Time course for the increase in pulmonary MNCs and MCp's after OVA sensitization and challenge of BALB/c mice. (A) The protocol used for induction of pulmonary inflammation is depicted. Mice are sensitized intraperitoneally (IP Imm) with OVA and alum on days 0 and 7, and then challenged with aerosolized OVA daily, beginning on days 13, 15, 17, or 19, with assay on day 20. These mice received 7, 5, 3, or 1 daily challenges, respectively. (B) The mean number (± SEM) of lung MNCs recovered per BALB/c mouse is graphed for the various numbers of daily challenges as indicated. Values are means ± SE from 5 separate experiments, with following determinations (n) in each group: 0 (5); 1 day (3); 3 days (5); 5 days (4), 7 days (4). (C) The mean (± SE) MCp concentration (MCp's/10⁶ MNCs) in the lungs of the same mice as in panel B. (D) The mean (± SE) total number of MCp's per lung from the same mice as in panel B. ^*Indicates statistical significance (P < .05) as determined by the 2-tailed Student t test.