D G Lee - One of the best experts on this subject based on the ideXlab platform.
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extract of nippostrongylus brasiliensis stimulates polyclonal type 2 immunoglobulin response by inducing de novo class switch
Infection and Immunity, 2000Co-Authors: Humphrey N Ehigiator, Andrew W Stadnyk, Timothy D G LeeAbstract:Nippostrongylus brasiliensis infection in mice has been widely used to address the mechanisms involved in the regulation of the type-2 responses associated with nematodes. One significant aspect of the type-2 shift induced by this worm in mice is the bias of the immunoglobulin (Ig) response towards IgE and IgG1 (29, 72, 75). A compelling characteristic of this response is the fact that most of this Antibody is not directed against the parasite; only a small fraction is specific to nematode antigens (20, 21). This clearly indicates that nematode infection induces a polyclonal activation of Reaginic antibodies. Further to this, there is strong evidence that nematode infection will bias the developing immune response to unrelated antigens towards IgE and Reaginic IgG. For example, we (31) have shown dramatic effects on the developing Antibody response to third-party antigens by treatment with nematodes and nematode extracts. This observation is significant in that it suggests that the influence of nematodes on immune responses is far reaching and may have profound effects on developing immune responses to unrelated antigenic challenge. This could have significant effects on the outcome of vaccination strategies in areas where nematode infection is endemic. Currently, the prevailing evidence supports important roles for both interleukin-4 (IL-4) and IL-13 in IgE and IgG1 production, including such Antibody production following nematode infection. This has been confirmed by cytokine blocking experiments (1, 2, 10, 27, 72) and gene knockout experiments (25, 26, 40, 41, 51). Several in vitro culture studies have shown that production of both IgE and IgG1 is dependent on IL-4, as the addition of antibodies to either IL-4 or the IL-4 receptor completely inhibits IgE and IgG1 production (12–14). This cytokine dependence is likely due to the role of these cytokines in mediating class switch. For example, it has been demonstrated that the addition of IL-4 to cultures of either lipopolysaccharide (LPS)- or anti-CD40 Antibody-stimulated murine B cells induces high levels of germline ɛ and γ1 transcripts that correlate with the amount of IgE and IgG1 induction, respectively (5–7, 16, 23, 37, 57). Similar observations have been reported in a number of in vivo model systems (73, 74). The production of both IgE and Reaginic IgG has common regulatory elements (15, 38, 52, 59, 62); there is now convincing evidence in mice of a sequential switch from μ to γ1 and then to ɛ (38, 59, 74). Such a sequential switch has also been documented in other species (43). It is clear that IL-4 and IL-13 are involved in Reaginic Antibody production in response to nematodes. What remains to be addressed, however, is the relationship between the inflammatory parameters of infection, the products produced by the nematode, and the immunoglobulin response that follows. It is unclear whether the large polyclonal γ1/ɛ response seen after nematode infection is due to infection per se or to the elaboration of factors which either directly or indirectly mediate class switch by nematodes. The evidence that cytokine-like molecules can be produced by nematodes (17, 47) is suggestive of a direct role for nematode factors in the mediation of the γ1/ɛ response. This is of significant interest since it could form the foundation for nematode-based therapeutics. In this study, we examined the effects of a soluble Nippostrongylus protein extract on IgE and IgG1 responses in mice. We confirmed that soluble worm products are able to mediate the heightened polyclonal γ1/ɛ response and that infection is not required to mediate this response. Furthermore, we demonstrated that the soluble nematode extract induces the effect by causing de novo class switch of B cells.
H Folch - One of the best experts on this subject based on the ideXlab platform.
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detection of Reaginic antibodies against faenia rectivirgula from the serum of horses affected with recurrent airway obstruction by an in vitro bioassay
Veterinary Research Communications, 2010Co-Authors: G Moran, H Folch, Rafael A Burgos, O Araya, Miguel BarriaAbstract:Reaginic antibodies, mainly of the IgE and some IgG subclasses, play an important role in the induction of type I immediate hypersensitivity reactions. These antibodies bind through their Fc fragment to high affinity receptors (FceRI) present in the membrane of mast cells and basophils. Previously, several studies have investigated the role of Reaginic antibodies in the pathogenesis of RAO. However, whereas immunological aspects of RAO have been extensively studied, the precise sequence of events is still not well understood and role of IgE in this disease still remains controversial. Therefore, in this study a bioassay was developed for Reaginic Antibody determination in serum from RAO-affected horses in order to determine the etiology of disease. The technique involves measuring in vitro calcium mobilization in RBL-2H3 cells following incubation with horse serum from RAO-affected or unaffected horses and one of the RAO antigens (Faenia rectivirgula). Results demonstrated that 15% of samples from the RAO-affected horses reacted positively in this in vitro bioassay, whereas the samples from unaffected horses did not. This bioassay indicates that Reaginic antibodies could be involved in the immunological mechanism leading to RAO; and this technique may facilitate future research in other allergic diseases in horses.
