Elevated cytokine and chemokine levels and prolonged pulmonary airflow resistance in a murine Mycoplasma pneumoniae pneumonia model: a microbiologic,histologic, immunologic, and respiratory plethysmographic profile

Because Mycoplasma pneumoniae is hypothesized to play an important role in reactive airway disease/asthma, a comprehensive murine model of M. pneumoni ae lower respiratory infection was established. BALB/c mice were intranasal ly inoculated once with M. pneumoniae and sacrificed at 0 to 42 days postin oculation. All mice became infected and developed histologic evidence of ac ute pulmonary inflammation, which cleared by 28 days postinoculation. By co ntrast, M. pneumoniae persisted in the respiratory tract for the entire 42 days studied. Tumor necrosis factor alpha, gamma interferon, interleukin-6 (IL-6), KC (functional IL-8), MIP-la, and MCP-1/JE concentrations were sign ificantly elevated in bronchoalveolar lavage samples, whereas IL-4 and IL-1 0 concentrations were not significantly elevated. Pulmonary airflow resista nce, as measured by plethysmography, was detected 1 day postinoculation and persisted even after pulmonary inflammation had resolved at day 28. Serum anti-M. pneumoniae immunoglobulin G titers were positive in all mice by 35 days. This mouse model provides a means to investigate the immunopathogenes is of M. pneumoniae infection and its possible role in reactive airway dise ase/asthma.