Ascaris Antigens Suppress Experimental Allergic Inflammation

Abstract

RATIONALE: Evaluate the potential of pseudocoelomic fluid (PCF) from Ascaris in modulating immune responses to ragweed allergen using a mouse model.METHODS: In order to characterize the allergic immunosuppression by A. suum antigens, we have adopted a two-pronged in vivo and in vitro approach. We assessed the in vivo effects of PCF and ABA-1, the predominant protein in PCF, in a ragweed sensitized mouse model of asthma using histological examination. IL-4, IL-5 and IL-13 cytokine levels assessed using multiplex bead immunoassay in BAL fluid. In vitro studies using bone marrow-derived dendritic cells (bmDC) were employed to evaluate the suppression of co-stimulatory molecules such as CD40 and CD86 in response to PCF by flow cytometry. Production of Th1/Th2 cytokines by bmDCs in response to ABA-1 and PCF exposure was assessed using multiplex bead immunoassay.RESULTS: Protection could be seen by significantly decreased cell numbers in BALF, decreased eosinophilic infiltration and reduced lung pathology in RW/PCF and RW/ABA-1 group compared to RW alone group. IL-5 and IL-13 levels in BALF were significantly reduced in PCF group compared to RW alone. PCF was able to down-regulate the expression of costimulatory molecules and production of IL-12 by dendritic cells in response to LPS in vitro demonstrating its immunosuppressive properties. Inactivation of proteins lead to increased bmDC activation as evidenced by upregulation of CD40 and CD86 as well as increased IL-12 production. These findings suggested that the protein component of PCF might play a role in protection.CONCLUSIONS:A. suum antigens appear to modulate allergic inflammation and potential regulatory mechanisms are currently under investigation. RATIONALE: Evaluate the potential of pseudocoelomic fluid (PCF) from Ascaris in modulating immune responses to ragweed allergen using a mouse model. METHODS: In order to characterize the allergic immunosuppression by A. suum antigens, we have adopted a two-pronged in vivo and in vitro approach. We assessed the in vivo effects of PCF and ABA-1, the predominant protein in PCF, in a ragweed sensitized mouse model of asthma using histological examination. IL-4, IL-5 and IL-13 cytokine levels assessed using multiplex bead immunoassay in BAL fluid. In vitro studies using bone marrow-derived dendritic cells (bmDC) were employed to evaluate the suppression of co-stimulatory molecules such as CD40 and CD86 in response to PCF by flow cytometry. Production of Th1/Th2 cytokines by bmDCs in response to ABA-1 and PCF exposure was assessed using multiplex bead immunoassay. RESULTS: Protection could be seen by significantly decreased cell numbers in BALF, decreased eosinophilic infiltration and reduced lung pathology in RW/PCF and RW/ABA-1 group compared to RW alone group. IL-5 and IL-13 levels in BALF were significantly reduced in PCF group compared to RW alone. PCF was able to down-regulate the expression of costimulatory molecules and production of IL-12 by dendritic cells in response to LPS in vitro demonstrating its immunosuppressive properties. Inactivation of proteins lead to increased bmDC activation as evidenced by upregulation of CD40 and CD86 as well as increased IL-12 production. These findings suggested that the protein component of PCF might play a role in protection. CONCLUSIONS:A. suum antigens appear to modulate allergic inflammation and potential regulatory mechanisms are currently under investigation.