Induction of monocyte chemoattractant protein-1 by Mycoplasma hominis in respiratory epithelial cells

Background: Very small preterm infants who have genital mycoplasmas isolate d from the trachea are at increased risk to develop bronchopulmonary dyspla sia (BPD), The early stages of BPD are characterized by inflammation, Recru itment and activation of mononuclear cells in response to mycoplasmas may b e important in the early stage of the disease, Lung epithelial cell product ion of monocyte chemoattractant protein-1 (MCP-1), a protein that attracts and activates mononuclear cells, could be critical in the regulation of mon onuclear cell migration to the lung, Methods: We examined the potential of Mycoplasma hominis (Mh) to induce MCP -1 gene expression and protein production in A549 cells, a pulmonary epithe lial cell line with characteristics of type II cells, Results: Live or heat-inactivated Mh induces MCP-1 mRNA and protein in a do se- and time-dependent manner, Stimulation of MCP-1 by Mh was not inhibited by 50 mug/mL of polymyxin B, interleukin (IL)-1ra, or neutralizing antibod ies to IL-1 alpha, IL-1 beta, or tumor necrosis factor alpha (TNF-alpha). I L-1 alpha, IL-1 beta, and TNF-alpha were not detected in conditioned media of Mh-stimulated A549 cells, Conclusions: These data suggest that Mh may participate in the inflammatory component of BPD by directly inducing epithelial cell production of cytoki nes that recruit and activate mononuclear cells.