Oral Tolerance Reduces Eosinophil and Neutrophil Activation in a Cockroach Antigen Murine Model of Allergic Asthma.

Abstract

Our lab previously demonstrated that German cockroach allergens (CRA) induce allergic‐type airways inflammation in outbred (ICR:CD‐1) mice which closely resembles human allergic asthma. We sought to determine the efficacy of oral tolerization in alleviating asthmatic symptoms. Mice were given 8ug/day CRA by oral gavage for 4 days beginning with day ‐7, followed by intratracheal challenges with 4.75ug on day 0 and 2.4ug on days 14 and 21. Cytokines and cellular content were measured in the bronchoalveolar lavage fluid and cytokines and myeloperoxidase activity were measured in lung homogenate. Samples were collected 4 hours post final challenge and the results compared to PBS fed, CRA challenged mice. In the BAL, Eo2 and TNF were significantly reduced in tolerized mice while KC, IL‐17 and absolute Eos trended towards reduced in tolerized mice. In the lung homogenate, Eo1 and KC were significantly reduced in tolerized mice, while TNF, IL‐17 and myeloperoxidase activity trended towards reduced in tolerized mice. These results indicate that oral tolerance partially abrogates eosinophil infiltration into the lung space, as well as a decrease in parenchymal neutrophil infiltration/activation. These beneficial effects are probably mediated through a reduction in the levels of prominent cytokines associated with asthma induction and progression.Table 1: Cytokines and Cells in BAL measured in pg/mL. Cytokines and peroxidase activity in LH measured in pg/mL and absorbance versus blank resp. NM = not measured.