Involvement of P1 adhesin in gliding motility of Mycoplasma pneumoniae as revealed by the inhibitory effects of antibody under optimized gliding conditions

Abstract

To examine the participation of P1 adhesin in gliding of Mycoplasma pneumoniae, we examined the effects of an anti-P1 monoclonal antibody on individual gliding mycoplasmas. The antibody reduced the gliding speed and removed the gliding cells from the glass over time in a concentration-dependent manner but had only a slight effect on nongliding cells, suggesting that the conformational changes of P1 adhesin and its displacement are involved in the gliding mechanism.

FIG. 1.

Decrease in the number of bound cells after the addition of antibody. The number of bound cells relative to the initial number in a field of 9,600 μm² is shown. (A) The ratio of gliding cells remaining on the glass is shown for each time point after the addition of antibody to 300 (closed circles), 30 (open circles), 3 (closed triangles), and 0 (open triangles) μg/ml relative to the number of cells gliding at time zero. (B) The number of nongliding cells remaining on the glass is shown relative to the number of nongliding cells at time zero. The same symbols as those in panel (A) are used. More than 100 cells were analyzed to determine the total number of gliding and nongliding cells at the zero time point.

FIG. 2.

Gliding speed after the addition of antibody. The gliding speeds normalized according to the initial speed are presented for each time point after the addition of antibody to 100 (closed circles), 30 (open circles), 10 (closed triangles), 3 (open triangles), and 0 (closed squares) μg/ml.