Mycoplasma hyopneumoniae adheres to the cilia and apical plasma membrane of cells that line the trachea, bronchi, and bron ch ioles. Colonization result s in ciliostasis and peribronchial and peribronchi olar nod ular aggregates of lymphocytes and plasma cells.">Altho ugh adhesion-receptor interaction s between the organism and respiratory epithelial cells have been examined, little attention has been given to the morphologic and phenotypic changes that may occur in cells lining bron chioles during infection. In this study, we describe morphologic cha nges and differenc es in lectin staining patt ern s in the bron chi oles from lungs of six pigs necropsied at sequential stages of infect ion with M. hyopneumoniae