Pulmonary inflammation with eosinophil (EOs) infiltration is a prominent feature of allergic respiratory diseases such as asthma. In order to study the cellular response during the disease development, an animal model of IgE-mediated pulmonary inflammation with characteristic eosinophilia is needed. We developed a method for inducing severe pulmonary eosinophilia in the mouse and also studied the numbers of EOs in blood and bone marrow and the response to corticosteroid treatment. Animals were sensitized with alum-precipitated ovalbumin (OVA) and challenged with aerosolized OVA 12 days later when serum IgE levels were significantly elevated. Four to eight hours after challenge there were moderate increases in the number of EOs in the bone marrow and peripheral blood, but only a few EOs were observed in the lung tissue and in bronchoalveolar lavage (BAL) fluid. Twenty-four hours after challenge, there was a marked reduction of EOs in bone marrow, while the number of EOs peaked in the perivascular and peribronchial regions of the lung. Forty-eight hours after challenge, the highest number of EOs was found in the BAL fluid, making up > 80% of all cells in that compartment. The high levels of EOs in the lung tissue and BAL fluid lasted for 2-3 days and was followed by a more moderate but persistent eosinophilia for another 10 days. Nonsensitized animals showed no significant changes in the number of EOs in BAL fluid, lungs, blood or bone marrow. Histopathological evaluation also revealed epithelial damage, excessive mucus in the lumen and edema in the submucosa of the airways. The pulmonary eosinophilia and decrease in bone marrow EOs induced by OVA challenge responded well to treatment with several standard corticosteroids. The rank order of steroid potency for inhibition of pulmonary eosinophilia was betamethasone > prednisolone > hydrocortisone. Because mice are extremely useful for immunological studies, this model can be invaluable to study the effects of cytokines on pulmonary inflammation.

To investigate the role of interleukin-5 (IL-5) on airway hyperreactivity and pulmonary inflammation in nonhuman primate airways, the effect of a neutralizing monoclonal antibody to murine IL-5 (TRFK-5) was investigated in a cynomolgus monkey model of allergic asthma. Anesthetized Ascaris-sensitive monkeys underwent bronchoalveolar lavage (BAL) to assess the granulocyte content of this fluid before and 24 h after aerosolized Ascaris suum extract inhalation. Airway reactivity was assessed by the concentration of inhaled histamine required to produce a 40% reduction in dynamic lung compliance (Cdyn40). Exposure to A. suum extract produced an increase in airway reactivity (Cdyn40 = 0.065 +/- 0.024% before Ascaris; Cdyn40 = 0.014 +/- 0.004% after Ascaris) and an inflammatory reaction in the airways characterized by an increase in BAL eosinophils (0.05 +/- 0.03 x 10(3) cells/ml before Ascaris; 176 +/- 76 x 10(3) cells/ml after Ascaris) and neutrophils (3 +/- 1 x 10(3) cells/ml before Ascaris; 406 +/- 211 x 10(3) cells/ml after Ascaris). In contrast, only small nonsignificant changes in airway reactivity and granulocyte influx into the BAL occurred after aerosolized saline as a sham challenge. When the monkeys were treated 1 h before Ascaris challenge with the TRFK-5 antibody (0.3 mg/kg, intravenously), there was no increase in airway reactivity after Ascaris challenge (Cdyn40 = 0.032 +/- 0.016% before Ascaris; Cdyn40 = 0.217 +/- 0.196% after Ascaris) and there were only small increases in the number of eosinophils and neutrophils in the BAL after Ascaris challenge. The inhibition of this pulmonary eosinophilia and bronchial hyperresponsiveness by TRFK-5 was seen for up to 3 mo after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the role of IL-5 in airway hyperreactivity and pulmonary eosinophilia, we used a model of allergic asthma in guinea pigs and a neutralizing monoclonal antibody (TRFK-5) directed against murine IL-5. Sensitized guinea pigs were challenged with 1% ovalbumin (OVA) aerosol and assessed for airway eosinophilia (by bronchoalveolar lavage [BAL] and histologic evaluation of airway tissue) and bronchoconstrictor responsiveness to substance P (SP) (as RL100 and Cdyn40) 24 h later. OVA challenge of sensitized animals caused a significant increase in airway responsiveness to SP, with a 4.9-fold decrease in RL100 and a 4.7-fold decrease in Cdyn40. Accompanying this increased sensitivity to SP was a 9-fold increase in eosinophils recovered in BAL and a 4- to 5-fold increase in eosinophils in intrapulmonary bronchial tissue. Intraperitoneal treatment with 10 mg/kg of the IL-5 antibody 2 h before OVA challenge blocked BAL and lung tissue increases in eosinophils but had no effect on the development of airway sensitivity to SP. In contrast, similar treatment with 30 mg/kg of this antibody blocked OVA-induced increased sensitivity to SP as well as BAL and lung tissue eosinophilia. These data suggest a critical and possibly independent role for IL-5 in allergic airway hyperresponsiveness and the accumulation of eosinophils within the lung of the guinea pig.

Morton, "Acute respiratory health effects of air pollution on children with asthma in US inner cities" (2008). U.S. Environmental Protection Agency Papers. 12.

Interleukin-5 (IL-5) is important in the control of differentiation, migration, and activation of eosinophils. In order to study the role of IL-5 in the development of eosinophilic inflammation of the airways, we have used a monoclonal antibody to murine IL-5 (TRFK-5) in a murine model of allergic pulmonary inflammation. B6D2F1 mice were sensitized with alum-precipitated ovalbumin and were challenged with aerosolized ovalbumin on day 12 after sensitization. Samples of bronchoalveolar lavage (BAL) fluid, lung tissue, blood, and bone marrow aspirate were collected at different times after ovalbumin challenge. Twenty-four hours after challenge there were significant increases in the number of eosinophils in the BAL fluid, lung tissue, and blood while bone marrow eosinophils were decreased. Treatment of sensitized mice with TRFK-5 (0.01-1 mg/kg, i.p.) 2 h before ovalbumin challenge reduced the numbers of eosinophils in the BAL fluid and lung tissue and prevented the decrease in bone marrow eosinophils in a dose-dependent fashion. The number of eosinophils in the BAL fluid, peribronchial and alveolar regions of the lung was also reduced when TRFK-5 (2 mg/kg, i.p.) was given up to 5 d after ovalbumin challenge. Furthermore, there was no evidence of increased epithelial damage, edema, or the presence of mucus that could have resulted from eosinophil apoptosis and release of toxic proteins after neutralization of IL-5. These results demonstrate an important role for IL-5 in the development of eosinophilic inflammation of the airways and for the migration of eosinophils from the bone marrow into blood in response to antigen challenge.(ABSTRACT TRUNCATED AT 250 WORDS)