Respiratory tract organ cultures to assay attachment and pathogenicity of mycoplasmas.

A comparison of various in vitro models of respiratory tissue is presented. Tracheal ring explant cultures can be readily infected with M. pneumoniae. A decrease in vigor and extent of ciliary beating becomes apparent 24-48 h after 60-min exposure to 10(7) cfu of mycoplasmas. Cytotoxicity can be substantiated with assays of dehydrogenase activity, ATP content and oxygen uptake. For studies of pathogen attachment, perfusion culture of intact tracheas offers a distinct advantage over tracheal-ring explants. A greater proportion of the pathogen uptake is mediated by specific receptor sites because artificial cut surfaces are eliminated. Such matrix-embed/perfusion cultures have been used to assay the effectiveness of mycoplasma interactions with receptor site preparations. Triton X-100 effectively solubilizes glycoproteins which will bind with M. pneumoniae. Perfusion culture has also been used to study the synthesis and secretion of mucous glycoprotein by the respiratory epithelium.