Distinct Mycoplasma pneumoniae Interactions with Sulfated and Sialylated Receptors.

is a cell wall-less bacterial pathogen of the conducting airways, causing bronchitis and atypical or "walking" pneumonia in humans. recognizes sialylated and sulfated oligosaccharide receptors to colonize the respiratory tract, but the contribution of the latter is particularly unclear. We used chamber slides coated with sulfatide (3--sulfogalactosylceramide) to provide a baseline for binding and gliding motility. As expected, bound to surfaces coated with sulfatide in a manner that was dependent on sulfatide concentration and incubation temperature and inhibited by competing dextran sulfate. However, mycoplasmas bound to sulfatide exhibited no gliding motility, regardless of receptor density. also bound lactose 3'-sulfate ligated to an inert polymer scaffold, and binding was inhibited by competing dextran sulfate. The major adhesin protein P1 mediates adherence to terminal sialic acids linked α-2,3, but P1-specific antibodies that blocked hemadsorption (HA) and binding to the sialylated glycoprotein laminin by 95% failed to inhibit mycoplasma binding to sulfatide, suggesting that P1 does not mediate binding to sulfated galactose. Consistent with this conclusion, the HA-negative mutant II-3 failed to bind to sialylated receptors but adhered to sulfatide in a temperature-dependent manner.