Abstract
The adherence of Fusobacterium necrophorum to the surface of bovine ruminal epithelial cells was paralleled by the organism's haemagglutinating ability. Treatment of the bacterial cells with haemagglutinin antiserum caused a reduction in the degree of attachment. The purified haemagglutinin became bound to the membranes of ruminal epithelial cells but lost its adherence when pre-incubated with haemagglutinin antiserum. These findings suggest that the adherence of F. necrophorum to the membrane of the ruminal cells is mediated by haemagglutinin.