Immune complex-dependent remodeling of the airway vasculature in response to a chronic bacterial infection

Chronic inflammation in the airways is associated with drama tic architectural changes in the walls of the airways and in thevasculature they contain. In this study, we show that the adaptive immune system is essential for airway remodeling that occurs in mice that are chronically infected with the respiratory pathogen Mycoplasnia pulmonis. Angiogenesis, lymphangiogenesis, and epithelial remodeling were greatly reduced in mice that lacked B cells. Substantiating a role for Ab and airway immune complexes, we found that the transfer of immune serum to B cell-deficient mice could reconstitute pathogen-induced angiogenesis. Inflammatory cells recruited to the infected airways were activated by the humoral response, and this activation correlated with the induction of genes for remodeling factors such as vascular endothelial growth factor-D. The results reveal a novel pathway whereby T cell-dependent Immoral immunity to a persistent airway infection can induce inflammation-dependent angiogenesis, dlymphangiogenesis, and chronic airway pathology.