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in vitro bioassay to detect Reaginic antibodies from the serum of horses affected with recurrent airway obstruction
Veterinary Research Communications, 2010Co-Authors: G Moran, Rafael A Burgos, O Araya, H FolchAbstract:In horses, Recurrent Airway Obstruction (RAO) is an allergic disease that involves IgE mediated Type I Hypersensitivity responses. The development of this type of allergy involves a series of events that begins with Reaginic antibodies, mainly IgE and some IgG subclasses. These Reaginic antibodies bind with high affinity, via the Fc portion, to FceRI receptors on the membrane of mast cells and basophils. Once bound, environmental allergens cross-link the antibodies, which results in mast cell degranulation leading to the production of histamine and other chemical mediators that act together to induce airway inflammation. RAO-affected horses present with coughing, respiratory distress, airway obstruction and poor performance. The aspect of the RAO has been extensively studied, yet the precise sequence of events is still not well understood. Therefore, this study proposes a bioassay for Reaginic Antibody detection from horse serum of RAO-affected individuals, in order to determine the etiology of disease, which mediate immediate type reactions. The technique involves measuring in vitro calcium mobilization in RBL-2H3 cells following incubation with horse serum from affected or unaffected horses and one of the RAO antigens (Aspergillus fumigatus). The results presented here demonstrate that 30% of RAO-affected horses react positively in this in vitro bioassay, whereas unaffected horses do not. This bioassay may facilitate further research on RAO and other allergic diseases in horses.
K Miller - One of the best experts on this subject based on the ideXlab platform.
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brown norway rat model of food allergy effect of plant components on the development of oral sensitization
Food and Chemical Toxicology, 1996Co-Authors: H Atkinson, I T Johnson, Jennifer M Gee, F Grigoriadou, K MillerAbstract:The Brown Norway (BN) rat was examined as a model for investigating factors that influence the development of food allergy. An antigen dose-response curve for the production of antigen-specific Reaginic Antibody (IgE) induced through the oral route was determined. Animals were dosed orally with 1.0, 2.5, 5.0, 7.5, 10.0 and 12.0 mg ovalbumin/ml (0.5 ml/100 g twice a week for 6 wk). To promote IgE production the adjuvant carrageenan was administered once a week by the ip route. The effect on oral sensitization of 1.5 mg Gypsophila sp. saponin/ml administered together with the antigen on oral sensitization was examined in animals treated with 2.5, 6.0 or 10.0 mg ovalbumin/ml. The number of animals producing antigen specific Reaginic Antibody in response to 2.5 mg ovalbumin/ml was significantly increased (P < 0.01) in the group that received saponin with 2.5 mg ovalbumin/ml. These studies indicate that the BN rat is a sensitive model for the investigation of allergic reactions to food and has the potential to determine the impact of other dietary factors on the development of oral sensitization.
G Moran - One of the best experts on this subject based on the ideXlab platform.
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detection of Reaginic antibodies against faenia rectivirgula from the serum of horses affected with recurrent airway obstruction by an in vitro bioassay
Veterinary Research Communications, 2010Co-Authors: G Moran, H Folch, Rafael A Burgos, O Araya, Miguel BarriaAbstract:Reaginic antibodies, mainly of the IgE and some IgG subclasses, play an important role in the induction of type I immediate hypersensitivity reactions. These antibodies bind through their Fc fragment to high affinity receptors (FceRI) present in the membrane of mast cells and basophils. Previously, several studies have investigated the role of Reaginic antibodies in the pathogenesis of RAO. However, whereas immunological aspects of RAO have been extensively studied, the precise sequence of events is still not well understood and role of IgE in this disease still remains controversial. Therefore, in this study a bioassay was developed for Reaginic Antibody determination in serum from RAO-affected horses in order to determine the etiology of disease. The technique involves measuring in vitro calcium mobilization in RBL-2H3 cells following incubation with horse serum from RAO-affected or unaffected horses and one of the RAO antigens (Faenia rectivirgula). Results demonstrated that 15% of samples from the RAO-affected horses reacted positively in this in vitro bioassay, whereas the samples from unaffected horses did not. This bioassay indicates that Reaginic antibodies could be involved in the immunological mechanism leading to RAO; and this technique may facilitate future research in other allergic diseases in horses.
