Attachment of cell fragments of Fusobacterium nucleatum to oral epithelial cells, gingival fibroblasts and white blood cells.

The characteristic haemagglutination (HA) caused by Fusobacterium nucleatum strains was used for measuring their attachment to oral epithelial, gingival fibroblast and white blood cells. Whole cells and sonicated preparations of oral F. nucleatum strains VPI No. 4355, 10197 and ATCC No. 10953 haemagglutinated human and sheep red blood cells. Sonicated preparations of the organisms were tested for HA activity before and after absorption with human cells. Buccal epithelial, gingival fibroblast and white blood cells bound the HA-active fragments, as observed by: (1) decrease in the HA activity of the sonicated preparation after absorption, (2) increase in HA activity of the cells used for absorption, (3) presence of microbial fragments on the cells after absorption detected by fluorescent antibody. The HA-active fragments were released from the cells by EDTA; furthermore, galactose but not glucose inhibited the attachment of F. nucleatum to human cells. The role of cell binding in colonization by the organisms and in immune-stimulated damage to host cells is important.