Inhibitor to the cell-bound haemagglutinin of Vibrio cholerae.

An inhibitor to cell-bound HA was found to be produced at the non-haemagglutinating phase of the culture cycle by a classical vibrio strain which produced a cell-bound HA early and transiently during its growth. The HA-negative filtrate obtained from the late log-culture was found to inhibit the cell-bound HA activity produced by the same vibrio strain. It was also found to be produced early in shaking cultures at 37 degrees C and to mask the activity of early cell-bound HA in whole culture tests. This inhibitor is suggested to be responsible for the failure to obtain HA activity or adhesive vibrio cells grown at 37 degrees C and for the transient expression of cell-bound HA by some V. cholerae strains.