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in vitro bioassay to detect Reaginic antibodies from the serum of horses affected with recurrent airway obstruction
Veterinary Research Communications, 2010Co-Authors: G Moran, Rafael A Burgos, O Araya, H FolchAbstract:In horses, Recurrent Airway Obstruction (RAO) is an allergic disease that involves IgE mediated Type I Hypersensitivity responses. The development of this type of allergy involves a series of events that begins with Reaginic antibodies, mainly IgE and some IgG subclasses. These Reaginic antibodies bind with high affinity, via the Fc portion, to FceRI receptors on the membrane of mast cells and basophils. Once bound, environmental allergens cross-link the antibodies, which results in mast cell degranulation leading to the production of histamine and other chemical mediators that act together to induce airway inflammation. RAO-affected horses present with coughing, respiratory distress, airway obstruction and poor performance. The aspect of the RAO has been extensively studied, yet the precise sequence of events is still not well understood. Therefore, this study proposes a bioassay for Reaginic Antibody detection from horse serum of RAO-affected individuals, in order to determine the etiology of disease, which mediate immediate type reactions. The technique involves measuring in vitro calcium mobilization in RBL-2H3 cells following incubation with horse serum from affected or unaffected horses and one of the RAO antigens (Aspergillus fumigatus). The results presented here demonstrate that 30% of RAO-affected horses react positively in this in vitro bioassay, whereas unaffected horses do not. This bioassay may facilitate further research on RAO and other allergic diseases in horses.
Humphrey N Ehigiator - One of the best experts on this subject based on the ideXlab platform.
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extract of nippostrongylus brasiliensis stimulates polyclonal type 2 immunoglobulin response by inducing de novo class switch
Infection and Immunity, 2000Co-Authors: Humphrey N Ehigiator, Andrew W Stadnyk, Timothy D G LeeAbstract:Nippostrongylus brasiliensis infection in mice has been widely used to address the mechanisms involved in the regulation of the type-2 responses associated with nematodes. One significant aspect of the type-2 shift induced by this worm in mice is the bias of the immunoglobulin (Ig) response towards IgE and IgG1 (29, 72, 75). A compelling characteristic of this response is the fact that most of this Antibody is not directed against the parasite; only a small fraction is specific to nematode antigens (20, 21). This clearly indicates that nematode infection induces a polyclonal activation of Reaginic antibodies. Further to this, there is strong evidence that nematode infection will bias the developing immune response to unrelated antigens towards IgE and Reaginic IgG. For example, we (31) have shown dramatic effects on the developing Antibody response to third-party antigens by treatment with nematodes and nematode extracts. This observation is significant in that it suggests that the influence of nematodes on immune responses is far reaching and may have profound effects on developing immune responses to unrelated antigenic challenge. This could have significant effects on the outcome of vaccination strategies in areas where nematode infection is endemic. Currently, the prevailing evidence supports important roles for both interleukin-4 (IL-4) and IL-13 in IgE and IgG1 production, including such Antibody production following nematode infection. This has been confirmed by cytokine blocking experiments (1, 2, 10, 27, 72) and gene knockout experiments (25, 26, 40, 41, 51). Several in vitro culture studies have shown that production of both IgE and IgG1 is dependent on IL-4, as the addition of antibodies to either IL-4 or the IL-4 receptor completely inhibits IgE and IgG1 production (12–14). This cytokine dependence is likely due to the role of these cytokines in mediating class switch. For example, it has been demonstrated that the addition of IL-4 to cultures of either lipopolysaccharide (LPS)- or anti-CD40 Antibody-stimulated murine B cells induces high levels of germline ɛ and γ1 transcripts that correlate with the amount of IgE and IgG1 induction, respectively (5–7, 16, 23, 37, 57). Similar observations have been reported in a number of in vivo model systems (73, 74). The production of both IgE and Reaginic IgG has common regulatory elements (15, 38, 52, 59, 62); there is now convincing evidence in mice of a sequential switch from μ to γ1 and then to ɛ (38, 59, 74). Such a sequential switch has also been documented in other species (43). It is clear that IL-4 and IL-13 are involved in Reaginic Antibody production in response to nematodes. What remains to be addressed, however, is the relationship between the inflammatory parameters of infection, the products produced by the nematode, and the immunoglobulin response that follows. It is unclear whether the large polyclonal γ1/ɛ response seen after nematode infection is due to infection per se or to the elaboration of factors which either directly or indirectly mediate class switch by nematodes. The evidence that cytokine-like molecules can be produced by nematodes (17, 47) is suggestive of a direct role for nematode factors in the mediation of the γ1/ɛ response. This is of significant interest since it could form the foundation for nematode-based therapeutics. In this study, we examined the effects of a soluble Nippostrongylus protein extract on IgE and IgG1 responses in mice. We confirmed that soluble worm products are able to mediate the heightened polyclonal γ1/ɛ response and that infection is not required to mediate this response. Furthermore, we demonstrated that the soluble nematode extract induces the effect by causing de novo class switch of B cells.
