Effect of Rolipram, a Phosphodiesterase IV Inhibitor, on Allergic Footpad Swelling using Various Adjuvants in Mice

Ligustrazine Inhibits Lung Phosphodiesterase Activity in a Rat Model of Allergic Asthma

Objectives

This study sought to examine whether ligustrazine was capable of inhibiting phosphodiesterase (PDE) activity and improving lung function in a rat model of asthma.

Methods

Rats were initially sensitized using ovalbumin (OVA) and then were challenged daily with aerosolized OVA beginning 14 days later (30 min/day) to generate a rat model of asthma. Changes in airway function following methacholine (MCh) injection were evaluated by monitoring lung resistance (R_L) and dynamic lung compliance (C_dyn) values using an AniRes2005 analytic system. In addition, serum IgE was measured via ELISA, while PDE expression was evaluated via qPCR and western blotting. Key Findings. Ligustrazine significantly impaired allergen-induced lung hyperresponsivity and inflammation in this asthma model system. Ligustrazine treatment was also associated with reduced expression of PDEs including PDE4 in the lungs of these rats.

Conclusions

Ligustrazine suppresses airway inflammation and bronchial hyperresponsivity in this rat model system, and these changes are associated with decreased PDE expression at the protein and mRNA levels.

Intravenous IgA complexed with antigen reduces primary antibody response to the antigen and anaphylaxis upon antigen re-exposure by inhibiting Th1 and Th2 activation in mice

CONTEXT

Serum IgG, IgE and IgM have been shown to enhance the primary antibody responses upon exposure to the soluble antigens recognized by those antibodies. However, how IgA affects these responses remains unknown.

OBJECTIVE

We investigated the effects of intravenously administered monoclonal IgA on the immune responses in mice.

MATERIALS AND METHODS

DBA/1J mice were immunized with ovalbumin in the presence or absence of anti-ovalbumin monoclonal IgA. The Th1 and Th2 immune responses to ovalbumin and the anaphylaxis induced by re-exposure to ovalbumin were measured.

RESULTS

IgA complexed with antigen attenuated the primary antibody responses to the antigen in mice, in contrast to IgG2b and IgE. The primary antibody responses, i.e. the de novo synthesis of anti-ovalbumin IgG2a, IgG1 and IgE in the serum, and the subsequent anaphylaxis induced with re-exposure to ovalbumin were reduced by the co-injection of anti-ovalbumin monoclonal IgA at ovalbumin immunization. The Th1, Th2 and Tr1 cytokines interferon-γ, interleukin-4 and interleukin-10, respectively, released from ovalbumin-restimulated cultured splenocytes collected from allergic mice were also reduced by the treatment. The induction of interferon-γ and interleukin-4 secretion by splenocytes from ovalbumin-immunized mice stimulated in vitro with ovalbumin was also significantly reduced by the antigen complexed with anti-ovalbumin IgA.

CONCLUSION

These data suggest that the direct inhibition of Th1 and Th2 activation by anti-ovalbumin monoclonal IgA participates in the inhibition of the primary antibody responses. IgA plays important immunosuppressive roles under physiological and pathological conditions and is a promising candidate drug for the treatment of immune disorders.

Tyrosine kinase inhibitor sunitinib relieves systemic and oral antigen-induced anaphylaxes in mice

BACKGROUND

  Systemic and oral antigen-induced anaphylaxes are mediated by immunoglobulin (Ig) E and mast cells, but there is no satisfactory treatment for the life-threatening allergic reaction. We investigated the potential of the multitargeted receptor tyrosine kinase inhibitor sunitinib to relieve anaphylactic reactions in food allergy and systemic anaphylaxis.

METHODS

  Efficacy of oral sunitinib on oral and parenteral antigen-induced anaphylaxes in Balb/c mice was evaluated. IgE-dependent degranulation and growth of rat basophilic leukemia RBL2H3 and bone marrow-derived mast cells (BMMCs) in response to sunitinib were investigated.

RESULTS

  Daily administration of sunitinib throughout antigen challenges prevented oral antigen-induced anaphylaxis including diarrhea, anaphylactic symptoms, and hypothermia. The mouse mast cell protease (MMCP)-1 concentration in serum and mast cell number in intestinal tissue after challenge were also decreased by the treatment. Spleen cells from sunitinib-treated mice contained smaller numbers of antigen-specific IgG-producing cells and secreted lower amounts of both Th1 and Th2 cytokines than those of the control mice, whereas the levels of antigen-specific antibodies in serum were not decreased. The reactions and MMCP-1 release in oral antigen-induced anaphylaxis and passive systemic anaphylaxis were attenuated even by a single predose of sunitinib. Degranulation and growth of RBL2H3 cells and BMMCs were greatly reduced by sunitinib.

CONCLUSION

  These results suggested that sunitinib relieves systemic and oral antigen-induced anaphylaxes by the prevention of mast cell activation and hyperplasia in intestinal tissue directly and indirectly through an immunosuppressive effect. Sunitinib and its related kinase inhibitors might be potential drugs for the treatment of food allergy and systemic anaphylaxis.