Development and Evaluation of a Direct Sandwich Enzyme-Linked Immunosorbent Assay for the Quantification of Guinea-Pig Immunoglobulin E

Effect of local nasal immunotherapy on nasal blockage in pollen-induced allergic rhinitis of Guinea pigs

BACKGROUND

As a non-injection route for immunotherapy, local nasal immunotherapy has been examined in allergic rhinitis patients. However, it is unclear how the immunotherapy affects sneezing, biphasic nasal blockage and nasal hyperresponsiveness. Thus, we evaluated the therapeutic effects of nasal immunotherapy on the symptoms of guinea pig allergic rhinitis. Additionally, we also evaluated whether the immunotherapy relieved pollen-induced allergic conjunctivitis.

METHODS

Sensitized animals were repeatedly challenged by pollen inhalation once every week. After the 7th challenge, the pollen extract was intranasally administered 6 times a week until the 30th challenge. Sneezing frequency was counted after each of the challenges. As an indicator of nasal blockage, changes in specific airway resistance were measured. Nasal hyperresponsiveness was assessed by measuring leukotriene D(4)-induced nasal blockage. Additionally, during the immunotherapy, we applied pollen onto the ocular surface to induce the allergic conjunctivitis symptoms.

RESULTS

At the 11th-30th challenges, the nasal immunotherapy showed inhibition or a tendency to inhibit the biphasic nasal blockage although the inhibitions were variable at respective challenges. The development of nasal hyperresponsiveness was markedly suppressed by the immunotherapy. Nevertheless, neither sneezing nor antigen-specific IgE antibody production was substantially influenced by the immunotherapy. On the other hand, the nasal immunotherapy did not affect the induction of allergic conjunctivitis symptoms.

CONCLUSIONS

Local nasal immunotherapy may be clinically useful for allergic nasal blockage associated with nasal hyperresponsiveness. The mechanisms responsible for this effectiveness might not be related to IgE production. Additionally, the effectiveness for nasal tissue was dissociated from that seen for the ocular tissue.

Effects of multiple dexamethasone treatments on aggravation of allergic conjunctivitis associated with mast cell hyperplasia

In a Japanese cedar pollen-induced allergic conjunctivitis model in guinea pigs, symptoms were aggravated by repeated pollen challenges. In addition, the number of mast cells in the conjunctiva was increased by multiple challenges. The amount of a mast cell mediator, histamine in ophthalmic lavage fluid was also increased by multiple challenges. In the present study, we evaluated the effects of multiple dexamethasone treatments to assess the relationship between the aggravation of symptoms and mast cell hyperplasia. Sensitized guinea pigs were challenged by dropping a pollen suspension onto their eye surface once a week until the 15th challenge. Dexamethasone (10 mg/kg, p.o.) was administered once 3 h before the 15th challenge or 3 h before every 1st--15th challenge. Mast cells in the conjunctival tissue were detected by toluidine blue staining. Histamine was fluorometrically assayed by high-performance liquid chromatography. Serum Cry j 1-specific IgE titer was measured by an enzyme-linked immunosorbent assay. The results indicated that a single treatment with dexamethasone did not affect the 15th challenge-induced symptoms; however, multiple treatments with the corticosteroid suppressed not only conjunctivitis symptoms after every challenge but also the mast cell hyperplasia and the increase in histamine in the lavage fluid. Conversely, the increase in the IgE titer in the serum was not affected by multiple treatments with dexamethasone. In conclusion, increased numbers of mast cells in the conjunctival tissue may be associated with the aggravation of allergic conjunctivitis symptoms.

Staphylococcal enterotoxin B increases TIM4 expression in human dendritic cells that drives naïve CD4 T cells to differentiate into Th2 cells

Aberrant T helper (Th)2 polarization plays a critical role in the pathogenesis of allergic disorders; the etiology remains unclear. Dendritic cells (DCs) express T cell immunoglobulin mucin domain (TIM)4 that ligates TIM1 on CD4 T cells to drive them to become Th2 cells, but the pathogenic source of TIM4 is unknown. Here we report that a significant increase in TIM4 expression in human DCs was observed in response to Staphylococcal enterotoxin B (SEB) stimulation via Toll-like receptor (TLR)2 and nucleotide-binding oligomerization domain (NOD)1 pathway. Coculture SEB-conditioned DCs with naïve CD4 T cells induced Th2 responses that could be abolished using TLR2 or NOD1 or TIM4 or TIM1 with counterpart antibodies or RNA interference. The results demonstrate that Staphylococcus aureus derived SEB promotes the TIM4 production in human DCs. The interaction between TIM4 and TIM1 drives naïve CD4 T cells to develop to Th2 cells.