GLYCOLIPID RECEPTORS FOR ATTACHMENT OF MYCOPLASMA-HYOPNEUMONIAE TO PORCINE RESPIRATORY CILIATED CELLS

Glycolipid receptors for Mycoplasma hyopneumoniae attachment were anal yzed by using a thin-layer chromatography (TLC) overlay assay, M. hyop neumoniae bound specifically to sulfatide, globoside, and monosialogan glioside GM3. No binding to sphingomyelin, cerebroside, lactosyl ceram ide, ceramide trihexoside, monosialogangliosides GM1 and GM2, disialog angliosides (GD1a, GD1b, and GD3), trisialoganglioside (GT1b), cholest erol, cholesterol sulfate, palmitic acid, tripalmitin, or cholesteryl palmitate was detected. Total lipids extracted from cilia of the swine respiratory epithelium, the natural targets of M. hyopneumoniae infec tion, were also separated on TLC plates and overlaid with mycoplasmas. M. hyopneumoniae bound specifically to three ciliary glycolipids iden tified as La, Lb, and Lc, Binding to Lc was stronger than to La and Lb . All three lipids were believed to be sulfated glycolipids, as determ ined by laminin binding and staining with azure A. Lc was identified a s a putative sulfatide because it had a mobility similar to that of au thentic sulfatide and comigrated with sulfatide on TLC plates. Laminin bound to La, Lb, and Lc and produced dose-dependent inhibition of adh erence of the mycoplasma to the three ciliary receptors. Binding of th e mycoplasma to sulfatide, La, Lb, and Lc was partially inhibited by d extran sulfate, heparin, fucoidan, mucin, and chondroitin sulfate B. T hese substances blocked the adherence of M. hyopneumoniae to cilia and ciliated tells as shown in a previous study (Q. Zhang, T. F. Young, a nd R. F, Ross, Infect. Immun, 62:1616-1622, 19944). These results indi cate that La, Lb, and Lc are the major native receptors for M. hyopneu moniae adherence to ciliated cells.