Figure 1.

Neutrophils and lymphocytes infiltrate the airways in a time dependent manner in response to polyinosinic:polycytidylic acid (poly I:C). Inflammatory cell numbers increased in the bronchoalveolar lavage fluid (BALF) from 2 h through 168 h post-poly I:C instillation. Differential cell counts revealed that (a) neutrophils and (b) lymphocytes in the BALF were the predominant leukocyte populations that were elevated. (c) These changes were associated with airways hyper-responsive to cholinergic agents indicated by the reduced PC₁₀₀PIP (provocative concentration producing a 100% increase in pulmonary insufflation pressure) values. Data are expressed as mean±s.e.m. of n=10–12 mice. Significance (relative to the time-matched control at each time point) was determined using a Student's t-test and is denoted as follows: *P<0.05; **P<0.01; and ***P<0.001. MCh, methacholine.